DC rence on

................. .........

_ion 3165,

ass

nd Te

ems

ies for

Spa_and Earth

cienc lications t

Volume I

(NASA-CP-3165-Vol-I) NSSOC

CONFERENCE ON MASS STORAGE

ANO TECHNOLOGIES FOR SPACE

EARTH SCIFNCE APPLICATIONS t

I (NASA) 205 p

SYSTEMS

ANO

VOLUMF

HI/82

of a conference held at

Space Flight Center

Greenbelt, Maryland i

July 23-25, 1991
ai

-. _-, !__ |1

Jt

mj m

_, i___
NASA Conference Publication 3165, Vol. I

NSSDC Conference on

Mass Storage Systems

and Technologies for

Science

Space and Earth

Applications

Volume I

Edited by

Ben Kobler

Goddard Space Flight Center

Greenbelt, Maryland

P. C. Hariharan

and L. G. Blasso

STX Corporation

Lanham, Maryland

Proceedings of a conference held at

NASA Goddard Space Flight Center

Greenbelt, Maryland

July 23-25, 1991

National Aeronautics and

Space Administration

Office of Management

Scientific and Technical

Information Program

1992

Preface

The National Space Science Data Center (NSSDC) at NASA's Goddard Space Flight Center has

been charged with the archiving of data collected from NASA's scientific spaceflight missions

flown over the past 30 years. During this time NSSDC has accumulated an archive of several

terabytes of data. In the coming years NASA will be generating this volume of data every few

days or less. Thus, data storage media and systems become critically important to NASA ff it is

to successfully manage this data volume and to have a chance to transform these data into

scientific knowledge.

NSSDC will play an important role in NASA's awareness of and exploitation of emerging mass

storage systems, both at NSSDC and in the increasingly distributed NASA scientific data

environment. For this reason, NSSDC organized a conference at Goddard in the summer of

1991 to review the status of and the outlook for data storage media and systems. Leading

experts in each of several areas were invited to make presentations, and a highly informative

conference transpired. In order that the record of that conference be preserved, this set of

presentations is being published.

The Proceedings of the NSSDC Conference on Mass Storage Systems and Technologies for

Space and Earth Science applications are published in four volumes, with each of the first

three volumes containing the talks and presentations for that particular day. Discussions

following some of the talks are collected in the fourth volume along with introductory

biographical material on the speakers. Despite our best efforts, the questions and answers were

sometimes inaudible to the transcriptionist. An effort was made to contact the participants to

clarify the transcript, and we are grateful to the speakers who cooperated.

The success of an endeavor of this magnitude depends on the generous help and cooperation of

the participants. We would like to record our gratitude to the speakers, the audience, and in

particular, to the following individuals and organizations for their assistance:

The Program committee whose membership is listed in the front of each volume

The session chairs who kept the schedule on track:

Professor Bharat Bhushan of Ohio State University

Dr. Barbara Reagor of Bellcore

Dr. Robert Freese of Alphatronix

Mr. Patric Savage of Shell

Professor John C. Mallinson of Mallinson Magnetics

Dr. Kenneth Thibodeau of the National Archives and Records Administration

The members of the Panel Discussion and Professor Mark Kryder of Carnegie

Mellon University who moderated the discussion

The hard-working crew from Westover Consulting

Dr. Dennis E. Speliotis of Advanced Development Corporation for his help with

the transcript of the Panel Discussion

Dr. James L. Green and the National Space Science Data Center

Dr. J. H. King

Dr. P. C. Hariharan

Benjamin Kobler

iii

PI_ECED_NG PAGE BLANK NOT FILMED
NSSDC Mass Storage Conference Committee

Ben Kobler, NASA/GSFC (Chair)

John Berbert, NASA/GSFC

Sue Kelly, DOE/Sandia

Elizabeth Williams, SRC/Bowie

AI Dwyer, STX Corporation *

P. C. Hariharan, STX Corporation *

Sanjay Ranade, STX Corporation *

Conference Coordinator

Kim Blackwell, STX Corporation *

* Hughes STX Corporation as of October 1, 1991

iv
MASS STORAGE CONFERENCE PROCEEDINGS

CONTENTS

VOIXIME I- FIRST DAY- TUESDAY, JULY 23, 1991

I° Introduction ........................................................................................................... I- I

Dr. Milton Halem, Chief

NASA Space Data and Computing Division

° Enterprise Storage Report for the 1990s ................................................................ I-3

Fred Moore, Corporate Vice President, Strategic Planning

Storage Technology Corporation

3. Optical Disk and Tape Technology ........................................................................ 1-33

Dr. Robert Freese, President, Alphatronix

4. Magnetic Disk ........................................................................................................ 1-69

Dr. John C. Mallinson, Mallinson Magnetics, Inc.

. Magnetic Tape ......................................................................................................... 1-79

L. Harriss Robinson, Manager, Mass Storage Systems

Datatape, Inc.

6. Storage System Software Solutions For High-End User Needs ............................ 1-109

Carole Hogan, Director of Technical Development, DISCOS

7. File Servers, Networking and Supercomputers .................................................... i-145

Dr. Reagan Moore, San Diego Supercomputing Center

° Mass Storage System Experiences and Future Needs at National Center

for Atmospheric Research ..................................................................................... I- 163

Bernard T. O'Lear, Manager, Systems Programming,

Scientific Computing Division, NCAR

° The Long Hold: Storing Data At The National Archives ............

Dr. Kenneth Thibodeau, Director, Center for Electronic Records,

National Archives and Records Administration

...................... 1-183

10. Banquet Presentation ............................................................................................ 1-187

Dr. John C. Mallinson, former Director of Center for Magnetic Recording

Research, University of California, San Diego

V
STORAQE CONFERENCE PROCEEDINC_

CONTENTS {Continued}

VOLUME II - SECOND DAY- WEDNESDAY, JULY 24, 1991

1. Stewardship of Very Large Digital Data Archives ....................................................... 2-1

Patric Savage, Shell Development Company

2. High-Performance Storage Systems (Text Not Included in this Publication) ............ 2-7

Robert Coyne, IBM Federal Systems Research Division

° An Open, Parallel I/0 Computer as the Platform for High-Performance,

High-Capacity Mass Storage Systems ......................................................................... 2-9

Adrian Abineri, APTEC Computer Systems

4. EMASSTM: An Expandable Solution for NASA Space Data Storage Needs ............. 2-21

Anthony L. Peterson, P. Larry Cardwell, E-Systems, Inc.

5. Data Storage and Retrieval System ............................................................................. 2-35

Glen Nakamoto, MITRE Corporation

6. The Challenge of a Data Storage Hierarchy: Data Archiving .................................... 2-55

Michael Ruderman, Mesa Archival Systems, Inc.

7. Network Accessible Multi-Terrabyte Archive ............................................................ 2-85

Fred Rybczynskl, Metrum Information Storage

8. ICI Optical Data Storage Tape ...................................................................................... 2-98

Robert A. McLean. Joseph F. Duffy

9. ATL Products Division's Entries into the Computer Mass Storage Marketplace ...... 2- I I0

Fred Zefler, Odetics Automated Tape Library IATL)

I0. Panel D/scussion: ......................................................................................................... 2-122

Moderator: Dr. Mark Kryder

Dr, Barbara Reagor, Bellcore

Darlene M. Carlson, 3M National Media Laboratory

Kazuhiro Okamoto, Sony Magnetic Products, Inc.

Allan S. Hadad, Ampex Recording Media Corporation

John W. Corcoran, Consultant/Ampex Corporation

Dr. Dennis E. Speliotis, Advanced Development Corporation

11. Poster Session: ............................................................................................................. 2-237

Steve Atkinson, Ampex Recording Media Corporation

Barbara Matheson, STX Corporation

Kirby Collins, CONVEX Storage Systems

vi
MASS STORAGE CONFERENCE PROCEEDINGS

CONTENTS (Continued)

VOLUME Ill - THIRD DAY- THURSDAY, JULY 25, 1991

1. _'ibology of Magnetic Storage Systems .................................................................. 3-1

Dr. Bharat Bhushan, Ohio State University

2. Network Issues for Large Mass Storage Requirements ........................................... 3-73

James "Newt" Perdue, Ultra Network Technologies, Inc.

3. The Role of HIPPI Switches in Mass Storage Systems; A Five Year Prospective ...3-97

T. A. Gilbert, Network Systems Corporation

. The National Space Science Data Center: An Operational Perspective ................. 3-127

Ronald Blitstein, Hughes STX Corporation/NSSDC

Dr. James L. Green, NSSDC

5. EOSDIS / DADS Requirements ................................................................................. 3-141

John Berbert, Ben Kobler

° The Preservation of Landsat Data by the National Land Remote Sensing

Archive ..................................................................................................................... 3-153

John E. Boyd, EROS Data Center

. Status of Emerging Standards for Removable Computer Storage Media and

Related Contributions of NIST ................................................................................ 3-163

Femando L. Podio, National Institute of Standards and Technology Computer

Systems Laboratory

. Data Management in the National Oceanic and Atmospheric Administration

(NOAA) ...................................................................................................................... 3-189

William M. Callicott

9. Storage Needs in Future Supercomputer Environments ........................................ 3-211

Dr. Sam Coleman, Lawrence Livermore National Laboratory

10. Requirements for a Network Storage Service ......................................................... 3-225

Suzanne M. Kelly, Rena A. Haynes, Sandia National Laboratories

vii
MASS STORAI_E CONFERENCE PROCEEDINC_

CONTENTS (Continued)

VOLUME /I/- TRANSCRIPTIONS

Introduction of Fred Moore ............................................................................................. 3- 237

Introduction and Discussion of Dr. Robert Freese ......................................................... 3-238

Introduction and Discussion of Dr. John Mallinson ..................................................... 3-240

Introduction and Discussion of Mr. Harriss Robinson .................................................. 3-243

Introduction and Discussion of Ms. Carole Hogan ......................................................... 3-245

Introduction and Discussion of Dr. Reagan Moore. ....................................................... 3-249

Introduction and Discussion of Mr. Bernard T. O'Lear .................................................. 3-251

Introduction and Discussion of Dr. Kenneth Thibodeau ............................................... 3-254

Introduction of Mr. Patric Savage .................................................................................. 3-258

Introduction and Discussion of Mr. Adrian Abineri ..................................................... 3-259

Introduction and Discussion of Mr. Anthony L. Peterson ............................................. 3-262

Introduction and Discussion of Mr. Glen Nakamoto ..................................................... 3-265

Introduction and Discussion of Mr. Michael Ruder-man ............................................... 3-269

Introduction and Discussion of Mr. Fred Rybczynski ................................................... 3-270

Introduction and Discussion of Mr. Robert McLean ...................................................... 3-272

Introduction of Mr. Fred Zeiler. ...................................................................................... 3-275

Introduction and Discussion of Dr. Bharat Bhushan .................................................... 3-276

Introduction and Discussion of Mr, James "New_' Perdue ............................................. 3-277

Introduction and Discussion of Mr. Tom Gilbert ........................................................... 3-278

Introduction and Discussion of Mr. Ronald Blitstein .................................................... 3-279

Introduction and Discussion of Mr. John Berbert ......................................................... 3-281

Introduction and Discussion of Mr. John Boyd ............................................................. 3-282

Introduction and Discussion of Mr. Femando Podio .................................................... 3-284

,oo

viii
STORAGE CONFERENCE PROCEEDINGS

FIRST DAY- TUESDAY, JULY 23, 1991

On behalf of the Space Data and Computing Division and the NASA Goddard Space

Flight Center, I would like to say it gives us great pleasure to welcome you here and how

sincerely we feel in having this opportunity to bring together so many experts to participate in

this important and timely conference on mass storage systems and technologies.

We at Goddard have a vested interest in on-line mass data storage systems and are

anxious to leam from the experts gathered here what the field has to offer in solutions to some

of the problems NASA faces in managing its large data systems.

The emerging role of mass storage media and their proper incorporation into the

environments of NASA's computing centers and data centers is fundamental to the ultimate

success of many of our scientific missions. In particular, it is a critical element to the success

of one of the most ambitious projects NASA has ever undertaken or, for that matter, the

science community has ever undertaken, namely the Earth Observing System. planned for

launch towards the end of this decade.

But even before the launch of EOS, Just managing the existing archives and the nearterm major and moderate science discipline missions planned for the early to mid 1990's will

provide a major challenge. For example, the Great Astronomical Observatory program, which

includes the Hubble Space Telescope, the Gamma Ray Observatory, the Advanced X-Ray

Facility. in addition to a host of moderate and complementary missions such as the Rosat XRay Mission, the Astro-D mission, and others will produce several terabytes of data a year.

Similarly, the International Solar Terrestrial Program and the Earth and Planetary

Probes that are firmly scheduled for launch in the next two to three years, will consist of fleets

of spacecraft which will produce tens to even hundreds of terabytes of data from imaging

sensors and in-situ instrument measurements.

To archive and deliver this volume of data to scientists with reasonable response times

constitutes a major technological challenge today. But NASA has added an additional

requirement that the science community has requested, namely to develop and make available

a much more enabling capability for remotely accessing and analyzing these data products.

NASA will attempt to bring into being a massive distributed collection of discipline

specific data archives where all data are managed on-line and with transparent access to the

users, so that scientists and other interested groups can have near-instantaneous access, from

seconds to minutes, at worst, for browsing, querying, visualizing, and downloading data to

their local workstations.

This presents very unique technical requirements to the developers of mass data

storage systems that I believe have not yet been addressed in other applications. This is because

NASA must deal with two types of data that are somewhat unique, namely very large and

continuously evolving data sets from a finite number of instruments as well as data from very

complex modeling simulations. I like to characterize these data types as nonrecoverable and

recoverable data. respectively.

The unique aspects of these data types is not Just their massive volumes that need to be

stored on permanent, nondestructive, long-lasting media, but the need to accumulate these

data over periods of time, which might grow to be in the climatic range itself, that is, data

stored on the order of 25 to 100 years.

l-l
Already, scientists are beginning data assimilation experiments with conventional

observations dating back to the 1950s and extending up to the present day. In addition, data

must be maintained in such a way that complex computational simulation models, like

numerical weather prediction models or solar cycle oscillation models, can tlme-continuously

assimilate the entire period of multisensor observational data and multisets of computational

experiments.

Finally, I would like to conclude with a remark or a prediction that I somehow

remember reading somewhere, or perhaps paraphrasing and making it a part of my own

psyche, that goes as follows: The 1970s was the decade of the introduction of supercomputers,

which was responsible for the arrival of computational simulation for a new dimension to the

scientific paradigm comparable to experimental science. The 1980s was the decade of the

workstation and PCs, and that brought popular computing and data management and data

visualization to the scientist's desktop. But the 1990s will be the decade for on-line interactive

access to all the information knowledge that mankind has acquired. Such data systems wlll

become the libraries of the future; and I hope that, by the end of this conference, we wlll begin to

get a feel from the experts here whether this is indeed the direction of the 1990s. Thank you.

Dr. Milton Haleru, Chief

NASA Space Data and

Computing Division

I-2
StorageTek 

N93-13132

Enterprise Storage Report

for the 1990s

by Fred Moore

Corporate Vice President

Strategic Planning

Storage Technology Corporation

1-3
Enterprise Storage Report

for the 1990s

Abstract

Data processing has become an increasingly vital function, if

not the most vital function, in most businesses today. No longer

only a mainframe domain, the data processing enterprise also

includes the midrange and workstation platforms, either local

or remote. This expanded view of the enterprise has encouraged more and more businesses to take a strategic, long-range

view of information management rather than the short-term

tactical approaches of the past. This paper will highlight some

of the significant aspects of data storage in the enterprise for

the 1990s.

1-4
ENVIRONMENT - 1990s

• Storage and storage management are most

pressing issues

• Networking and connectivity requirements

increasing at all levels

• DASD subsystem reliability and availability

continue to improve

• Fault tolerant DASD architecture emerging

_=_ • Strong acceptance of automated libraries

_i • New focus and mission for magnetic tape

¢n== technologies

As the 1990s begin, effective storage management remains possibly the most pressing issue. Poor

device utilization and erratic performance are no longer accepted as normal conditions. The cost of

ineffective storage management also has received considerable attention as storage costs now

exceed the processor costs in mainframe environments.

The definition of the enterprise has moved quickly beyond the world of IBM mainframes to include

other mainframes, midrange distributed processors and networks, local and wide area. The need to

connect these processing platforms through standard network interfaces and provide access to

common storage is increasing rapidly as most users now have mixed-vendor environments (Cray,

DEC, IBM, Tandem, etc.) to manage.

The reliability of DASD subsystems continues to improve but even at 99.99 percent availability the

only acceptable goal remains 100 percent availability. This trend has encouraged several companies

to develop fault-tolerant DASD architectures. Fault-tolerant DASD subsystems provide continuous

data availability in the event of any hardware component failure.

The successful introduction of automated tape systems such as StorageTek's 4400 Automated

Cartridge System has led to widespread acceptance of automated storage. The 1980's view that

library architectures were the least reliable component of a data center is now obsolete. The data

processing industry has overcome preconceptions created by various mass storage and rail-type

architectures of the past.

The highly successful launch of automated cartridge systems has given new life to tape data

storage. Primarily used for low-activity backup, automation has allowed many new applications, not

previously considered for tape, to become pract,cal and cost-effective.

i

1-5
ENVIRONMENT- 1990s (Cont.)

• Automated operations becoming a strategic

goal for most large installations

• Accelerated new application growth in PC/

workstation segment

• Outsourcing slowing

• Disk growth rates have moderated to

25-30% annually

• Image processing market slowly emerging

IBM SYSPLEX re-focuses mainframe role

Automated operations is quickly becoming a strategic goal of most large-scale data centers.

For the first time, there is now more storage outside the "glasshouse" mainframe environment than

in it. This accelerated growth rate for storage away from the mainframe area will lead to systemmanaged storage structures, automated tape systems, multi-media libraries and fault-tolerant DASD

for the midrange and desktop computing environments.

Outsourcing, a trend that gained considerable visibility in the late 1980s, has lost some of its appeal

Sourcing some or all computer operations, services and development to a source outside the enterprise is intended to save money. Though initial short-term financial gains are possible, many users

now are viewing outsourcing as losing control of the most critical component of a business -- the

information processing function.

Mainframe DASD growth rates have moderated. In the early 1980s, DASD growth rates pushed a

60 percent annual increase in installed gigabytes As the 1990S unfold, we note that most of the

batch-to-online conversions are over. Secondly, data bases are now common, predominant in most

organizations, eliminating redundant data. The third reason is that more users are beginning to make

more effective use of storage management tools. Finally, many of the new applications that remain to

be automated are emerging slowly such as image processing. Even at 25 percent compounded annua_

growth, the installed base of DASD capacity will double every three years.

It is believed that at the mainframe, midrange and workstation levels, image processing will be the

dominant single driving factor for storage demand in the 1990s. This movement, however, has not

evolved as quickly as projected due primarily to the lack of an effective enterprisewide image management architecture.

The role of the mainframe in the 1990s was clearly esfablished by IBM's September 5, 1990,

announcement of SYSPLEX. This announcement refocused the role of the mainframe in the enterprise as the central server and overseer of the networked enterprise. Mainframe architecture will

continually drive many of the standards used for the enhre enterprise.

i

1-6
DEMAND TRENDS

Mainframes

Midrange

Workstation/

_! Desktop

Processor Demand (MIPS)

1960-

1969

15%

1970-

1979

1980-

1989

20% 40%

35% 50%

150%

1990-

1999

25%

40%

60%

Storage

Demand

(GB)

1990-

1999

25-30%

40%

55-65%

Let's take a look at some of the growth rates that we have seen in the last three decades and will see

in the future. This chart projects CPU or processor demand. Notice that processor demand for mainframes in the 1990s is expected to be around 25 percent, measured in MIPS.

We observe 25 percent growth in the mainframe, 40 percent in the midrange, and the workstation

growing overall at about 60 percent annually during the 1990s. Today MIPS demand corresponds

almost one-to-one with storage growth. Storage management and the ability to access all data

objects from all computing platforms will become both a requirement and a major architectural

challenge of the 1990s. The vendor that can resolve this problem best will control the enterprise.

1-"/
Jg Glasshouse

L- _

.o

ENTERPRISE DATA STORAGE ENVIRONMENT

ULTRANET

""J or

Library i C_y HYPERCHANNEL Super

Control t ,

Server I

_,i Server

i t

t _

i

I

r

i

Computer

DEC:

I Network _,

Hierarchical File Server _

L

Online/_,

Nearline____ 5"10%

Deep Archive / \-- 90-95%

d

! LANS _

Data;

! Base ;-_-'1

! Mach._, '---J

Network Attach

"--'_"_1 J File Sorver (EPOCH] , J

-- FioeS*rverISOt.S,rve, _

Oi,,tribute, 

We have had the traditional glasshouse or mainframe view of data processing for a long time. That

glasshouse today, dominated by MVS and VM environments, is beginning to share the spotlight with

the rapidly emerging midrange and workstation/desktop processing environments. The enterprise

now requires management of heterogeneous and complex environments. These three platforms are

clearly and distinctly emerging as major areas of processing and storage for the 1990s.

Data processing now becomes distributed at nodes in the enterprise and the objective is to allow

transparent access while maintaining the security, integrity and performance of the environment. The

role of large systems in the 1990s will become one of management and control for the information

enterprise.

We will see the migration of MIPS and storage, and the management issues that go with them,

move from mainframe to midrange and desktop. We are not going to be able to limit our views of

storage management to MVS and glasshouse and IBM-only for much longer. Storage management

solutions must cross those architectural and communication boundaries.

Nearline is a registered trademark of Storage Technology CorD.

1-8
VIRTUAL STORAGE HIERARCHY

Average

Cost/MB Performance Capacity

$4,000 80 ns 4 GB

$1,560 75 gs 16 GB

• Contains operating systems,

programs and pages

.X

9

U)

<$900 1.5 ms nX GB

Central

Expanded

Storage

Auxiliary

Storage

/i on-shared data, required

for HSP1

Can contain HSP2, data

spaces and pages

e Pagin devices, SSD and

DASD

/ • Contains HSP2 and data

/ spaces in page datasets

The virtual storage hierarchy of the 1990s will be exploited by ESA/390 architectures and consist of

three levels of storage. Central memory, at about $4,000 per megabyte, has an architectural limit of

4 gigabytes and an announced 1 gigabyte limit. Expanded storage has a 75-microsecond access

time. The limitation in present ESA/390 architecture is 16 gigabytes of addressable expanded storage,

though the announced limit is 8 gigabytes.

Solid-state products are now considerably less than $900 per megabyte and the cost per megabyte is declining quickly. In 1979 when the first SSD was introduced by Storage Technology Corp., the

original price was $8,800 per megabyte. We have seen over a 90-percent reduction in pricing on solidstate technology in the 1980 decade. The virtual storage hierarchy contains three levels including

auxiliary or paging storage. Careful use of all three technology levels offers the most cost-effective

solution to managing the virtual storage hierarchy. It is normally not cost effective for most users to

place all performance-critical data in expanded and central storage.

The ES/9000 processor series now permits migrated pages to move directly from expanded

storage to the channel subsystem (auxiliary storage paging) improving the synergy and performance

between both levels of the virtual storage hierarchy.

i| u

1-9
LARGE SYSTEMS ARCHITECTURE

1993 AND BEYOND

3090 ES/9000

Memory _ 4

CPU #1 " Applicationl CPU #3 !

, ' Real ._ i

J

_, _ Expanded -_1 !

t CPU #2 i I ! Adapters I CPU #N I

. f i

!Storage Management

L Engine

I Subsystem Control

l

4.5 - 18.0 MBtsec .all "_ b i High Speed Fiber

,_ 3990-3 I 3990-X I 3990-Y t

,_ _ 3380 3390 3390 X390 CKD Arrays

t,_ _ (lx-2x) (2x-4x) 10 MB

IBM's recent SYSPLEX announcement clearly refocused the role of the mainframe in the 1990s. Let's

examine a likely scenario for the 1993 time frame and beyond. This has often been referred to as the

post-Summit or Future Systems (FS) architecture. It is expected that up to a limit of 16 (CPU #N) ESAbased processors evolving within a SYSPLEX could be connected in the manner shown.

The continued roll-out of this architecture will include a shared expanded storage capability and

application-specific adapters implemented via software, licensed internal code and hardware in varying amounts. Hardware assists for DFSORT announced in the September 5, 1990, IBM announcement

are using this concept.

A storage management engine or I/O processor will be a new concept used to off4oad from the

host processor many of the I/O functions such as parts of lOS (1/O Supervisor), VSAM and DF (Data

Facility) functions. The storage management engine will attach peripheral devices as we know them

today (SSD, DASD, tape, printers and terminals) via the channel subsystem. Attachment of ESCON

(Enterprise System Connectivity) serial fiber channels will be preferred though parallel bus and tag

channels will need to attach via ESCON converters. The point-to-point limit of ESCON channel

transfer rates is 18 MB/se¢.

ESCON is a trademark of IBM Corporation

1-10
DIRECTION OF

RAM BASED

AUXILIARY STORAGE

ARCHITECTURES

0

i__

(3

Q

l_

0

X

::3

<

01

o'1 ,,_ ,_,,_.,.,

,- _ .,_ _ /

r_ata in Virtual

_Auxiliary Storage Paging

Applications

1980 1982 1984 1986 1988 1990

LLA

DB2

VIO

By examining RAM-based solid-state products, you will notice their use from 1979 through 1984 was

exclusively for paging. When expanded storage appeared in 1985, solid-state devices became viewed

as a high-performance disk, and non-peging data such as load libraries, catalogs and indexes were

placed on solid-state devices. The 1990s will see the MVSIESA and VM/ESA hiperspace and data

space applications drive up data in virtual requirements and force users to seriously consider using

SSD as a cost-effective complement to real and expanded storage. ESA/390 drivers of virtual storage

consumption, called methods of I/O avoidance by some, will include linear VSAM, Virtual Lookaside

Facility (VLF), hiperspace catalog, hiperspace buffers and DB2. MVS/XA systems previously using

400 to 500 megabytes of auxiliary storage will soon identify requirements exceeding 1 gigabyte or

more after migrating to ESA.

1-11
DRAM MEMORY DENSITY PROJECTIONS

Technology DRAM Development Introduction Peak

(in microns) Technology Start Date Output

1.8 256 Kbit 1977 1982-83 1988

1.2 1 Mbit 1980 1985-86 1991

0.8 4 Mbit 1983 1988-89 1994

0.6 16 Mbit 1986 1991-92 1997

0.36 64 Mbit 1989 1994-95 2000

0.25 256 Mbit 1992 1997-98 2003

0.15 1 Gbit 1995 2001-01 2006

Unlike rotating DASD, RAM-based architectures command a very price-elastic market. If the price

decreases, the demand increases. You cannot necessarily stimulate the demand for DASD or tape by

changing the price. The industry-standard DRAM chip has moved from 1 megabit to 4 megabits Note

that the 4-megabit chip has been under development since 1983. As DRAM densities increase, price

decreases along with the physical space required to store information. Thus much higher capacity

DRAM storage devices will appear occupying smaller footprints. This trend should continue until the

point where DRAM-based storage devices will occupy a large portion of the storage hierarchy

currently belonging to rotating and cached DASD.

1-12
MEMORY/MIPS SHIPPED

12

11-

-o 10-

a)

cL 9 -

Q.

.m

r- 8 -

03

n 7 -

6 -

nn

5-

00

$ 3-

>

< 2

A

w

Data, Tables, Code, VLF,

and LLA, Hiperspace,

Data space in memory

2MB

w

MVS/SP

7.5 MB f

f

3 MB J MVS/ESA

__MVS/XA

j/"

/s"

/p

(Projected)

370/ 370/ 3033 3o81 3090 3090S ES/9000 FS

165 168

Historical tracking of the ratio of memory installed per MIPS installed indicates the trend increasing

sharply with MVS/XA (31-bit addressing) and MVS/ESA, effectively 44-bit addressing. The MVS/ESA

capability to place data, and program load libraries and other objects into memory, will continue to

drive the ratio upward, requiring more and larger RAM-based storage solutions. The announcement

of VM/ESA and DOS/VSE/ESA implementing hiperspace and data space concepts into these operating systems will further encourage virtual storage growth. The growth rate grows sharply until

shared expanded storage arrives late in the Summit (i.e., future systems) then moderates slightly.

1-13
CHANNEL TRANSFER RATE

GROWTH PROJECTION

,i.eo

HPPI 100 MB/sec

15_ 1.8 MB/sec

10.0 MB/sec

3.0 MB/sec

1.5 MB/sec I I

CPU _ CPU

FS, ES/9000

ES/9000, 3090J 1

PS/2, 3090,

9370, AS/400

PC

Th,o- ,u.J F,b.rO0,,c ]lca ,o. ]

I 1 I I t I I

1989 1990 1991 1992 1993 1994 1995

The data transfer rate capabilities at all levels of computing will increase much faster in the first half

of the 1990s than they did in the previous 15 years. ESC©N channels now offer up to 10 MB/sec data

transfer rates. Device exploitation of ESCON channels at 10 MB/sec will come more slowly. The

3990-3 DASD Storage Control will be the first device to exploit ESCON channels at ESCON speeds.

Up to 18 MB/sec on the FS series is likely by 1995. The gray and thin blue cables will begin to give

way to serial fiber channels providing increased distance (up to 9 km initially) in the early 1990s. The

HPPI (High Performance Parallel Interface) channels used by large-scale CPUs for scientific processing

will offer attachment of specialized storage devices in the mid-1990s, likely RAM-based, providing

high-performance solid-state storage arrays.

1-]4
:3

"o

O

1._

&.

ol

t_

LO

G,t

LARGE SYSTEMS TRENDS

In the last 25 years, the processing power of large computers has increased at a much faster rate than

the performance capabilities of the I/O subsystem. Since the introduction of System/360 in 1965, we

have seen the capacity of a disk actuator increase 190 times. Processor performance has increased

over 200 times, but the performance of a disk actuator has improved only 4 times. This divergence of

processor speed and the I/O subsystem performance has been the subject of considerable interest,

particularly in the 1980s. During this time, we have seen the introduction of a number of technology

developments to help bridge the gap. These enhancements include solid-state disk, cached control

units, dual port, quad port, actuator level buffers, tape buffers and expanded storage. Despite these

advances, the performance gap between processors and I/O subsystems continues to diverge. More

solutions will emerge, predominately based on DRAM technology, to place data closer to the processor

and remove the performance delays of mechanical devices. The ES/9000 processor announcement

by IBM is a good example of this continually diverging trend -- processor speed (MIPS) nearly

doubled while the speed of the storage subsystem remained unchanged.

1-15
TRENDS - AREAL DENSITY

¢t

O=.=

1000.0

500.0

100.0

50.0

10.0

5.0

1.O

0.5

O.1

0.05

O.O1

O.005

• Bit Areal Density mb/in 2 A _k_...._

• Projected 33g_

3380J • Helical Scan

3380_- • 4MM DAT

3370_, ,_

3350_,, f

3340_rill 3330-11 • 3480

3330-1

1301

350

1960 1970 1980 1990 20_OO

Magnetic recording technology has seen few of the anticipated limitations in the areal density (megabits per square inch) that were expected to occur in the early 1980s. Areal density increases in DASD,

once not expected to exceed 30 megabits per square inch, are now over 60 megabits per square inch

in 3390-type disk drives and are expected to increase to over 500 megabits per square inch by the

end of the 1990s. Laboratory developments of 1 gigabit per square inch have been demonstrated. As

the areal density of magnetic recording continues to increase rapidly, the future role of optical disks in

the large systems storage hierarchy becomes more questionable.

The helical scan tape format, recording data tracks on a tranverse rather than parallel to the edge

of the tape, offers areal densities in the range of 30-50 million bits per square inch and very high data

transfer rates. Helical scan technology should enter the hierarchy at the deep archive level and co-exist

with 3480 chromium dioxide (Cro2) tape format throughout the remainder of the 1990 decade.

1-16
o

,,i

w ,

OPTICAL

WHEN

MAGNETIC/OPTICAL STORAGE

5 1/4" OPTICAL PARAMETRICS vs DASD

OPTICAL HDA 1990 1995 2000

Capacity (GB) 1.0 1.5 4.0

Transfer rate (MB/sec) 0.7 1.2 2.5

Cost ($/MB) (OEM) 3-5 1.30 0.50

J¢

DASD HDA

Capacity iGB) 1,5 2.5 5.0

Transfer rate (MB/sec) 1,9 4.0 6.0

Cost ($/MB) (OEM) 2.0 0,60 0.20

g, oA) FORiJMCX)22 D,_|

Optical disk storage has been hailed as the low-cost mass-storage technology of choice for years. In

reality, optical storage has yet to fulfill expectations. Issues such as standardization, throughput, data

transfer rates and uncertainty of shelf life ('data retention) remain. The areal density of magnetic disk

storage is increasing rapidly, while optical disk areal density has remained relatively the same for the

past six years. The write-once, read many times ('WORM) drives are common in the midrange and

desktop markets, but will struggle to find a mainframe niche. Magneto-optic or erasable optical disks

offer the large systems market the most benefit, but may face a stiff challenge from large-capacity

DASD array storage solutions for the online, large-capacity storage market and advanced automatic

cartridge systems for even larger capacity and less costly deep archive storage. Unlike WORM optical,

5.25" magneto optical has the support of formal standards by the International Standards

Organization.

1-17
I

L_

o

TAPE LIBRARIES

MAINSTREAM APPLICATIONS

CURRENT APPLICATIONS

• Tape Management

• DASD Management

- SMS

- DF/HSM, DMS/OS

- DASD savings

• Job scheduling and rerun

- Improved batch

perlormance

Software development

• Automated recovery

- Online data bases

- Mission-critical data

• Report management/paper/fiche

• Electronic archive

- Campus

- Remote vault

• Automated operations

• - Unattended _ Lights out

• High speed search applications

• Anticipatory staging

- Random access data

- Data set scheduling •

ADVANCED APPLICATIONS

• Network storage

• Deep archive with helical formats

Scientific data

Automation has opened many new horizons for data storage. Far beyond simply automating what

currently exists on tape today, automation has become a primary ingredient in cost-effective storage

management and is enabling the promise of s_,stems managed storage to be fulfilled. Several new

applications listed above have become areas of opportunity providing cost savings and improved

quality of operations beyond prior capabilities. The concept of electronic archiving has been given an

increasedfocus with the announcement of ESCON channel architecture complementing traditional

channel extension methods. A form of image storage, report management, has been enhanced with

a number of software products that allow computer output microfiche and printed data to be stored

on a tape library, viewed at a computer terminal, and printed or sent to fiche only if needed. This new

area of library exploitation greatly reduces distribution, copy and filing costs while improving the

security aspects associated with printed storage. Applications with much promise for automated tape

libraries include anticipatory staging of data and deep archive storage for long term-data storage.

1-18
O_

,4,-¢ O

f,/)_

AUTOMATED OPERATIONS

I

Present _1

'

___ltomated Procelses

Phase 1 2 3

Time =

Console

Message

Recovery

SMS

TMS

Output

Distribution

Operator

Manual

Storage

Pools

Physical

Placement

Burster

Trimmer

Suppress

Auto Reply

Auto

Restart

Space Mgmt.

DF/SMS

Scratch

Retention

Roll Feed

Bar Code

Open

Architecture

D/B Recovery

Appl. Recovery

Performance

Management

ACS 4400

Online Viewing

Selective Print

N

As automated operations becomes a strategic goal for many data processing users, solutions are

appearing which are making companies more competitive, more productive and more profitable.

Automated operations is usually fully implemented in stages and will evolve to include expert systems

solutions to resolve some of the complex, enterprisewide information management issues. The

primary reason for automated operations is improved quality of the data processing organization.

In addition to automated operations, business resumption or disaster recovery planning has

become a strategic goal for many users. Workshops on these areas of advanced data center

operations are available on a worldwide basis from Storage Technology Corp.

1-19
rE

ol

¢,..

ol

t_

O

u)

O==.

ELECTRONIC ARCHIVING

Computer Center

Backup Facility, Vault

!

® t C"anne' r

I . Extension Backup Facility, Vault

r

i

Channel

Extension

Channel t

Extension

Campus or

Hot Site

Computer

Centers

_) Fiber Optic Channel Extender, T3,

or ESCON

The rapid acceptance of library storage products such as StorageTek's 4400 Automated Cartridge

System (ACS) has provided a means for computer users to archive data electronically to a secure,

remote location such as a vault or warehouse. Today, the use of fiber optic channel extensions

provides 3 megabyte per second device attachment. Products such as the 4400 ACS can be located

at distances well beyond the four walls of the computer center by using fiber optic channel extenders,

T3, or ESCON communication lines. The "data vault" provides backup of critical data in a safe location and also can link int_ a hot site or campus computer facility for a quick recovery in case of a

disaster, This trend will expand in the 1990s as the value of information to the corporate enterprise

becomes increasingly more important.

1-20
Progress of Storage Technologies

.._ ACS

,¢_ / I Advanced Robotics

__.-_ o.r_/,_ ::_jTape Cr02, Helical, D2

• • : .

E •_ --_ _ll Optical

/ ¢'_ "b2L_L_"_----_/ =1_ WORM, Magneto Optic

:t% ," -"---' TFH, MR, TFM, RAID + ...

_/__-'_,_. / I_arched DASD DRAM, NVS

/ '----..----.._'_-/._ ._ DRAM, FRAM?

'_.o.__'_'_ "_ "< _"_':--]"''- ie " Expanded Storage

OOo ,. -_ ,

"OOo ¢1__ .S_Z-.-... •_ _..,_Main Memory

,t, _ ,/ ;"J=_ " _l DRAM

-ooo1

I I

. J

- OOOo•

Let's take a look also at a few of the technologies that have merged to help resolve some of the

challenges in the 1990s. The 1980s was the the decade of technology. The 1990s will be the decade

of how we exploit that technology effectively. In the 1980 timeframe, we clearly remember vendor and

customer discussions regarding DASD. Issues centered on such things as the diameter of the disk

platter. How thick is the platter lubrication? How high does the read/write head fly? The answers to

those questions sometime9 influenced buying decisions. Today in DASD acquisitions the issues are

gigabytes per square foot; I/Os per second; availability; cost per gigabyte. The size of the platter really

doesn't have to make a difference, but gigabytes per square foot should.

Notice that main memory presently is priced at about $4,000 per megabyte with an access time'

measured in nanoseconds. Expanded storage has a 75 microsecond access time and is priced at

about $1,500 per megabyte. There remains a major performance and price gap between the memory

technologies (DRAM) and moving or rotating technologies.

Optical storage and tape provide two interesting comparisons. The areal density of optical storage

has witnessed insignificant improvement in the last six years. During this time, magnetic storage has

significantly increased in areal density. Interestingly, the IBM Image Plus system, using a write once

optical storage device, is priced around $2 to $3 per megabyte. Tape libraries, including compression/

compaction, may realize costs as low as 10 cents per megabyte.

New technologies will evolve to fill this gap such as ferro-electric RAM (FRAM) devices. These are

non-volatile RAMs and still under development though expected to be affordable and commercially

available in the 1994 time frame.

1-21
i-

.,o2o

t,/}_

STORAGE HIERARCHY

1995 - 2000

Fi×ed_lvl_dcic; ss

dorn -" - -

a andor_ -

The hierarchy of storage technologies, not devices, in the last half of the 1990s is shown. This hierarchy may be broken down into fixed-media and removable-media segments. Fixed-media storage

will consist of RAM and rotating DASD. Optical disk, once viewed as the heir appar0nt to the

removable-media segment, has given way to automated tape systems that are faster and less costly.

Further advances in the capacity of 3480 cartridge capacity to 1 gigabyte levels and the increased

usage of helical scan formats make magnetic tape (along with magnetic disk) the key technologies

of the 1990s.

1-22
TRENDS - STORAGE

MANAGEMENT EVOLUTION

O= =

o

00_=

t'-

0

,i

E

LL

rE

c

(1)

03 u_

_o

I I I 1 I

"71 "73 "75

03

03 .1-

t_

O3

I I I I 1 I

"77 "79 "81

E "1 , m _ ILl /,/3--103

03 -=° "-n _ ___--

GUIDE 03 o. m

White _,____J"

Paper d _n I

• _ _ I • Repository

o _. _ Expert •

_. _ _ Systems

X_ _//r _ Unattended

[---= _ _ _: EleceroOn;: rali°ns

O3

• Archiving

Automated

Operalions

I I I I I I I I I

"83 "85 "87 "89

The total cost of storage devices now accounts for more than one half of the total hardware expenses

of the typical large data center today. In the early 1970s, storage management meant tape management. With the introduction of the DMS/OS and HSM storage management products in the late 1970s,

storage management expanded its scope to include space management for disks. Since that time,

storage management had been relegated to improving various facets of space management until the

announcement of DFSMS in February 1988. This platform should gradually evolve to include dynamic

performance tuning, storage management for distributed processiqg nodes, networks, workstations,

a DFSMS equivalent for VM and development of a repository to identify objects across all computing

platforms in the corporate enterprise.

DFSMS is a trademark of IBM Corporation

I = i i=

1-23
O_

SYSTEMS MANAGED STORAGE

Programmer/End User i Storage

I

I

Physical

Isolation

I

Storage Management Subsystem

DFP

Data

"- Management

Performance

Tuning

Security

Less Active

Data

Hierarchical

Data

Movement

Administrator

SSD t

._.__ Array DASD

@ DASD

_ Tape

,_ o Service Requirements Storage Assignment

_ (Logical View) (Physical View)

Systems managed storage is a concept that allows an operating system to perform many of the

human-intensive processes involved with space management, performance tuning, availability

management and true hierarchical storage management supporting all tiers of storage. Though in its

infancy, systems managed storage must efficiently evolve these processes to provide the platform for

single-level storage in the last half of the 1990s and achieve an environment that allows "true systems

managed storage:' DFSMS is one of several products that make up systems managed storage.

Presently the DFSMS product provides no performance tuning capabilities or movement of data

vertically throughout the storage hierarchy to optimize performance or space management.

ii

1-24
COST OF USABLE, MANAGED STORAGE

7 3,5x Raw Storage Cost

o 6

_ 2

._ .E

.__ 8 o

lOx

Availability

$2.61

People

Used

Capacity

Raw

Storage

19781980 1982198,,1986 1988 1990 19_2

_. Source: IBM SystemsJournal,1989

The total cost associated with managing storage has declined since 1978 on a per-megabyte basis.

The cost of raw (live) data, plus the costs of unused capacity, people costs to manage the storage

system and additional costs of availability such as backing up data, have increased several times

since 1978 on a per-megabyte basis. The cost of managing DASD, effectively or ineffectively, has

become a primary concern in very large (terabyte plus) data centers and clearly is necessitating the

movement toward much improved storage management facilities. It is estimated that the total cost of

managing disk storage in the 1990s will be as much as 10 times greater than the cost of actual data

stored on DASD. New storage solutions, such as advanced fault tolerant DASD architectures, will

dramatically improve these trends.

1-25
/ DASD USAGE TRENDS

_L _1 I L 17% ) 45,/, .,_ F-- .Allocated/Unused

j ] J _ _ j _ Allocated/Used

_++ __--_ IlL 111 I ( 16%> S1% '

+,+.,,_+++_o... I --"-_ I I I_ / /

_-_.___° I _ I I

'.-++---"o+.+o t_ 38,. _ I

_. _"

=. I

0 _ + +++++

Formal surveys on DASD usage have been conducted since 1978. The net utilization, or the amount

of real data on the average device decreased from 61 percent in the 1978 survey to a low of 45 percent

in 1984. The 1988 survey indicated an overall increase in net utilization to 51 percent. This survey

included single-, double- and triple-capacity 3380-type devices. The single- and double-capacity

devices actually increased in utilization; however, the triple-capacity devices continued the downward

trend. Utilization of the single- and double-capacity devices increased largely due to the higher percentage of caching permitting increased space allocation on cached DASD. Space utilization figures

for 3390-class devices are not presently available though the lack of widespread DFSMS usage to

optimize data allocation on 3390-type DASD may initially inhibit more effective utilization.

1-26
0

-!

0

L_

0

01

0

O0

PERCENT OF DATASETS

BY DATASET ORGANIZATION

VSAM

Sequential

72.0%

BPAM

16.0%

Other- 2.5%

- 1.4%

ISAM - .1%

As a follow-up to the previous chart on DASD space allocation, the percent of DASD data sets by data

set organization reveals a correspondingly high percentage of sequential data sets. VSAM and SAM-E

(sequential) data set organizations are strategic while partitioned data sets will fold into VSAM format

as ESA/390 evolves. Other data sets such as graphics access methods, direct access files and even

ISAM will exist as they are today. This profile again reflects the results of extensive tape-to-disk

migration activities in the 1980s.

1-27
0

"10

0

O.

t_

0

oO

w >.

t_

PERCENT

BY DATASET

VSAM

29.3%

OF SPACE

ORGANIZATION

BPAM

Other 14.8%

Sequential

45.0%

- 5.3%

Direct- 5.1%

ISAM - .5%

Storage management has increasingly focused on DASD in the last few years, primarily due to the

criticality of data residing on DASD. At the end of 1988, sequential data had grown to include 45 percent of allocated disk space• This was primarily a result of the large number of tape-data-set-to-diskconversions in the early 1980s, occurring for the lack of any successful automated tape library system

available to mainframe users. Tape data sets requiring rather quick or frequent access could not often

withstand erratic human tape mount times.

This DASD profile, as a result of the 1980s strategy of "put it all on disk;' has become a significant

cost savings target for automated cartridge systems in the 1990s.

1-28
TAPE COMPRESSION/COMPACTION

TAPE DATA SET PROFILES

100

9O

_- 8O

_" 70

_ 60

I-- a)

oor)

_co 50

¢) _-"

•_E3 40

ao

,,_ _ 20

10 }i °

Cu-mu Ial___0i_l-Ta-_-e_D a-_-S ets

vs Data Set Size (MB) 88.56

80.14

75.5

70.14 __

61 72 "

55.56

51.26

0 7 1 - 3.5 - 10.6 3 - 46.2 96.1 - 195.8

.7-2.1 3.5-7.1 10.6-21.3 46.2-96.1

Data Set Size(MB)

A survey of tape data set sizes indicates that the vast majority of tape data sets are very small.

70.14 percent of the tape data sets in the survey are under 21.3 megabytes in size. Even with the

tape-to-disk conversions of the 1980s, many small tape data sets remained on tape and became

obvious targets for automation. While 11.44 percent of the tape data sets occupy over one 200MB

3480 tape cartridge, the majority of these data sets are backup applications using processor datacompression functions.

1-29
f,tJ_

TAPE COMPRESSION/COMPACTION

TAPE DATA SET PROFILES

50-

40-

Q)

E

o)-"-- 30 -

,._ t'n

_'_" 20 --

a

10 T

O _

Data Transfer Time at 4.5MB/sec

vs Data Set Size (MB)

49--

E

24

11.5

_ L___ [__"

0-'.7 -10.6 !21.3-46.2

•7 - 2.1 3.5 - 7.1 10.6 - 21.3

Data Set Size (MB)

96.1 - 195.8

46.2 - 96.1

The tape data set size survey is equated to data transfer time for each classification of data set on

a 4.5 MB/sec channel using bus and tag or even ESCON. The 21.3 MB tape data set takes approximately 5.1 seconds to process once mounted. Assuming a 24o-1 data-compression factor, a total

time of 2.55 seconds would be used to transfer the 21.3 MB data set. This minimal gain from compression/compaction is often lost by the variability in manual tape mounts resulting in minimal, if any,

throughput benefit for 70 percent of the tape data sets. By the early 1990s, nearly everything written

to tape will be compressed. Like 7-track, 9-track, NRZI and GCR in the past, tape data compression

will be another format for tape data recording.

1-30
COST-EFFECTIVE STORAGE PROFILES

Allocated Space

Cost Effective

Allocated Space

% of

Total lOs

,_Solid-State DASD 30%

/ _ [ _ /161/°_achedDASD 50%

/ 2n!ine - _ / 31% _Capacity DASD 15%

/ o tu, ay_ __>/ 52o/o _Nearline/Tape 5%

1980s

-_ • Technology

__o_!• Get decisions the right data

o _ in the right place

1990s

Business

decisions

Get the right data

in the right place

at the right time

Using advanced data storage placement methodologies such as CPIO (Cost Per I/O) analysis, it is

possible to determine the most cost-effective location in the storage hierarchy. Using the size, performance and storage cost per I/O to determine optimal data set placement, studies indicate that online

storage users today may not be cost effectively utilizing online storage. Typically, 1 percent of the

space allocated in online storage generates 30 percent of the total online los. This small but highly

active group of data sets is most cost effectively located on solid-state disk. At the other end of the spectrum,

a little over half of the data allocated on DASD today is more cost effective on automated cartridge

systems or manual tape. Storage management in the 1980s stressed getting the right data in the right

place; storage management for the 1990s will stress getting the right data in the right place at the

right time.

CPIO is a proprietary software tool from Storage Technology Corp.

1-31
notes

1-32
N93-13133

OPTICAL DISKS BECOME ERASABLE

Dr. Robert P. Freese

President, Alphatronix, Inc.

Research Triangle Park, NC

Discussion

$

Optical Recording

How Does it Work?

Why All the Fuss?

State of the Industry

Sample Applications

Future Directions

PRECEDING PAGE 13tANK NOT RLMED

1-33

OPTICAL DISK AND TAPE TECHNOLOGY

Dr. Robert _

DR FREESE: Thank you. Good moming. Does everyone want to stand up and take a

quick break?

(Participants stand up and stretch)

DR FREESE: Okay. Now, it is I0:00 and let's begin. Just a quick fix.

What I would llke to do today is spend a few minutes talking about and giving you an

overview of the status of the optical recording industry.

(Showing of slides)

DR. FREESE: I have tiffed this particular overhead optical disk '"oecome erasable."

"Rewritable" is a technical term.

(First slide)

In today's presentation, I would really like to take an end user perspective, not so much

of a technology perspective; and I would also like to take a more practical approach to the

status of the industry, which is to say we have all sat through presentations and talks like this

over the last decade and heard about an the wonderful things comlr_ up.

But I would really llke to take a more practical approach: What can I buy now? How do I

use it? Why do I use it? And what am I going to see in the immediate future?

I would like to focus first of an Just on the status of the optical recording industry,

review how it works, talk about why all the interest and why all the fuss, go through a few

sample applications and a few future directions.

(Change of slide)

DR. FREESE: Of course, everybody always asks me. There are three types of optical

recording systems: the so-called read-only, the so-called write once, and the erasable.

(Change of slide}

DR- FREESE: Read onlys, Just like the name implies: You can read the disks, but you

can't record on them, and you can't write on them. The first implementations of this were llke

video disks; and in fact, I believe that you at NASA have used as data distribuUon mechanisms

in the laser disk format.

(Change of slide)

More recently, CD ROM and CDI have been introduced in the smaller format and are

starting to see widespread acceptance.

(Change of slide)

DR- FREESE: Probably the most questions I get are relative to WORM, or the write-once

optical disks. WORM stands for 'Xvrite once/read many times." These were introduced in 1982,

1983, and 1984--this type of time frame. Their marketplace is extremely smaU; we have seen

that. It is really a precursor to the rewritable marketplace.

PRECEDING PAGE BLANK NOT FILMED

1-35
Optical Recording Systems

Three Types:

* Read Only

* Write Once (WORM)

* Erasable

Read Only Optical Disks

Introduced: 1979

Function:

Markets:

Application:

Read (only)

Music, Publishing

Compact Disk (music)

CD-ROM (data)

CD-I (data)

Interactive Videodisc

Write Once Optical Disks

Introduced:

Function:

Market:

1983

Read and Write

Precursor to Re-writable Marketplace

Other ??

Applications: ??

Standards: No

1-36
Applications for WORM. Now that rewrltables are here, there are very, very few. People

constantly misunderstand the fact that a WORM is for "archival purposes." AWORM Just

doesn't last as much as an erasable disk. And you can give me a WORM disk today, and I can

alter the data for you--reaUy simply--and you will never know.

(Laughter)

DR. FREESE: So, in terms of the market and in terms of the applications, a very, very

small market--very, very, very small. And many companies have found that out, like STC, and

got out of that business.

(Change of slide)

DR. FREESE: Erasables tend to be a little bit new, introduced officially in 1988. Of

course, with an erasable optical disk, you can do all the things that you normally associate

with magnetic disks, floppy disks, hard drives, Winchesters.

There is an extremely wide variety of markets, and the applications we will go through

in Just a second. But you can use them Just like magnetic disks. A lot of people say they are

erasable or rewritable compact disks; and every once in a while, somebody will use the term:

It's Just llke a random access tape.

(Change of slide)

DR. FREESE: Optical disks all work the same. You start out with some sort of laser

source--a laser diode or whatever--take that light, put it into an optical head, and focus it onto

a rotating disk memory.

You use that same laser beam to go back and read the information off the disk.

(Change of slide)

DR. FREESE: Well, that was simple enough. Why all the fuss? Why all the fuss is

because it combines-- uniquely combines--these particular attributes. You get a large storage

capacity, which we will talk about in a minute. The disks are removable. You have increased

reliability; every time you talk about more data and more capacity, reliability gets more and

more and more important.

I am reminded of the time that I lost my business plan on a floppy disk, and I can't tell

you why; but anyhow, I Just lost it. The disk got corrupted somehow. And I was really mad and

angry for about a day because it took me about a day to redo the business plan from my memory

back onto the computer.

Suppose that was a little optical disk; looks Just like a floppy disk, about that big

[demonstrating]--only that it is going to hold 1,000 floppies. So, now, if you lose the data on

that disk, that's not one day that you are going to be upset; it's 1,000 days.

So, we'U talk a lot about reliability associated with optical recording systems.

You get a random access feature associated with the disk; we will talk about the

archivabflity and key features associated with archivability--one of the main reasons why

NASA is using these disks today for some of their archival storage.

we'n talk a little bit about erasability, and I want to concentrate also a great deal on

international standards.

(Change of slide)

1-37
Erasable Ovtical Disks

Introduced: 1988

Function: Read, Write and Erase

Markets: Medical

Imaging

........ En_neering .............

Security

Accounting/Banking

more...

Applications: "Just Like Magnetic Disks"

"Erasable CD's"

"Random Access Tape"

Standards: Yes

How Does It Work?

III

Magneto Optic Technology

Erasability of Magnetic Recording with the High

Density, Reliability, Removability of Optical Recording

1-38
Why All the Fuss?

Combines:

* Large Storage Capacity

* Removability

* Increased Reliability

* Random Access

* Archivability

* Erasability

* International Standard Media

Large Storage Capacity

650 to 1,000 MBytes per 5.25" Disk

16,000 to 93,000 MBytes per Jukebox System

"Gigafloppy"

Mainframe Storage on Desktop -- Removable

1-39
DR. FREESE: In terms of the large storage capacity, typically you are looking at 650

megabytes on a 5.25 inch disk; that is user available storage capacity. Within the last year or

year and a half, there are robotic systems, near-line storage systems; and they will provide you

up to about 100 glgabytes per storage system by as many systems as you want.

A lot of people who use these disks refer to them as a "gigafloppy." The people at NASA

Goddard, for example, use the disks to store the VOYAGER I and VOYAGER II data. Imagine

sitting at a work station with VOYAGER I and VOYAGER II data--all the data, I understand--on

Just a few disks on the desk-top.

Any time you want to access any of that data, Just pull down the disk, pop it in, and

away you go.

(Change of slide)

DR. FREESE: The disks are removable. This is the part everybody always forgets. In

fact, I can't tell you how many times a customer has come back and said: By the way, did you

know these things are removable?

(Laughter)

DR. FREESE: It's a disk; you use it Just llke a floppy disk in that respect. They'll say:

Sure, yes, I sold you the system. I knew they were removable, and it says so right there in the

literature.

But people aren't used to removable data storage; so, think of it. You are sitting there are

your work station; you need disk access, disk storage. So, you fill up your optical disk, or you

fill up your hard drive. What are you going to do next?

wen, you can go out, and you can buy another hard drive. That is sort of an expensive

solution. Or you can pull the optical disk out and Just pop a new one in and set the other one

aside.

(Change of slide)

DR. FREESE: So, at a work station level, what you find is virtually "infinite" storage

sitting at your fingertips. Write a system once; Just feed cartridges in and keep them right in

front of you.

Beyond that, people discover once again the disks are removable. If you can keep them

on your shelf, you can keep them on your Ufle shelf. You can keep them in your salt mine vault

in the mountains in the western region of the U.S. if you want.

(Laughter)

DR. FREESE: You can even take your data and say that university up in Michigan or a

university in Ohio wants to take a look at that data, do a disk copy. Federal Express it; send it

to them. If the guy happens to be on your local area network, then you can send it across the

network if you wish.

My experience is that most of the tlme they are not linked to you. So, Just do a disk copy

and mall it overnight to them.

You have got the message in terms of the use; and by the way, if you stop by tomorrow,

you can see one of these devices and play with it all you wish. You have, in essence, a removable

hard drive.

(Change of slide)

1-40
Removability

* Portable Cartridge

* On-line Storage

* Off-line Storage

* Back-up

* Archival

* "Removable Hard Drive"

Increased Reliability

Non-contact "soft" Laser Beam

No Head Crashes

No Wear

No Tribology Issues

Eliminates #1 Failure for Conventional Media

Increased Reliability

* Active Layer Buried Within Glass Substrate

* Dust and Dirt Out of Focus

* Reduced Susceptibility to Contaminants in Environment

* Protective Cartridge

1-41
DR. FREESE: It is random access. I spent an hour on the phone yesterday with a guy

saying: Exactly what does this thing look like? He was a PC user. And I said: Gee, it looks Just

llke a Drive A. You plug it in. My secretary can take a system out of a box, not even reading the

instructions, install the thing, get it up and working in 20 minutes. The worst part about it was

that she had to teach herself which end of the cartridge goes in the slot and where the button is

to push it out, to get the cartridge back out again.

It's a disk; it's a regular disl_ You use it just like a regular disk. There is nothing for the

user to learn or to forget. There are no new commands for you to learn; there are no new

commands that you need to forget. Can you do disk copy on it? Sure.

DR. FREESE: It is rewritable. I find that people in the marketplace use the term

erasability; but the technical term is rewritable, which is to say that you can delete a file and

recover that space.

You can delete a file on the WORM systems, but you don't get the space back and the file

will go on. And if you give me about two minutes, I can delete a file so that you never even knew

it was there; there is no traceable record associated with the WORM system. All that is done on

the software side.

And so, if you wish, you can put together a so-caned rewritable system such that you can

only record it once, and you can't ever record that spot again. So, you can have all the

functionality of WORMs without any of those disadvantages.

People constantly ask me: How many times can I erase this thing? Or:. How many

times can I rewrite this thing? We actually know of no limit. The highest number that I know

of that has ever been tested on a single track is 30 million times of rewrite/erase cycles.

You typically don't get that many cycles with tapes, floppies, or hard drives today; but

the limitation is not the recording mechanism, it is associated with the tribology. You get a

head crash, or you get some friction. You get some dust on a disk.

DR. FREESE: Everybody knows that optical disks come in sandwiches, llke a peanut

butter and Jelly sandwich; you use the peanut butter and Jelly layer as the recording layer. So,

the actual physical recording layer is buried; it is buried underneath either glass or it is buried

under bullet-proof glass. That makes it pretty tough. It doesn't make it totally perfect.

You can give one of these disks to your dog, and your dog can chew it up; and you'll lose

your information. However, what this means is that the information surface is buried and that

things in the environment which play a role--dust, dirt, fingerprints, sea water, whatever--stay

off the information surface.

The information surface remains buried and protected; and this has great implications

relative to our data storage. Put a disk on the shelf for ten years and you still want to access

that data--great. In this particular case, you might even have to blow off some dirt ff you want;

but your data will still be there.

DR. FREESE: If you have got all this data and you have spent a lot of money obtaining

that data in the first place, you want it to last for a while. You don't want it to last Just a couple

minutes or even a couple years. You want it to last for a very, very, very long period of time.

So, let's talk about the archivability or the stability of these types of disks and where

you may end up using these instead of some other type of technology.

The first thing is what we Just talked about. I don't know what a soft laser beam is, to

tell you the truth; but you have a noncontact method of recording. You are not rubbing any two

things together;, you are not rubbing any two surfaces together.

1-42 i
And so,becauseof that, youdon't haveany head crashes; and you don't have any wear.

You totally get rid of the tribology issues, for which there is an entire panel--I believe either

later today or tomorrow--to discuss. Those issues are gone.

But those are your number one issues associated with conventional magnetic recording

systems today. Because those are gone, you have increased reliability associated with these

systems.

DR. FREESE: In the magnetic-optic approach, which is pretty much the standard

approach today, people always ask: How about accidental erasures? In fact, the people in

Washington, D.C. are always asking me: Can you take the media on the subway?

And in fact, in 1984, I had to do some tests, where I actually carried the media on the

subway for a few governmental agencies.

It is important to realize that in the magnetic- optic approach, it's true that the disk has

magnetic properties; but the coercivity of that disk, or how stable those domains are--how

much force it takes to accidentally erase your disk--is extremely high.

(Change of slide)

Your typical, conventional magnetic recording media today is somewhere between 300

Oersteds and maybe a little over 1,000 Oersteds. My son's magnet is stronger than that. And if

my son sets his magnet on top of my video tape. the information is gone.

With erasable optical disks, you have coercivities that are in the hundreds--or I should

say, in the tens of thousands of Oersteds. or tens of thousands of Gauss. Those types of

magnetic fields, ladies and gentlemen, don't exist in the normal environment.

There are a few Government agencies you can go to that can produce a field that strong;

but typically, you can't run into this in the environment. So, you can indeed take this disk and

set a magnet on it if you want; and it won't do anything. It is very, very, very stable,

And yes. it can be sent through the mail; and yes, it can be sent through the airport

security checks.

(Change of slide]

DR. FREESE: Those of you who are familiar with the removable media systems, or

removable Winchesters, that were a little bit more common at the beginning of the 1980s, are

familiar that you could take and remove the disk pack and set it on the shelf. And if you did so

and then took that and put it back in three months later or six months later, you couldn't

retrieve the information.

That issue also is addressed in the optical recording systems. You couldn't retrieve that

information because you got some misallgnments in the head. and the tracks no longer lined

up again.

With the optical disks, the optical disks are all pregrooved--litfle tiny grooves. Just like

your record album grooves--sitting in each disk. With that groove, you can have servos which

follow precisely on that groove. Now. big deal--what's the importance of this to the end user?

The importance is that these disks are removable, remember. They are removable--if

you want to put them on the shelf, if you want to put them in an archival vault, if you want to

potentially send them to a guy in Ohio, you can. He has a different system than you do; and

now, you have to deal with system to system and media to media fluctuaUons.

1-43
Increased Reliability.

* Extremely High Coercivity Media

(5,000 to 50,000 Gauss)

* Most Magnets too Weak to Affect

* Accidental Erasure Due to Magnetic Fields Difficult

* Can be Sent Through Mail and Airport Security Checks

Increased Reliability.

Each Disk Hard Sectored with Physical Grooves

(tracks)

Tracking Servo Maintains Alignment to .1 _M

Focus Servo Maintains Alignment to .1/_M

Track to Track, Disk to Disk Variations Corrected by

Servos

"Mirror" Block Corrects DC Servo

Position 2400 Times/Minute

No Long Term Drift

Enables Media Interchangeability
Well, with these pregrooves, you can send them the media, which isn't perfectly to spec;

and his system will go back and line up on that groove and store and retrieve the information

in that reliable way.

Every once in a while, somebody in the audience is quite familiar with the servo

mechanisms; and he says: That's great; servos will solve your problem, but your servo may

drift after a while so that your laser beam isn't dead nuts on the groove any more; it's dead nuts

on the edge of the groove. And isn't that a problem, too?

WeU, that problem is solved also in the preformatted structure of the disks with what is

called its "mirror block." What happens is: Once a revolution, the D.C. position in focus and

tracking is corrected, so you get rid of long-term drii_, too.

The bottom line is: You can remove these disks, and our customers do it all the time.

Pull the disk out of your drive and pop it into somebody else's drive.

(Change of slide)

DR. FREESE: People always ask me about life; and to tell you the truth, the media has

not been around long enough to actually quote field experience, other than for the past, say,

four or five years.

People do extrapolation tests and determine the chemical stability of the disks and

predict lifetimes as a result of this. Outcomes of the erasable optical disk are very, very good. I

won't sit up here and quote you the numbers of the technical people because you won't believe

them.

But I would like to give you a feel for what is a little bit different in the optical disks. I

think you heard in the introduction that I used to be in charge of 3M's WORM activity at one

point in time; and we used to do comparisons between the WORM disks and the erasable disks.

The erasable disks almost always won in terms of their longer life, and usually by about a

factor of 10. They did so because the erasable disks are sell- passivating. What this means is

that if you took a WORM disk and drilled a hole in it and put it in a very corrosive

environment, eventually that corrosion would eat up the whole disk. STC constantly saw

those tests.

If you do the same thing with an erasable optical disk, you can cut a hole in it and the

corrosion will grow for a couple microns and will stop; it will atop growing. It is because of this

self-passivation mechanism. You are familiar with them: your car bumper.

Your car bumper is made out of chromium, and chromium is a really reactive metal. It

is right up there; it is one of the most reactive metals known to man. So, how come your

chrome bumper stays around for so long? It does so because as soon as that chrome bumper is

formed, there is a layer of chromium oxide which is formed on the outside; it oxidizes and

forms chromium oxide.

Chromium oxide is really tough stuff. It's right up there with cubic zirconium in terms

of stability. And so, that chromium oxide layer protects the rest of your bumper. Now, if you

get in an accident and scrape that layer off, what happens? Well, a new layer forms

immediately. And that same mechanism is present in the erasable optical disks. So, you have

a very, very, very high or very long archival IEe; commercial people Just say greater than ten

years. At the same time, the magnetic domains are very, very stable.

If you are familiar with magnetic domains and the stability of magnetic domains, you

know that on magnetic tapes, as an example, the domains move around. Well, when the

domains move around, you are losing data.

1-45
Random Acces_

* Fi!e Directory Structure Stored

* "Random Access Tape"

* Instant Restore Applications

1-46
And ff you have ever taken an audio tape, you can hear this. You hear the music right

before it starts; that's the domains moving. That is bleeding.

The ability of a magnetic media to bleed or lose its domains or have the domains move,

all else being equal, is inversely proportional to the coercivity. So, here you are talking about

coercivities that are ten to a hundred times higher and more stable than your conventional

magnetic disk.

(Change of slide)

DR- FREESE: But the biggest thing in our compatibility is standards; that is really the

issue, ladies and gentlemen. It's not Just the disk that will last because some other guy is going

to get up here and say: Well, my disk lasts Just as long as your disk The issue is ten years from

now, 20 years from now, 30 years from now, when you pull that disk offthe shelf or out of your

vault, or you are wanting to call back up the old APOLLO data, or my son is going to call up the

old APOLLO data, the number one issue is going to be: (1) Is that disk still intact? Yes, it will be

intact. (2) Is the information still on the disk? Yes, it's still on the disk. But hey, are the

players going to be around?

Are any of the companies that sell you the systems today going to be around then?

That's your number one issue. Now, ff you are looking to store your data for a long period of

time, what is your best bet against this problem? Nobody can promise that they are going to be

here 30 years from now.

Your best bet is to build standards. So, if that company is not here, at least some other

company is. You see this today in all the 1 inch tapes or the 1/2 inch tapes or the 3/4 inch

tapes, you know, the 6250 BPI tapes and the 1600 BPI tapes.

Why do people still use these tapes for their standards? People sell equipment, and they

maintain equipment, which enables you to play those tapes.

DI_ FREESE: In the optical disk world, it took us eight years to get a standard. That's a

long time, believe me. Anyhow, the standard is done. There is an international standard; it

has been embraced by all four international standardization committees, and it is in the 5.25

inch form factor.

There are no standards for form factors larger than 5.25. So, if you are going to store

your data for archival purposes and you are looking for standards, the 5.25 inch form factor

standard is done; that has been done for two and a half years now, endorsed by all of the

international bodies--ISO, ECMA, ANSI, and even the classic Japan Study Committee No. 23.

This not only gives you multiple sources of commodity media, but it addresses the main

issue: standards and open systems architecture, which will potentially enable you to retrieve

your data. Store it on the disks now; retrieve it ten years from now. Retrieve it 15 years from

now; retrieve it 20 years from now.

DR. FREESE: There are disadvantages to raise about optical recording systems; they are

not all things to all people. And Ikn the last guy who is going to get up here and say these

systems are going to wipe out tapes or are going to wipe out hard drives or wipe out DRAMs.

All these technologies are going to ct_xist. They each have their advantages; they each

have their strengths. And the key will Just be putting them together in a hierarchy.

Disadvantages associated with this industry. The technology typically requires fairly high

manufacturing tolerances. So, the cost for the home user, the clerical station, is too much; it's

too high.

(Change of slide)

1-47
Archivability

Self Passivation Mechanism

Expected Life > 10 Years

High Coercivity Stabilizes Magnetic Domains

Short Term or Long Term Memory

#1 Failure: Cartridge Abuse

International Standard Media

*ll 5.25" Form Factor

ISO, ECMA, ANSI, JC23 Ratified

Multiple Sources of Commodity Media

Random Access to Archival Data

Mainstream User Acceptance

1-48
Erasability.

"Just Like Magnetic Disks"

"How Many Erase Cycles?

SYSTEM # CYCLES LIMITATION

Tape

Floppy

Hard Disk

Optical

1,000's Friction, Wear

100,000's Friction, Wear

100,000's Tribology, Head Crash

10,000,000's ???

Disadvantages

* Technology Requires High Manufacturing Tolerances

* Cost too High for Home User, Clerical Station

* New Technology, Long Implementation Cycle

Not a Winchester Replacement

(not fast enough for some applications)

1-49
The cost relative to a hard drive is not a valid comparison. You will hear speakers

constantly sit there and say: Let's compare a hard drive with an optical drive. Okay. They are

almost two different animals.

A hard drive comes with a fixed capacity; it's a high performance device. An optical

drive comes with virtually infinite capacity; you Just keep on feeding those cartridges in there.

It's a removable device. They are both disks.

One is not going to replace the other; and the other is not going to replace the one. Those

things are going to coexist.

But it is a new technology; the industry is just starting. And I would Just like to remind

everybody that the optical disks are not necessarily a Winchester replacement or a hard drive

replacement, nor are they necessarily a tape drive replacement.

But they can combine the best features of all these creating "a random access tape" or a

removable hard drive.

(Change of slide)

DR. FREESE: In terms of where the industry is today, I_l start off with the smallest size.

3.5 inch subsystems were Just announced, and the media standards are in essence completed.

This is a this year type of activity. 3.5 inch is going to hold 127 megabytes on a disk; it will be

about $2,000 to $3,000 a subsystem. And really, this is aimed at the PC world.

Having addressed NASA audiences before, 127 megabytes a disk, I don't think, is quite

enough capacity for most people sitting in the audience. But the 3.5 inch disks have just been

introduced; and so, you have seen many announcements, I think, within the last three months

associated with these.

(Change of slide)

DR. FREESE: In terms of system solutions, 5.25 inch and mbotlc systems, or so-called

Jukebox systems, offer really high capacity systems, and complete system soluUons. You the

user don_ have to know anything about how this device works; but you simply use it on a PC

Just like a big Drive A. You use it on a DEC Just like another DU device. You use it on a Sun

microsystem Just llke another SD device.

It is totally transparent, no new commands to learn or old ones to forget.

You have soluUona for al_ost all your popular computers nowadays, an entire line of

DEC computers, the DEC network, all your Sun domputers and Sun Spares.

DR. FREESE: The old Suns, the Sun NFS network, the new IBM RS6(X)0s, all your PCs

and their clones, the Novell networks; in the graphics industry, you often run into Scitex

whisper stations, Macintosh, Appletalk.

(Change of slide)

So, you have got complete storage systems for almost all of your mainstream computer

systems.

(Change of slide)

DR. FREESE: State of the industry for 5.25. Those standards are complete and being

implemented worldwide. Commercial products began about two to two and a half years ago,

where we talked about 650 megabytes as the increment on a cartridge. Put as many cartridges

in your system as you want.
State of the Industry: 3.5" Subsystems

Media Standards Complete

Commercial Products Begin 91-92

127 MByte/Disk

5-10 MBits/sec

30-50 msec Average Access

$2,000 - $3,000/Subsystem

P.C.'s Only

State of the Industry: 5.25" Subsystems

* International Media Standards Completed

* Commercial Product Shipments Began 8/88

* 650 MBytes User Available/Cartridge

* 5-10 MBits]sec

* 30-100 msec Average Access

* $4,000 - $7,000/Subsystem

* First Applications Workstation Oriented

1-51
Present Status: 5.25" System Solutions

* COMPLETE SYSTEM SOLUTIONS EXIST FOR

MOST COMMON COMPUTERS

E.G., ALPHATRONIX INSPIRE SERIES AVAILABLE

FOR :

DEC VAX COMPUTERS

DEC MICROVAX COMPUTERS

DEC VAXSTATION WORKSTATIONS

DEC DECSTATION (RISC BASED)

WORKSTATIONS

DECNET NETWORKS

SUN SPARCSTATIONS, INCLUDING SPARC 1

AND SPARC 2

Present Status: 5.25" System Solutions (cont)

SUN 2,3,4 WORKSTATIONS

SUN NFS NETWORKS

IBM RS6000 WORKSTATIONS

IBM PC-AT AND PC-AT CLONES

IBM PS-2

NOVELL NETWORKS

SCITEX WHISPERSTATIONS

APPLE MACINTOSH COMPUTERS

APPLETALK NETWORKS

1-52
People who use Sun computers quite often sort of discover the removability aspect. Sun

people, in particular, are constantly running out of disk space. So, when you run out of disk

space, pop it out and put a new cartridge in; and you have another 650 megabytes.

Looking at about 5 to I0 megabits a second on our optical drive, 30 to I00 milliseconds

of average access time; it costs about $4,000 to $7,000. And an awful lot of the 5.25 inch are

really work station oriented. You see this in your Earth Resources in your NASA applications,

where NASA may receive the information from some satellite orbiting; but there are an awful

lot of people who do analysis on that information, universities in particular. So, NASA may

pull the information down on DEC systems and then want to distribute these systems to their

PC customers, ff you will.

(Change of slide)

DR. FREESE: So-called Jukebox systems or auto changers, robotic loaders. You can

take these 5.25 inch disks and stick them in a rack essentially and have an auto changer, albeit

a very, very fast one; and now you Just simply expand by the number of cartridges the amount

of on- line data you can get.

So, typically in a little box about yea big [demonstrating], you are looking at about I00

gigabytes or so of on-llne disk random access storage.

Commercial products began shipping about a year and a half ago. You can get as small

as you want I guess, but anyhow, almost up to 100 gigabytes, user available on the system.

The speed of the robot typically is quoted in a few seconds.

Today, there are mostly vendor unique solutions in the Jukebox arena. Be very, very

careful about this because if your application is archivally oriented, do you want to store your

data on an ISO standard disk using nonstandard disk directory structures?

Do you want to bet your database on one company? Most people say no. If the answer is

no, then make sure you have an open systems architecture solution. Make sure that that disk

is always standard, not proprietary.

If you are on a DEC system, make sure your disk is always a standard DEC disk; it is not

a vendor unique disk.

Make sure that you can take that disk and send it anywhere in the world you want, and

anybody can read and write to it, following the standards. Again, you have got your most

popular platforms.

Where is the state of the industry in optical tape? I didn_ want to preempt the talk by

Bob McLean tomorrow from ICI; but anyhow, let me review very quickly optical tape.

(Change of slide)

DR. FREESE: The advantages of optical tape are mainly optically derived; that is, there

are very, very high densities that you get associated with optical recording and the fact that you

are using a laser beam to rewrite and erase.

You can make tapes basically as long as you want. Optical tapes typically talk about

gigabytes and sometimes even terabytes on a given reel of information.

(Change of slide)

1-53
State of the Industry: .lukebox Systems

* Commercial Product Shipment 89

* 6 to 93 GByte/System

* Disk Exchange - 2-3 Seconds

* Mostly Vendor Unique Solutions

* Some Open System Architecture Solutions

e.g. "Alphatronix Inspire"

* Dec, Sun, PC, Macintosh, IBM Platforms

* Decnet, N.F.S., Novell, Apple Talk Networks

Optical Tape

Advantages: Mainly Optically Derived

- Same High Density as Optical

Higher Capacity: Gigabytes to Terabytes

Optical Tape

* Disadvantages: Mainly Tape Based

Tape Stretch/Break

Tribology/Friction

Contact Recording

Environmental Stability

Non-Random, Sequential Access

i-54
DR.FREESE:In a nutshell,the disadvantagesareassociatedwith the factthat it's a

tape. Tapesaresequentialaccess;tapesbreak;tapesareflexible. It is a contactmethodof

recordingbecausenowyouhavegotto spoolyour tapes.Youhavesurfacesthat arerubbing

now. So,youhaveall the issuesassociatedwith tapesthat needto beaddressed.

(Changeofslide)

DR.FREESE:In termsof applications,I wouldllke to talk abouttwo in particular; but

havingtalked with NASAGoddardfor a coupleof yearsnow,this is oneof your most common

issuesthat I havebeenableto discern.

Andthat is: Hereyouhavethis disk: it stores650megabytes.Great. You can put your

VOYAGER I data on it; you can put your MAGELLAN data on it; you can put your shuttle data on

it. You can put your images on it.

But you have so many people who want to analyze that data; and NASA has so many

relationships with universities and private corporations and is constantly shuttling this data

around. They have a really big problem, and that is that I may be NASA and I store my

information on a DEC system; but the guy who is going to analyze that data is sitting on a Sun

system. Well, the disks are portable; so, I can take my DEC disk and give it to my Sun guy. And

say: Here, here's the data; go ahead and have at it. Except that's a Sun disk; he's on a Sun

system, and that's a DEC disk. Those two thirds are incompatible.

Another example of that is: I'm NASA and I sit down at a DEC system, sending my data

out to universities. The people at the universities are using PCs to analyze their data. Can you

take a DEC disk and put it on a PC? The answer to that question obviously is: No, you canl.

See, now, the optical disk enables at least that possibility because you can store the

information on that disk: it is high capacity, and you can ship it around because it's

removable.

(Change of slide)

DR. FREESE: Bypass is a solution to that problem. Bypass is an application soflware

program which has been designed explicitly for this problem. And what it enables you to do,

Just like the picture implies, is that you can sit on a PC machine using DOS and access standard

DEC fries or standard DEC disks.

And so, for the first time, you_,e got the possibility of a universal storage medium. You

in NASA go ahead and store your information on either DEC, Sun, or PC systems; and that

information can be distributed to anybody else who might be on a DEC, Sun, or PC system, at

all times keeping the disk in standard file structure format.

So, you don_ get any disadvantages.

(Change of slide}

DR. FREESE: So, with Bypass, youX, e got the potential application of a universal

storage medium, adhering to the internaUonal standards, adhering to the file structure

standards at all times. At no time do you have a unique disk--a unique NASA disk, a unique

Alphatronix disk, a unique anybody's disk

The cartridges are easily interchanged; Just puU them out from one and stick them in

the next. And there is nothir_ for the user to do; he Just simply has access to those files.

DR- FREESE: Bypass then is available for VHF, Sun and DOS as of today--oops, I see we

are going to do .MAC in the future.

1-55
Optical Tape

Status:

See Wednesday Talk

Sample Earth Resources Applications

* Voyager I, II data analysis (NASA Goddard)

* Magellan Image Analysis (NASA Goddard)

* Space Shuttle Mission Photography

(NASA Huntsville) (Hughes)

* Weather Satellite Photos/Analysis

(NOAA) (Fleet Numerical)

* Oceanographic Mapping (Woods Hole, Oregon State)

* Data Distribution

(Marshall SFS, USSD, JPL, TRW, Aerospace)

1-56
Rewritable Optical Disk:

The Universal Storage Medium

International Standards Adopted and Implemented

Cartridges Easy to Physically Interchange Between

Hosts

Bypass Platform Dependent File Systems

Requires No Modification to Access Data on any Host

Data Interchange Using Optical

A Solution Presents Itself:

* Rewritable Optical Technology

* 650 Mbytes per Cartridge

* Easily Portable

1-57
Relative to an archival application, this is also sort of interesting because there is a

constant migration of computer systems, a trend that I think everybody in the room can

identify. What a person used to do on a mainframe, he now does on a work station. What he

used to do on a work station, he is now doing on a PC. So, tell me: Where do you store your

information? How do you store your information? Do you store it in DEC format? Do you

store it in Sun format? Do you store it in PC format? Which one do you think you ought to do?

With Bypass, it doesn't matter. Store it in one of the three, and you will be able to access

one of the three at any time in the future.

DR. FREESE: Other sample applications. Some of the systems are Goddard; I'm aware

of at least two of them. One is people who are doing the analysis on the VOYAGER I and

VOYAGER II data; and actually, I was surprised, but very pleased, to find out that VOYAGER I

and VOYAGER II actually are still sending us data. And it is under constant analysis.

The MAGELLAN program also uses various opUcal and storage devices. The space

shuttle dumps its imagery to Jukeboxes down in Huntsville.

(Change of slide)

NOAA has been using the optical storage systems for their weather satellite and weather

image analysis, as does the Navy for their weather forecasting.

Woods Hole and Oregon State are a couple of examples where they are doing more

photographic mapping, although in this particular case it is of the ocean. And the

Marshall Space Flight Center, along with a few other people, are now really getting interested

in the data distribuUon application, where you can take the dlsk--be it on DEC, Sun, or PC

format--and distribute it across the country or across the world to anybody else on one of those

three particular platforms.

And then, they can do their own analysis on the data and communicate that to the rest

of the world.

These are a few of the classic applications associated with earth resources.

(Change of slide)

DR. FREESE: Other applications include anything to do with images whatsoever--

scanned documents or images, CAD/CAM documents or images. If you have ever had a CAT

scan or an MRI scan, they are used to store those particular images.

DR- FREESE: We already talked about satellites and geologic data analysis.

(Change of slide)

DR. FREESE: Data logging and analysis is sort of interesting. Here is an application

where people used to use tapes, but they found that the tapes weren't archival. You couldn't keep

your tapes around for a long time; the tapes had binders on them, chemicals and glues. The

tapes stick after a while. You see that in your NASA tapes from the 1960s where, when you

unreel the tape, particles fall apart; and the thing pulls apart.

Now, the pharmaceutical industry is converting over to erasable optical disks Just to

solve this problem mandated now by the FDA, where they have got to store all their data; and

they must keep it on-line, and they must keep it for seven years. And they have to keep their

original data.

That's an application where they decided, gee, archival llfe is the number one issue here:

and so, therefore, we are going to store these things on standard optical disks.

1-58
The Bypass TM Solution

* Developed for Rewritable Optical Disks

Works with Many Technologies

Copies Information To/From Foreign Disk Types and

Formats

Uses Simple Commands

Reads/Writes Cartridges From Any Supported System

Easy to Add Other Hosts Quickly

Advantages of the Bypass Solution

* Allows Access to Data in Native File System Format

* All File System Commands Work Normally

* Requires No Modification to Native File Systems or

Applications

* No Need to Intercept Requests and Translate

1-59
Bypass

Device Independent

VMS

SunOS

DOS

MacOS (future)

* Converts DOS 3.x to 4.0

Bv-oass A_Dlications

Share Data Between Field and Corporate Offices

Data Distribution

Move and Release Source Code and Programs

Distribute Disks with Different Formats

1-60
Archiving Applications

Key Issues:

- Ability to Retrieve & Store Data in Future

- Systems Must Be Supported/Serviced

Media Life > 10 Years

Archiving Applications: The Inspire Solution

s

Open System Architecture

Adheres to All ISO/ANSI International Standards

Adheres to all Native File Format Standards

Media Life > 10 Years

1-61
Sample Applications

* On-line Data Storage

* Back-up Data Storage

* Archival Data Storage

Sample Applic_a_tions

CAD/CAM

Image Processing

Medical Imaging

Scanned Document Storage

1-62
Sample Applications

Computer Integrated Manufacturing (CIM)

Geologic Data Analysis

Satellite Image Analysis

Samvle Avvlications

Software Distribution

Data Distribution

Data Logging/Analysis

1-63
Sample Applications

Government/Security

Desktop Publishing

Software Development

Future Directions - Now to '94

3.5" Media Standard Completed

Products Announced

~ 150 MBytes/Cartridge

5.25" Disk: Two to Four x Present Capacity

(1-4 GBytes/Disk) (Backward Comparable) (Standardized)

2 to 5x Increase in Transfer Rates

(20 to 50 Mbits/sec)

15-25 msec Average Access

Half-Height Drives
I should mention the issue of erasability since it was brought up by the prior speaker;

but that's what this industry uses today. They use tapes; tapes are rewritable. Tapes are

erasable; tapes are correctable.

Only microfilm and microfiche is considered not to be correctable.

So, for one to switch from tapes to optical disk was no issue whatsoever.

DR. FREESE: There are a tremendous number of systems in Washington, D.C. all

associated with Government applications and all associated with the removability aspect of

these cartridges. You can keep them on-line in your computer ffyou want; but when you are

done with that data, you can pull it out and stick it on the shell. You can keep your system right

there. If you wanted to send it to somebody, you could.

DR. FREESE: I would llke to take the last few minutes and talk a little about future

directions. I think it's important to realize that all technologies are advancing.

I remember at the beginning of the 1980s hearing somebody stand up at an optical disk

conference and say: This stuff is Just going to wipe out the hard drive industry. And I remember

thinking: Well, I'm not too sure about that. I_e seen Just the opposite.

I_e seen magnetic disk people stand up and say: You know, tape is going to wipe out the

optical disk industry, or whatever. They are all different solutions. They all have different

advantages. And it's a mistake to assume that the technologies aren't advancing; they are.

Five years ago, a lot of people rang the death knell for tapes, saying tapes Just can't go

much further. Yet at the same time, in our own laboratories, we were storing tapes in a helical

scan format with densities a factor of 10, a factor of 20--higher than what anybody was talking

about then.

So, we have to be very, very careful about industries that aren't advancing. I think it's a

good assumption to assume that they all will advance.

What I would like to talk about here is advancements that you will see, I think, in the

optical recording industry between now and the immediate future in a commercial sense.

I won't talk technology because technology isn't a solution to your problem.

Between now and 1994--in fact, the very first thing that is happening this year is your

3.5 inch formats are available; and in the coming years, what you will see is all your PCs that

are coming out of Japan will have a 3.5 inch optical drive or optical drive option associated

with them.

On the 5.25 inch, the issue isn't technology. I can think back to 1983 when, in the

laboratories, we took a standard 650 megabyte optical disk and stored 4 gigabytes on that disk,

Just using the same system that we had back then. The issues are not technology driven in the

optical world; they are standards driven.

It took us eight years to get a standard in erasable optical recording. It then took

another four years to get a standard in the 3.5 inch form factor; and now, the standards

committees are turning their attention right back again to the 5.25 inch.

The 5.25 inch will evolve then, and discussions right now are anywhere between two

and four times the present capacity per disk. So, somewhere between 1 and 4 gigabytes per disk

on the second generation erasable optical 5.25.

1-65
Thekeypart of the standardsis that it bebackwardcompatiblewith your existing

disks. Andthe goodnews,at leastfrom our perspectiveandprobablyfrom this audience's

perspective,is that everybodythat weknow of talking in the standardsbodiesis makingthe

standardbackwardcompatible.

So,whateverdisksyou havegottodaywill beableto beplayedonthe secondgeneration

systemscomingup.

Whenthis occursis a standardizationissue;it is not a technologyissue. Thetechnology

to dothis is gettingto beaboutsevenyearsold. That'sgoodbecauseit makesit good,hard,and

stable. But this is anissueof standards.

In my own personalopinion, that standardizationwill take about two moreyears

becauseit tendsto bea little bit political.

Performancewill increasein terms of transferrates,averageaccesstimes, andgetting

into 1/2 heighttypesof form factors.

(Changeof slide)

DR FREESE:Thereis a lot of talk aboutblue/green laserdiodesand taking the existing

technologyandchangingthe head,changingthe colorsof thehead,andgettinga 4X increasein

capacity. And all that's basicallytrue.

Thekey issuerelaUveto the greenlaserdiodes,which win then giveyousomewhere

around6 gigabytesona 5.25inch disk removableis commerciality.Therearesuchdiodes,I

understand;in fact, lWeunderstoodthat theyhavebeenaroundfor quite a while,but they are

not reliableyet. Theyarenot commerciallyavailableyet.

But betweennow andtheyear2000,thosethingswill becomeavallable;and whenthey

do,you'll seethe samedisks--thesameopticaldisks--takeabout a4X leapin their capacity.

Some interesting work which has not progressed in the commercial world is multiple

beams. All of our technologies today use a single beam to read, write, and erase. But in 1983,

1984, and 1985, we also sponsored work at RCA, where they took 18 beams and recorded all

those beams in parallel simultaneously. Well, the media will do that; the technology will do

that, as soon as laser diode arrays are available in that type of size. Then, you will see another

quantum leap in the data rates.

Finally, between now and the year 2000, there is a great deal of work going on in

lightweight heads--very, very compact heads, heads that look about the same size as a

computer chip or as magnetic heads today.

So, you can expect between now and the year 2000 to see access times close the gap in the

mechanical sense between today and whatever exists for hard drives. Now, hard drives will be

moving; hard drives today are getting into the single digits of milliseconds, but so are these

heads. There is no reason that they shouldn't.

(Change of slide)

DR. FREESE: So, summarizing, and in conclusion, the erasable optical recording

industry is Just starting. It is a new industry. We have found it so far to be a brand new tool for

the work station user. It doesn't eliminate or supplant tapes; it doesn't eliminate or supplant

hard drives or floppy disk drives.

What it is, is an additional option in the hierarchy of storage solutions for the user.

There is a tremendous growth path for this particular technology; and usually, the main

1-66
Future Directions - Before Year 2000

Green Laser Diodes

Capacity up to 5-6 GBytes/5.25" Disk

Multiple Beam Laser Diodes

Data Rates 80-160 Mbits/sec

Lightweight Heads (Holographic, Luneberg)

Access Times Similar to Hard Drive

Summary.

Erasable Optical Industry Just Starting

New Tool for Workstation; Networked User

Significant Growth Path

Wide Variety of Applications, Many New

1-67
reasonwhy companieshavegotteninvolvedis for this particular growth path. And a lot of the

applicationswhich weareseeingfor opticalstoragetodayarereallyJust starting.

PeoplearerediscoveringtheJoysof removability,thejoys of standardizationand open

systemsarchitecture,and theJoysofrandomaccesstapedevices.

So,thank youverymuch for beinga real patient audience.If you haveanyquestions,

dowehaveafewminutesfor questions?

1-6g
MAGNETIC DISK

John C. Mallinson

MALLINSON MAGNETICS, INC.

7618 Reposada Drive

Carlsbad, CA 92009

N93-13134

Magnetic disk recording was invented in 1953 and has under gone intensive

development ever since. As a result of this 38 years of development, the cost per byte and the

areal density have halved and doubled respectively every 2-2 1/2 years. Today, the cost per byte

is lower than 10 -6 dollars per byte and areal densities exceed I00 106 bits per square inch.

In this talk, the recent achievements in magnetic disk recording will first be surveyed

briefly. Then the principal areas of current technical development will be outlined. Finally,

some comments will be made about the future of magnetic disk recording.

PRESENT ACHIEVEMENTS

High end disk drives today operate at areal densities of between 50 and I00 106 bits per

square inch, with, typically, 2500 tracks per inch and 30,000 flux reversals per inch. When

"run length limited" coding is used, the effective linear bit density is 40,000 bits per inch. Areal

densities tend to be higher the smaller the diameter of the disk.

Data rates run as high as 6 Megabytes per second (48 Megabits per second} per single

head-disk channel. Parallel access disk systems, with as many as 10 heads in parallel have

been manufactured which provide the full CTIR 4:2:2 component digital video output rate (216

Megabits per second).

Since as many as 6 disks can be fitted in the standard 5 1/4" full height form factor

package, 5 1/4" drive data capacities exceeding 2 Gigabytes are now available from several

manufacturers.

In summary, it may be said that the magnetic disk products being manufactured today

offer access times, data rates and drive bit capacities considerably in excess of those offered by

optical disk drives. Areal density is the only parameter which currently falls below that of

optical disks, by a factor of 3-4.

AREA_ OF TECHNI_L DEVELOPMENT

The overwhelming success of magnetic disk products over the last three or four decades

has led to the establishment of a $50 billion per year world wide business in disk drives. This

enormous business support research and development into every conceivable aspect of disk

recording technology in order to permit continuing increases in performance. Only the major

areas of such research and development can be discussed below.

IMPROVED RECORDING MEDIA

Virtually all modern disk drives now use thin film metallic media with coercivities

close to 1000 Oe. It may be expected that coercivities exceeding 2000 Oe will be used in the next

few years. Higher coercivities lead to both sharper output pulses of greater amplitude and also

to improved signal-to-noise ratios.

IMPROVED WRITING HEADS

As the medium coercivity increase, it is necessary to increase the saturation induction

of the writing head pole tip materials. Presently, Alfesfl and Permalloy with maximum

1-69
inductionsof 10-12,000Gareused. MaterialssuchasCo-RuandFe-Nwith maximum

inductionof 16,000and 19,000Gmaybeexpectedto beintroduced.

NARROWER TRACKwILrrkiS

It has been realized for two decades that, when seeking higher areal densities, it is better

to use narrower trackwidths than higher linear densities. Operation with trackwidths

substantially narrower than normal (10lxm) leads to a number of very fundamental questions

concerning the operation of the track following servo system. In particular, the outstanding

question is %vhat is the source of the tracking error signal?". In magnetic disks today the

source is a previously written magnetic disk servo track and it is only possible to operate the

tracking servo when reading but not when writing. In optical disks, which operate at 5-6 times

the track density, the source is always some physical feature (pits, grooves, bumps, etc.) and the

tracking servo system is then operable during both reading and wr/tbnq. This leads to another

question: '_rill magnetic disks eventually use optical tracking servo systems?".

IMPROVED READING _S

As trackwidths decrease, it becomes increasingly difficult to keep the channel signalto-noise ratio media-noise limited because the output voltage of an inductive head falls

proportionally with the trackwidth. It is anticipated that the next generation of high end disk

drives will use magneto-resistlve (M-R) reading heads where the magnetic fields from the

medium changes the electrical resistance of a thin film M-R element. Considerably higher

output voltages are available with M-R heads and they are independent of head-medium

relative velocity.

IN-CONTACT OPERATION

Today's disk drives operate with a deliberate head-to-disk spacing of, typically, 6-8

microinches (0.15_m). It is known that both the writing and reading processes on magnetic

disks improve when the spacing is reduced. All disks today are overcoated (Ag-Sn, ArO 2

amorphous C, ZiO2, etc.) in order to control friction and wear and it seems very likely that,

together with redesigned heads of significantly lower mass, continuous operation in contact

may become possible. This is particularly true at low head-to-disk relative velocities.

SMALLER DISK DIAMETER_

An interesting sequence of design changes becomes possible following a reduction in

the head-to-disk spacing. First, a higher linear density may be written. Second, because the

data rate has now become too high, the disk diameter or spindle RPM must be reduced. Third,

at the reduced head-to-disk velocity, it now becomes possible to reduce the head-to-disk

spacing even further because any mechanical impact now transfers less energy. Fourth, if a

smaller disk diameter has been chosen, the mechanical tolerances (flatness, areal runout, etc.)

are reduced which again permits the head-to-dlsk spacing to be reduced even further. This

sequence has led the drive industry from 5 I/4" to 3 1/2" to 2 1/2" to 1 1/2" diameters with

increasing areal density. Still smaller diameters and higher areal densities are anticipated.

As an example of the levels of performance attainable when many of these

developments are combined, consider the 1989 IBM _ (I 100 Megabit) per square inch

technology demonstration:

Medium coercivity - Cobalt-Platinum - 1700 Oe

Write Head-thin fflm-trackwidth 4_n

Read Head - magneto-resistive - trackwidth 2-3_m

Head-to-dlsk spacing - about 1 microinch

Linear density - about 160,000 bpi

Track density - about 7,000 tpi

1-70
With this demonstration,IBM showedthat magneticdisk recordinghas the potentialto

exceedtoday'sopticaldisk arealdensitiesby abouta factorof 2.

TheIBM 1989demonstrationproved1.I Gigabitper squareinch feasibility. Today's

researchpapers(see,for exampleIntermag'91 paper MA-01) discuss demonstrations of 2

Gigabit per square inch (at 17,000 tpi and 120,000 frpi). It seems to be abundantly clear that the

magnetic disk recorders could range from the 50-100 Megabit per square inch of today's

manufactured hardware to future products with areal densities perhaps as high as 16 times

greater.

It used to be said that the great advantage of optical (versus magnetic) recording was that

it was not necessary to fabricate anything with dimensions comparable to the wavelength of

light in order to achieve very high areal densities because the lens could focus the light down to

Lord Rayleigh's' diffraction limit.

Nowadays, it seems that a very fundamental change in philosophy has occurred.

Indeed, it is frequently stated that the real advantage of magnetic versus optical recording lies

in the fact that the only effective limits operating today concern Just how small can certain

features and objects be made and that their dimensions are not limited bu mere physical

diffraction of lightf For example, the gap-length in mass-produced 8 mm VCR heads is I0

microinches, which is but one third the wavelength of red light.

The steady increase in areal density, by a factor of 2 every 2-2 1/2 years, has been

mentioned already. By this criterion alone, it appears then that magnetic disk recording

technology can sustain another 20 years of growth ( a factor of 16 = 24; 4 x 2.5 = 10 years) on the

basis of demonstrables which exist in the laboratories today.

To move from scientific extrapolation to the realm of technical speculation, it seems to

be very likely that I Gigabit (109) per square inch areal densities will appear in disk (and video

tape) drives in considerably less than 20 years. Indeed some industry observers have opined

that 5 1/4" full height drives with I00 Giga-byte capacity will appear before the year 2000: this

represents a doubling of the historic rate of increase. Given the magnitude of the research and

development activities in magnetic disk recording being undertaken worldwide, even such

surprising estimates do not appear, to this writer, to be unduly optimisticl

1-71
AREAL DENSITY

= TRACK DENSITY x BIT DENSITY

(TPI) (BPI)

VOLUME DENSITY

= AREAL DENSITY x !

THICKNESS

TYPICAL AREAL DENSITIES,

CAPACITIES AND COSTS TODAY

HI-END (LARGE)

HI-END (SMALL)

HI-END (SMALL)

AREAL CAPACITY COST

60 106 10 109 $100K

100 106 2 109 $2000

20 10s 0.1 109 $400

NOTE: 10-4 CENTS/BYTE

10-5 CENTS/BIT

AREAL IS IN BITS/SQUARE INCH

CAPACITY IS IN BYTES

1-72
EFFECT OF RAISING He

+M

t

I

m

r_- -Ao_.

MAGNETIZATION

-M

-,.4

DISTANCE

0,,, (_ _" Hc

DATE

1980

1986

1989

Now

Future

Hc (OE)

3O0

600

9O0

1200-1400

2800 Reported in Literature

1-73
/ RECORDING MEDIUM WITH HC

, \

Ho = 2.5 HC

Ho s 0.6 BS

(TO WRITE PROPERLY)

(TO AVOID POLE TIP SATURATION)

WITH FERR#TE POLE TIPS BS = 5000 G

0.6 BS = 3000 G

.'. MAX HC= 1200 OE

METAL-IN-GAP HEADS

GAP

1-74
MAGNETO-RESISTIVE HEADS

M

SINGLE DOMAIN THIN FILM

v

RESISTANCE VARIES AS (COSINE G) 2

V (MRH) -- 20,000 V (INDUCTIVE)

SPEED x NO OF TURNS

SUPPOSE DISK SPEED IS 200 IPS:

V (MRH) -- 20,000 x V (INDUCT) FOR N = 1

= 2,000 N = 10

= 200 N = 100

- 20 N = 1000

MRH ARE THE KEY TO HIGHER TPI's WITH SMALL DIAMETER DISKS.

"IN CONTACT" DISKS

1-75
OPTICAL DISK_;

THE TRACK FOLLOWING ISSUE

ATTAIN 10-15,000 TPI

ALL USE DIFFRACTION OF LIGHT OFF

MECHANICAL FEATURES

MAGNETIC DISKS CURRENTLY ATTAIN 2-3,000 TPI

ALL USE A _ SURFACE

WITH MAGNETIC SERVO TRACKS

IDEALLY, THE SOURCE OF THE TRACK FOLLOWING SERVO SIGNALS SHOULD BE INDEPENDENT OF

THE RECORDED DATA, SO THAT THE TRACK FOLLOWING SERVO CAN OPERATE AT ALL TIMES.

WILL MAGNETIC DISKS ADOPT OPTICAL TRACKING?

A)

B)

c)

D)

E)

OR F)

G)

SMALL DISK EVOLUTION

MAKE DISK SMOOTHER

LOWER FLYING HEIGHT

INCREASE LINEAR DENSITY

REDUCE SPEED

LOWER RPM

SMALLER DISK

SMALL DISK IF FLATTER

.'.LOWER FLYING HEIGHT AGAIN

ACCELS LOWERR AT LOWER RPM

,'.LOWER FLYING HEIGHT AGAIN

REPEAT CYCLE (C)

1-76
Metallic Thin Film Disk

Inductive Thin Film Write Head

Magnetoreslatlve Read Head

50% Roll-Off Density

Linear Bit Density

Data Rate

Error Rate

Signal-to-Noise Ratio

Areal Density

IBM'S 1 GIGABIT/INCH 2 DEMONSTRATION

DECEMBER, 1989

H C = 1800 Oe

= 300A Co-Pt-Cr

W = 4_m

6-7000 TPI

W -- 3_.m

= 110,000 FRPI

= 160,000 BPI

28 Mba

= 10 .8 . 10-9

= 23 dB

= 1.18 109 Bits/inch 2

SIGNAL POWER

........................ : No OF GRAINS/BIT CELL

NOISE POWER

IBM'S DEMO HAD 500 ,_, (2_. INCH) METALLIC GRAINS

THE BIT CELL WAS ABOUT 61_" LONG X 1201_ " WIDE

... No OF GRAINS/BIT CELL = 200

... SNR = 200 OR 10 LOG 10 200 = 23 dB

This demonstrates that the basic laws governing recording hold to Giga-bit densities.

Note that a doubling In areal density costs a halving (-3 dB) In SNR with thin media.

1-77
THE FUTURE

SUPPOSE 2X AREAL DENSITY

EVERY 2 1/2 YEARS HOLDS

DATE AREAL DENSITY

1991 100 106

1994 200 106

1996 400 106

1999 800 106

2002 1600 106

This evolution appears to be reasible on the basis of today's laboratory demonstrations.

A PROFOUND CHANGE IN DESIGN PHILOSOPHY

The advantage of optical recording Is that dimensions comparable to optical

wavelengths do not have to be manufactured.

The advantage of magnetic recording is that the effective limits are governed by

how small can objects be made and this limit far exceeds optical diffration.

1-78
N93-13135

MAGNETIC TAPE

Harriss Robinson

Datatape Incorporated

ABSTRACT

The move to visualization and image processing

in data systems is increasing the demand for

larger and faster mass storage systems. The

technology of choice is magnetic tape. This

paper briefly reviews the technology past,

present, and projected. A case is made for

standards and the value of the standards to

users.

INTRODUCTION

Major changes are occurring in data storage and

processing systems technology. It is hard for

most of us to keep up with what is happening in

our own fields, let alone what is going on in

related disciplines. Even when we can see the

general direction of change, it is difficult to

forecast the timing and implement systems which

bring all elements together at the same time to

provide optimum performance, at a reasonable

cost.

implementation of more and larger mass storage

systems.

A recent issue of Business Week lists IBM as

the number one U.S. Company in terms of

market value. 2 IBM's sales of magnetic storage

products (disks and tape drives) are said to

exceed the sales of their mainframes. Annual

sales of magnetic recording products now exceed

$50 billion and can be expected to grow. a

Computer manufacturers probably sell more

disks than tape drives, but the tape market itself

is very large. A recent Seagate ad says that

"Seagate shipped over seven million disk drives

alone last year (1990). ',4 The reason for

including these impressive statistics here is to

help dispel any perceived notion that magnetic

recording is out of date. Other new

technologies such as optical recording have their

place, but this paper will demonstrate the

advantages of magnetic tape for large mass

storage systems.

One fundamental change affecting all of us is

the emergence of the discipline called

visualization. Visualization requires storage of

very large image files, e.g., megabytes per

image, versus kilobytes per typical alpha

numeric file (1000 to 1). The requirements of

visualization have not only brought about

changes in the design of processors from

character to image processing, but also a

recognition of the need for larger and faster

storage systems.

Another major change affecting all of us is the

improvement in data communications; not just

satellite links, but network buses which handle

high data rates with packet switching protocols

for peer-to-peer and client/server

communication. Using fiber optics, data of

various bandwidths can be digitized, buffered,

and transmitted in packets over long distances. _

Network buses will not on b facilitate more

distributed computing, but also the

For those of us in the magnetic tape industry,

we have difficulty hearing words like

"peripheral" and seeing pyramid shaped icons

with mainframe storage at the top, then solid

state disk, then magnetic disk, then optical disk

and finally magnetic tape (Figure l). After all,

what media stores all of the permanent data for

long periods of time? Well, if we were

processing time card charges, point of sale

transactions, inventory movement, or some

other batch process requiring only short term

back-up, we would view the whole process the

traditional way. But, if we were processing

terabytes of sensor data daily and storing it for

years, we would view things differently. We

would want a storage technology that is very fast

(e.g., HlPPI rates), uses inexpensive media, has

high data integrity, uses time proven technology,

and standard media and storage devices.

Perhaps the stack of storage technology would

be the same, only in our view the central

memory and direct access storage are only little

1-79 J_,ly 1001
bumps on the large tape storage archives (see

Figure 2).

A

_OLID STAT_

DISK '_,

DISK

PTICAL DISK

GNETIC TAPE '_

Figure 1. Typical ICON Representation of a

Traditional Storage Hierarchy

MAIN MEMORY

,__ AND SSD

Figure 2. Storage Hierarchy for

Large Mass Storage System

Humor aside, a serious attempt will be made to

present magnetic tape storage in the context of

the conference, i.e., Mass Storage Systems for

Space and Earth Science Applications. At first,

the writer was tempted to deal with magnetic

recording technology from the standpoint of

design, but on reflection it was decided to cover

only those issues deemed most important to the

audience. For those who want to delve more

deeply into the design of digital magnetic data

recorders, several sources of technical data are

recommended. They are 1) NASA Reference

Publication 1111, "High Density Digital

Recording," prepared by THIC, September

1985, available from the Superintendent of

Documents; 2) Magnetic Recording Handbook

edited by C. Dennis Mee and Eric D. Daniel

and published by McGraw Hill, 1989; 3)

Magnetic Recording Handbook edited by

Marvin Camras and published by Van Nostrand

Reinhold, 1988; 3) The complete handbook of

Magnetic Recording by Finn Jorgensen and

published by TAB BOOKS INC., 1986

Other valuable sources of data are found in two

IEEE publications: (1) November 1986

proceeding with a special section on Magnetic

Information Storage Technology edited by' Mark

Kryder, Professor of Electrical and Computer

Engineering and Director of the Magnetics

Technology Center of Carnegie Mellon

University of Pittsburgh, Pennsylvania. (2)

June 1990 special issue on Magnetics

incorporating an invited paper by John C.

Mallinson, Fellow IEEE and Director of the

Center for Magnetics Research, University of

California at San Diego. The paper is entitled

"Achievemenls in Rotary Head Magnetic

Recording."

i-8o

.luly 199 I
TECHNICAL PERSPECTIVE

There is a lack of public understanding, and

even a lack of understanding among electrical

engineers, concerning the importance of

magnetic storage technology. Which came first,

computers or magnetic storage? Of course

magnetic storage came first ,making computers

possible.S

Magnetic tape recorders record data differently

than semiconductor memories. Semiconductor

random-access memories and logic devices store

ls and 0s by controlling the state of

semiconductor devices. Power for storage and

readout of the devices is supplied by the

memory power supply or battery back-up.

In digital magnetic recording, bits are stored by

creating magnetic domains in moving magnetic

media. To store strings of encoded ls and 0s

in magnetic tape, the tape must be moved past

a magnetic recording head. Magnetic domains

are created in the thin layer of ferromagnetic

particles in the surface of the tape by the field

of the drive current. Similarly, encoded Is and

0s are read from the tape by sensing tile rate of

change of the magnetic flux. Domains are

created in the tape at discrete intervals whose

lengths are inversely proportional to the

recording data rate and the speed of the media

past the head.

The two most common magnetic recording

techniques are illustrated in Figure 3. In

longitudinal recording, modern machines

typically have 9, 18, 28, 36, 42, or 84 tracks.

Contemporary helical-scan recorders achieve

higher track densities and higher bit densities,

i.e., flux reversals per unit length of track. A

rotary scan technology similar to helical scan is

transverse scanning wherein the tracks are

orthogonal to the direction of tape travel. This

method is mentioned briefly in the next section.

Because the magnetic recording process seems

complicated when its compared to

semiconductor memory, why is it used? The

answer is very low cost and very high storage

density at high data rates. As an example, the

ANSI ID-1 Helical Scan Recorder stores data

on large tape cassettes at a media cost of less

than two tenths of a cent per megabyte and at a

density of 625 megabytes per cubic inch with

data rates up to 50 MBytes per second.

LONGITUDINAL

HELICAL

Figure 3. Magnetic Tape

Recording Techniques

The energy identifying every bit of storage is

stored as a domain of spinning electrons in the

particulate media. These domains remain

indefinitely unless demagnetized by an external

field greater than the coercivity of the tape.

HISTORICAL PERSPECTIVE

Widespread use of magnetic tape recording

began in the late 1940's. Since then many

recorder configurations have evolved by many

manufacturers and a great many still exist with

refinements. In the beginning, they were all

analog machines recording complex wave forms

for instrumentation, audio, and video

applications. In 1956, Ampex invented

transverse scan rotary recording and launched a

product successfully for broadcast video

recording. 6 RCA followed with its transverse

scan products in 1958. These machines were

called "quadrature" machines because the heads

scan across the tape at a quadrature angle with

respect to the direction of tape (90°).

The most significant aspect of this early rotary

recording technology is that it permitted very

high head to tape speeds (over 3000 inches per

second) and high track density, hence high

video bandwidths and large storage capacity.

Magnetic tape was selected in the early 1950's

to transfer data at high speeds to and from

computers. 7 These were 7-track and later

9-track longitudinal recording machines, some of

which are still in service. In tile 1970's and

1-81 .h,ly _991
1980's, 1/2" tape cartridges and 1/4" tape

cassettes were introduced for longitudinal data

recording. DATATAPE introduced its System

600, 84 channel longitudinal digital data

recorder, in 1980. The System 600 machines

are capable of selectable record and reproduce

rates from 6.25 to 56 megabytes per second.

The earliest reference found in the literature

regarding computer tape drives using rotary

heads to achieve high information densities on

tape (Damron, et al, 1968) is on p. 6 of

chapter 4, referenced above. 7 Starting in the

early 1980's, DATATAPE began producing a

number of high data rate, high storage capacity

helical scan recorders for DOD. Three of these

machines are pictured in Figure 4. All three

are still being manufactured. Please note that

the RDCR-331 is a mass storage system with

automated cassette handling.

Two other versions of the RDCR have been

manufactured in quantity. The first uses an

NEC jukebox with 3M tape cassettes in the

shape of D-1 tape cassettes, but with 1" wide

tape instead of 19mm (3/4") tape. The second

version produced cooperatively for Masstor

Corporation is being sold in commercial mass

storage systems.

CONTEMPORARY DIGITAL DATA

RECORDERS

By all odds, the high volume digital data

recorders of recent note have been the

3480/3490, 1/2" machines manufactured by

IBM, Storage Technology and others. These

longitudinal machines operate with a Federal

Information Processing Standard -60 (FIPS-60)

Interface. Their data rate, 3--1 megabytes per

second, and their modest cartridge storage

capacity (200 plus megabytes) have been

adequate for contemporary mainframe storage.

These recorders, manufactured in the

thousands, if not hundreds of thousancls, sell for

reasonable prices, in the range of $10,000 to

$20,000 each. They are also available in large

automated storage silos, e.g., Storage

Technology Corporation's ACL-4000 which

stores over 1 terabyte.

Also of particular note has been the success of

8mm helical scan tape recorders manufactured

1-82

by Exabyte Corporation. Sold by many system

integrators and re-sellers for small computer disk

back-up applications, these machines are based

on the use of a Sony 8mm video tape drive with

Exabyte developed digital data electronics. Sold

with Small Computer System Interface (SCSI),

these machines operate at a burst data rate of

1,5 megabytes per second and store 2.3

gigabytes. A higher density version of this

machine is available with 1638 tracks per inch

(tpi) versus 819 tracks per inch and stores

5 gigabytes . Both Exabyte machines use metal

particle tape. Other value-added suppliers of

Exabyte Recorders include Megatape and

Summus Corporation. Summus also sells the

Exabyte machines with automated carousels.

Both of these suppliers offer standard peripheral

interfaces.

Some additional contemporary machines deserve

mention. The first is the Metrum VLDS 1/2"

Helical Scan tape cartridge machine based on a

VHS product. In a dual channel version it is

capable of a 3 megabytes per second data rate

and in a single channel version 1.5 megabytes

per second. In a read-after-write version, the

dual channel machine is reported to be capable

of achieving a corrected bit error rate (CBER)

of 1 error in 1012 bits with a transfer rate of 1

megabytes per second. This machine is being

produced in volume. It is available with an

automatic cartridge changer which holds up to

600 cartridges. The machine is available with

TTL, SCSI-1, VME, and VAX DRB-32

interfaces. The machines use cobalt doped

gamma ferric oxide tape on standard 5.2

gigabyte cartridges, with 10 gigabyte cartridges

available. The recording format on tape is

proprietary to Metrum.

A higher performance transverse scan tape

cartridge machine is the AMPEX DCRSi which

operates at 13.4 megabytes per second and

stores 47.5 gigabytes per cartridge on cobalt

clopecl gamma ferric oxide 1" wide tape. The

machine has a 96 megabyte buffer which allows

read or write at any rate up to 13.4 megabytes

per second. The machine is available with

either a serial or 8 bit parallel TTL interface

and an RS-232 or RS-422 control and status

interface. Several hundred machines are in

service. The tape format is Ampex proprietary.

July lg91
DDR-100

(2 Terabits per reel)

250 GBytes/Reel

44 KBPI

Track Pitch 1.6 mils

MDR

(5 Terabits per reel

625 GBytes/Reel

44 KBIPI

Track Pitch 1.2 mils

:i:i:i:i:i:i ":':':

.:.:.:.:.:+

ii

RDCR-331

(7.6 Terabits per JB)

950 GBytes/Jukebox

Track Pitch 1.2 mils

Figure 4. Recent DATATAPE Helical Scan Digital Data Recorders

1-83 .)uly 1991
Not included in this paper are detailed statistics

on a series of 4mm helical scan tape cartridge

machines which are based on DAT (digital

audio tape) consumer products. Generally

speaking, they have transfer rates of 0.19

megabytes per second, read-after-write, storage

capacity of 1.25 gigabytes per cartridge, CBER <

1 error in 10 is bits, and SCSI-I and PERTEC

interfaces. The machines use 1400 Oersted

metal particle tape available from a number of

manufacturers. Systems are said to be available

from Archive, Caliper, Gigatape, Gigatrend,

Hewlett Packard, Hitachi, Sony, Wangtek,

Wang Dat and others. There are two proposed

standards. The most interesting aspect of these

machines is their high data density: 61000 bpi

with 535 micro-inch track spacing (1869 tpi).

Another helical scan storage system of note is

the Masstor M-960 Cart Machine which

operates with the Masstor M-1000 storage

Library. These machines are 2 terabyte libraries

with FIPS-60 Interfaces and are operated

on-line for large enterprises.

HIGH PERFORMANCE 19MM HELICAL

SCAN DIGITAL DATA RECORDERS

Several years ago, an industry and government

working group was formed to generate a

standard for a new 19ram digital data recorder

(ID-1). The ID-1 standard would permit D-I

Digital Broadcast Tape Drives to be used with

changes to the tape footprint and with new

digital data electronics. The data electronics

would incorporate Reed Solomon RS 4/5 Error

Correction Circuitry and other desirable

attributes, e.g., Scan Block ID and longitudinal

search and annotation tracks. The machines

would be available from several manufacturers

and tape cassettes recorded on one

manufacturer's machine could be reproduced on

another's. This would avoid or at least mitigate

the problem anticipated by some "that eternal

copying from one format to the next will be

necessary" .8 (If, in fact, some images may be

required to be stored for very long periods,

photographic film may be the media of choice,

e.g., witness civil war photographs.)

The ID-1 Working Group included

representatives from the following organizations

(see Table 1) :

Ampex

Bow Industries

Datatape Incorporated

Fairchild Weston (now Loral)

Honeywell (now Metrum)

Odetics

Memorex

RCA (now GE)

Sandia

Schlumberger

Sony

U.S. Government (NASA and DOD)

Table 1. ID-1 Standard Working Group

The decTicated effort of many individuals over

an ex nded period of time resulted in the

appro al of the Standard by the American

National Standards Institute, Inc., on December

7, 1989. It is identified as ANSI X3.175-1990,

American National Standard for Information

Systems - 19mm type ID-1 Recorded

Instrumentation - Digital Cassette Tape Format;

Secretariat, Computer and Business Equipment

Manufacturers Association.

In the last two years, new ID-1 products have

been announced by most of the companies

represented on the working group. They

include GE, Metrum, Loral, Sony, and

Datatape. The cost to bring such new products

to market is estimated to be in the millions of

dollars, if not tens of millions of dollars.

At first the writer had planned to tabulate the

performance values for the products offered, but

on reflection, it was recognized that a mistake

might be harmful. At any rate, the data

recorded by one manufacturer can be

reproduced by any other, right? Yes, we expect

it can, but the data might not be useable, if the

data has been compressed or encrypted, and the

reproducer does not have the equivalent

decompression or decryption equipment. The

same applies to the use of external buffers

and/or enhanced interleaving/error correction

techniques. Because of this, an ANSI Working

Group has been formed to draft a standard for

the use of ID-I machines modified to meet

computer peripheral recorder requirements and

meetings are in process.

1-84 .July 1991
It should be noted that the ANSI ID-1 standard

does not prescribe data rate for recording or

reproduction. Because of speed scaling, the

foot print on tape is the same regardless of data

rate, within limits. Accordingly, some

manufacturers are offering machines with lower

maximum data rates.

In the meantime, Datatape has announced the

availability of a Variable Rate Buffer which can

be used with the Datatape DCTR-LP series

machines to provide read-after-write and rewrite

capability with rates up to 50 megabytes per

second using standard computer control and

status interfaces with ECL data channels. The

DCTR-LP machines can also be used with a

CHI Systems interface to operate over a HIPPI

channel with IPI-3 protocol. CHI Systems has

also announced the availability of its IPI-3 and

VME bus interfaces with other manufacturer's

ID-1 products. The block diagram of CHI

Systems HIPPI-DCTR-LP interface is shown in

Figure 5.

HIPPI-DCTR-LP INTERFACE

_o

DCTR-LP

IEEE488

control

HIPPI DEVICE

(IBM, SWITCH,

etc,,, )

IEEE488

control

Figure 5. Chi Systems DCTR-LP

ID-1 Interface

The Datatape Variable Rate Buffer has up to

448 megabytes of dynamic ram in order to

buffer recorder data at rates up to 50 megabytes

per second and to provide read-after-write and

rewrite.

Some of the features of the Datatape ID-I

machine are illustrated in the following

paragraphs as generally representative of all

ANSI standard ID-l machines. It will be noted

that some of the illustrations include

characteristics representative of MIL-STD-2179,

e.g., zero azimuth tracks which are available

from Datatape and others, but, generally

speaking, this presentation is intended to

highlight ID-1 azimuth recording tracks in which

alternate scans are recorded with the azimuth

shifted fifteen degrees; first in one direction,

then the other. While azimuth recording may

cause a slight reduction in SNR when exactly on

track, the advantage achieved in raising tracking

tolerances is considered advantageous for all

concerned and is in keeping with the ANSI

X3. 175 standard.

A comparison of ferro fluid pictures of 0

degrees azimuth and +/- 15 degrees azimuth

recording is shown in Figure 6.

I

i

MIL-STD-2179 FORMAT

0 ° AZIMUTH RECORDING

ANSI ID-1 FORMAT

: f'i!

i.;.:: , :_ii:i_'b:': :i:.: L:i.!:.:':..,"i ::::::::::::::::::::::::::::::::::::: !

: : :_:_: _ :.:i_i!i:ii:_;ii2!i;?i_i!::::i::i_i:'.'i._!;ili!f:: ; i:!:'.:':iiiii::il:i

::._, . ::.:, ..: :.:": ,4::-: .::::.. ::::_, )17. :_ -:================= ====:2-<

' :!-:% :_ "::::: i :i ;,::::;:!;:'_:!-::: ::: :.i:::!;;:i::_: :!,,)?:':

.:.i i ?" :!;'::._'; )::!e :: : ..-;??_?::_ ?_i; .',;? _.')::_.::_::: : i::?,!:_ ;:;

+__15° AZIMUTH RECORDING

Figure 6. Azimuth Recording

1-85 July 1991
Performanceparametersof MIL-STD-2179/

ANSIID-I DataRecordersareshownin Figure

7.

To providethereaderwithanappreciationfor

thehead-to-tapeinterfacefor anANSIID-1

recorder,thetapeformatandtheDatatape

DCTR-LPseriesscannerisshownin Figure8.

Thethingto noteisthatat 10,380RPMthe

headis literallymovingat over90milesper

houralonga track_hichis narrowerthanthe

diameterof anaveragehumanhair.

DRUMDIAMETER

ACTIVEWRAPANGLE

AZIMUTH

TRACKPITCH

SCANNERRATE

NUMBEROFHEADS

TAPEVELOCITY

HEAD-TO-TAPESPEED

USERDATARATE

TAPEDATARATE

INSTANTANEOUS ttEAD

DATARATE

LINEARDENSITY

SPEED/RATERANGE

_HANNELCODE

BERWITttERROR

CORRECTION

SNIPTED-I 400Mbilts 31}0 ,'klbitls 200 Mbit/s

DTTR RECORD E P. R ECO R I) I:.R P, ECO RD ER

2.95 IN 2.95 IN 2.95 IN 2.95 IN

257 ° 256 ° 257 ° 258 °

0 ° +15 ° OR 0° +15 ° OR 0° +15 ° OR 0 °

1.8 MIL (45 ,u.m) 1,8 MIL (45 j.tm) 1.8 MIL (45 lain) 1.8 MII, (45 btm)

149,0 R/S 173.1 R/S 173.1 R/S 173.1 R/S

4 8 6 4

11.3 IN/S 26.1 IN/S 19.5 IN/S 13 IN/S

1401 IN/S 1632 IN/S 1625 IN/S 1619 IN/S

179 Mbit/s 400 Mbit/s 300 Mbil/s 200 M'bil/_

225.1 MbiX/s 533 Mbilts 400 Mbil/s 265 Mbil/s

78.7 Mbil/s 93.9 Mbil/s 93.5 Mbil/s 92.6 Mbil/s

56 KBil/IN 57 Kbil/lN 57 Kbil/lN 57 Kbi_qN

SINGLE SPEED 8:1 8:1 8:1

RANDOMIZED 8/9 DC FREE CODE FOR VARIABLE SPEED.

ANSI- ID-I ALSO INCLUDES RANDOMIZING

lXl0-_° W/ECC IXl0-m W/ECC IXl0-_° W/ECC

(R:S) (R/S) (R/S)

1Xl0 -6W/ECC

Figure 7. M1L-STD-2179/ANSI ID-1 Data Recorders

--- .. , }

........... iiiii!i:!

DCTR-LP

SCANNER

75 mm (3.0")

10,380 RPM

DIRECTION OF TAPE TR_.VEL

ACFERENCE EOGE-'/ O? 10 lg

(DIMENc_iON5 IN MI[.JJMLTKR<_)

Figure 8. Tape Format and DCTR-LP Scanner

146

luly 109 I
Perhaps more remarkable is the nature of the

head itself shown in Figure 9. The head gap

length is only 0.3 micro-meters. This is one

half the wavelength of visible light (average

0.6 gm). Therefore, since the gap length is

shorter than the wavelength of light, the

headgap cannot be viewed directly with an

optical microscope. It is viewed only by a

scanning electron microscope (SEM). Is it any

wonder then that optical 3.5" and 5.25" disks

have linear recording densities of only 31.8

kilobits per inch (kbpi) compared to 57 kbpi for

the ID-1 machine, 75 kbpi for the 8mm Helical

Scan Machine, and 38 kbpi for the 3480. 9 The

point to be made in comparing the linear

density of the magnetic recorders to the optical

disks is not to say that the magnetic recorder is

superior, per se. They are in the same general

ball park with regard to linear track density, but

tape has other obvious advantages like data rate,

capacity, and cost per megabyte.

0.053 mm

/

I

TRACK WIDTH

0.045 mm

GAP LENGTH 0.3ta m

(INVISIBLE)

10011 f

....., _,f 15°

Figure 9. ANSI ID-1 Record Head used on

DCTR-LP Series Recorders

The rotary headwheel for tile DCTR-LP series

ID-I machines is shown in Figure 10. There

are 16 sections on the rotary transformer

making it possible to use up to 8 record heads

and 8 reproduce heads to achieve a 50

megabytes per second data rate. It should be

noted that to go from 25 megabytes per second

to 50 megabytes per second it is not necessary

to push the record and reproduce circuitry for

higher frequency performance; it is merely

necessary to use more circuits, i.e., head

drivers, pre-amps, equalizers, etc.

The tape cassettes used in the ANSI ID-1

machines are shown in Figure 11. Please note

that 13 gm tape is listed as well as 16 gm tape

even through, at this time, only 16 gm thick

tape (0.4") tape is being used in ID-1

machines.

The Datatape ID-1 Laboratory Machine, the

DCTR-LP series, is illustrated in Figure 12.

These machines are designed for 19-inch rack

mounting either as one unit 30 inches deep or

as two units side by side (see Figure 12). This

laboratory version of the Datatape DCTR uses a

tape drive developed by BTS in Germany

together with the data electronics unit developed

at Datatape in Pasadena.

An airborne version of the ID-I machine is

shown in Figure 13. It has been designed to

meet MIL-E-5400 environments. This machine

is manufactured in Pasadena, except for the

scanner which is made in the Datatape, Santa

Clara, California Facility.

The ID-1 machines designed for digital dala

collection and for mass storage with data

buffering, represent a broad industry push to

satisfy a generation of digital data storage

requirements. A conservative approach has

been taken in advancing the ID-I designs as

noted below:

t. Track Spacing: 0.045mm (0.0018")

The tracks are contiguous on tape (no

lost space) and the tracks are generous,

both in width and bit density. This is

important when using the machine for

recording or reproducing short bursts

where longer time intervals are not

available, e.g., to lock-up head tracking

servos.

2. The 850 Oersted tape also represents a

conservative design approach. It uses

cobalt treated gamma ferric oxide tape

which has been proved in over 20 years

of service.

1-87 ,luly 1091
. High data rates and storage capacities

are achievable with current designs, i.e.,

50 megabytes per second vs 15

megabytes per second for the D-2 based

digital data recorder discussed briefly

below.

. With multiple suppliers of equipment

designed to standards, it is highly

unlikely that a user will get caught with

an archive and no way to reproduce the

data.

Ampex Corporation has announced a new R-90

product based on using their VPR-300 D-2

Rotary Digital Video Broadcast Machine for

digital data storage applications. Some of its

pub]ished features are listed in Table 2 below.

u Helical scan recorder

• 15 Megabyte per second transfer rate

• IPl-3 interface

• 300 inch per second shuttle speed

• 150 inch per second search speed

m Accepts three sizes of cassettes

• Small cassette holds 25 gigabytes

• Medium cassette holds 75

gigabytes

• Large cassette holds 165 gigabytes

• Less than one permanent read error

per 1012 bytes read

• Interleaved Reed-Solomon ECC

• Read-after-write with selectable

rewrite

• Automatic reread for soft errors

Table 2. Ampex R-90 Recorder Features

Ampex has initiated an effort to establish an

ANSI standard for the R-90 machine. So far,

to the writers knowledge, no other manufacturer

has announced plans to manufacture a

compatible machine, but all of the ID-I

manufacturers will be represented on the

working group.

1-88

ROTARY

TRANSFORMER

HEAD

DRIVERS

PRE-AMPLIFIERS j HEADS

.::i{ili_iiiiii{ii:i _, :

:i:_:{:7:T:i::".i::':" :7:k::_:_/_"a

:i!::#"_,'_?!_!_!T':..i ,-:Z,ii:_!f_:TN_>.

SEPARATE POWER REGULATORS ON

HEAD WHEEL FOR HEAD DRIVERS AND

PRE-AMPLIFIERS

NUMBER NUMBER

RECORD REPRO HEAD

DATA RAT_ HEADS _ _

200 Mbil/s 4 4 4 4

300 Mbit/s 6 6 6 6

400 Mbit Is 8 8 8 8

Figure 10. Rotary Headwheel for the DCTR-LP

Series ID-1 Machines

July 1991
CASSETTE STORAGE

16 ,urn TAPE 13 t_m TAPE

D-tS 1.1X1011 BITS 1.5X10 _I BITS

D-1M 3.4X10 _ BITS 4.5X10 _ BITS

D-1L 7.6X10 I_ BITS IX1012 BITS

RECORD TIME AT 200 Mbit/s

D-1S 9.5 MINUTES 12 MINUTES

D-1M 30 MINUTES 37 MINUTES

D-1L 66 MINUTES 82 MINUTES

TAPE

COERCIVITY: 850 Oe

ENHANCED IRON OXIDE

USABLE 16 #m THICK

TAPE LENGTH (0.6 MIL)

D-1S 620 FEET

D-1M 1,922 FEET

D-1L 4,298 FEET

13 #m THICK

_JO.5 MIL)

735 FEET

2.319 FEET

5,318 FEET

CASSETTE

SIZE

1.3 IN X6.77 IN X4.29 IN

1.3 IN X10.0 IN X5.9 IN

1.3 IN X14.4 IN X8.1 IN

Figure 11. ANSI ID-1 Tape Cassettes

Figure 12. Datatape ID-1 Laboratory Machine, the DCTR-LP Series

1-89 .h,Iy ]oo
!!{i#i!iiiiiiiiiii!!!{ii!ii

TAPE TRANSPORT UNIT

(TTU)

RECORD/REPRODUCE UNIT

(RRU)

Figure 13. Airborne ID-1 Machine, the DCTR-A120

FUTURE DEVELOPMENT

New and exciting developments are evolving

from research in magnetic tape recording,

particularly with respect to tape and magnetic

heads.

It seems that everywhere you turn there ts a

new recorder product using metal particle J400

or I500 Oersted tape, e.g., 4mm DAT, 8mm,

1/2" M-2/D-3, and 19ram D-2. Since the

magnetic field required to magnetically saturate

the metal particle tape is higher than for

conventional tapes, new heads are required.

Ferrite heads saturate at lower field strengths.

Accordingly, new heads such as metal-in-gap

heads have been widely used.

DATATAPE and Kodak Research Laboratories

have developed new metal laminated heads

which work very well with higher coercivity

metal particle tape. These heads have

permitted an increase of per channel data rates

from 50 to 200 megabits per channel. This

means that a machine with 8-record and

8-reproduce channels will be able to operate at

1,600 megabits per second (200 Megabytes per

second), a rate substantially higher than that

required for HDTV.

Vv'e are following closely, on-going development

of barium-ferrite as well as metal particle tape,

and we look forward to the panel discussion at

this conference.

SUMMARY

The machines required for storage and retrieval

of bit files of any length are more demanding

than those designed for streaming disk back-up

or continuous video recording. Data integrity

and reliability are absolute requirements. In

addition, data recorded on a cassette in one

machine must be reproducible in another

machine.

To achieve these goals, great care must be

exercised in the design of tape guidance and

servo coupling between the scanner control

track, the tape drive capstan and reel motors;

but most importantly, designs must be generous

where it also counts, i,e., track width and bit

density.

All tape recorders experience errors when

writing and reading data to and from magnetic

tape. The approach must be to minimize the

factors which contribute to errors (tape quality

and tracking) and to incorporate robust error

correction means to improve performance

(interleaving, coding, and write-read and

rewrite).

1-90 .ttdy 199 t
The ANSI ID-1/DD-1 machines incorporate the

desirable features for current generation high

speed, high capacity digital data recorders. The

next year should prove to be very exciting as

the new generation of 19-ram machines enter

service in data storage applications.

ACKNOWLEDGMENTS

The writer is indebted to the following

individuals who contributed to the editorial

review of this paper: Hank Tobin, Norris Huse,

Ray Aires, Bill Bullers, Leo Van Lahr, Mike

Trcka and Joe Trost. Credit is also due to

Joyce Smulo and Eve FitzGerald for generating

the reproducible copy on a very tight schedule.

REFERENCES

1 Mukherjee, Biswanath, "Integrated

Voice-Data Communications over

High-Speed Fiber Optic Networks,"

Computer, IEEE Computer Society,

February 1991, pp. 49-57.

2 The Top 1000 U.S. Companies,

Business Week, 1991 Special Issue,

1991, pp. 100-208

3 Wood, Roger, "Denser Magnetic

Memory," IEEE Spectrum, May 1990,

pp. 32-38

9

Advertisement by Seagate, Computer

Technology Review, May 1991, pp.

24-25.

Kryder, Mark R. and Seger, Paul J.,

"The special section on Magnetic

Information Storage Technology," Guest

Editor, Proceedings of IEEE, Vol 74,

No. 11, Nov. 1986, pp. 1475-1476.

Mallinson, John C., "Achievements in

Rotary Head Magnetic Recording,"

Proceedings of the IEEE, Vol. 78, No.

6, 1990, pp. 1004-1006.

Cannon, Max R. and Seger, Paul J.,

"Data Storage on Tape." Magnetic

Recording Handbook, C. Dennis Mee

and Eric D. Daniel, McGraw-Hill, 1990,

pp. 815-882.

Mallinson, John G., "Magnetic Tape

Recording: Archival Considerations,"

Tenth IEEE Symposium on Mass

Storage Systems, IEEE Catalog No.

90CH2844-9, May 1990, pp. 58-60.

Katzive, Bob, "Product Projections,"

IIST Workshop VI, Lake Arrowhead,

October, 1990, Session VII, p. 2.

1-91 July 1991
!

i
f

MAGNETIC TAPE

HARRISS ROBINSON

IATATAP| IIICORP||ATILrl

23 JULY 1991

J

f

OVERVIEW

• DATA STORAGE AND PROCESSING ENVIRONMENT

• MA_ TAPE TECHNICAL PERS_CTM_

• CONTEMPORARY DIGn'AL DATA RECORDERS

• HIGH _ 19ram HELICAL SCAN

DIGITAL DATA RECORDERS

• FLmJ_ [:::E'WLOPMENT

HAJ_ISS ROINNSON DATATAPf '_0¢1_A1"_0 J

PRECEDING PAGE BLANK NOT FILMED

1-93
DATA STORAGE AND PROCESSING ENVIRONMENT

MOVETO VISUALIZATIONREQUIRES

• VERY LARGE FILES FOR IMAGES VS ALPHANUMERIC F,.ES (1000 TO 1)

• CHANGES IN DESIGN OF PROCESSORS

IMPROVED DATA COMMUNICATIONS TI-ROJC_ NETWORK BUSES

HIGH DATA RATES

PACKerSwrrcHe_GPROTOCOLS

FIBER CHANNELS

D_sTmu'rso C,o_NG

MORE ANO LARGER MASS STORAGE SYSTEm

HARR1SS ROBINSON DATATAPE tNCOI_f_OlU, I"EO J

f

MAGNETIC RECORDING IS A ROBUST TECHNOLOGY

• _AL SALES OF MAGNETIC RECORDCqG PR_TS EXCEED

$50 BtUC_

• IBM Is LARGESTUS COMPANYINTERMSOF MARKETVALUE"

-- $74,996,000,000 (GM W/EDS ANOHAC -- $29,838,000,000)

• SEAGATESH_ SEVENMUJON D_ I:)RM_SIN 1990

• SALESC_FMAO=flEI_TAPEPRODUCTSSOAREDIN 1990

(BM STORAGE TECHNOLOGY, EXABYTE, ET. AL.)

* Business Week, May 1991

_-_SS nOIIIt_S(_ 0ATAI"AP[ IN_(_III(_I_I'Tt._ J

2 -'- C :

1-94
MAGNETIC TAPE TECHNICAL PERSPECTIVE

WHICH CAME FIRST MAGNEnC STORAGE OR COMPUTERS?

MAGNETICRECORDERSSTORE DATA DIFFERENTLYTHAN

SEMIC_TOR MEMORIES

• SEMICONDUCTOR MEMORIES STORE 1S AND 0S BY

CONTROLLINGTHE STATE OF _I4mC_$1OUCTOR OLrVICES

• MAGNETIC RECORDERSSTORE 1S AND 0S AS OOMACMSOF SM_NING

ELECTRONS_ A T_N LAYEROF FERROMAGWL_CPARTCLES

HARRtSS ROBINSON DATATAPE INCORPORATEO J

f

MAGNETIC TAPE TECHNICAL PERSPECTIVE

• _ RECORDI_ TECI-NQLES

• LONGffUOINAL TRACKS (g, 18, 28, 42. 84 TRACKS)

ROT/mY SC._N_

• HELICAL

• TR,u_sv_sE

..J

MAGNE'nc TA_ RECOROI_ TECHN_JES

HARRISS ROl_qSO_ DAr*rJu_ _COAPORATE1D

1-95
HISTORICAL PERSPECTIVE

• FIRST MA_ RECORDING BY PAUl.SEN 1898

PLAYBACK

(Magnetic Recording Handbook, by Marvin Camras)

HARRISS ROBINSON OATATk_ l_'r1_D J

f

HISTORICAL PERSPECTIVE (Cont'd)

• LATE 1940S - BE_ WEESPREAD USE OF LONCenJDN_

ANALOG RE_ OF COMPLEX WAVEFORMS (INSTRUlVENTATION,

ALEXO,AND V_EO)

• EARLY 1950S - 7.TRACKAND LATER9-TRACKL_

RE_ SELECTED FOR COMR.rTI_ DIGITAL DATA RECOR_

• 1956 AMPEX INVENTEDTRANSVERSESCAN r-_ V[)EO

BROADCASllNG TV RECORDERS

• 1958 - RCA INTROOUCE#TRANSVERSESCAN VEEO BROADCAST

MACHNES FOR "rv BROA_AST

• 1968 - DAMRON, et. al., EARLESTUSE OF ROTARY HEADS TO

ACHEVE HC.,HI_TION DENSITYFORCOMPUTERDATA (A_x)

HARRIS$ ROEI_SON OJT*TAPE INCORPORATED

1-96
f

HISTORICAL PERSPECTIVE (Cont'd)

1970s AND 1980S -

• 1/4-INCH Am 112-,4CH TA_ CA_ES WERe INTROOUCED

FOR LON(_'TIJDn_ALDIGITALDATA RECORDING

• DATATAPE INTROOUCLmSYSTEM 600, AND 84-TRACK D_otrALDATA RECORDER

Wrm _4E_C'rAIIU[RECOROAND RLqmOO(JOERATES FROM 6.25 TO 56 MPS

1980S - DATATAPE INTR_ SEVERAL H_.,H DATA RATE,

H_,H STORAGECAPACnh', HEUCa. SCAN _AL RECORDERS

FOR DOD. (s_z NEXT VO)

• TH! RDCR Is A MAss STORAOE SYSTEMW_H AmOMA'rLrD CASSL='FrEHANO_

• Mozmwo RDCR T_p_ Dm;zs ALso Us_ Wrn4 NEC JUKBOX

• RDCR ALSO USED IN COMMERCIALMAS_ STORAGE SYSTEM SOU) BY

MAssTOR CORPORATION

HARRISS ROBINSON DAI'ATAPE INCORPORATED J

$

f

CONTEMPORARY DIGITAL DATA RECORDERS

3480/3490 IBM, STORAGETECHNOLOGY, et. al.

• L_naur S_.s Vocum PRoouc'r

• 1/2-INCHLONOmJaN_ TA_ (C_llmO_

• FPS-60 Im'm_Ace

• DATA RATE: 3--4

• STO_O! C_AcrrY: 200

• S_J.=sI=_Kmo_ T_,_ Dm,=s: $10,000 To $20,000 EAot

CAm A_OXJMATB.Y $6 F_CN

• Av_a._ul m S_ TEKTM ACL-4000 AUm)mTBD SlX_ S¢Oe

(UP1"O_ CANEI"fES STOR_G OVER 1 I'ER_YI_

KiJmlSll¢IOImsoN 0ATA'r_ mCORPORAI"ED

1-97

w
f

CONTEMPORARY DIGITAL DATA RECORDERS (Cont'd)

• 8-mm HEUCAL SCAN RECORDERS

• MANUFACTUflEDBY EXABY'rE USrNG SONY 8MM TAPE _ WrrH

EXABYI'EELECTRONCS

• SOLD THROUGHSYSTEM INTEGRATORS AND RESELLERSFOR SMALL

COMPUTER DiSK BACK-UPAPmJCATIONS

• SCSI INTERFACE

• STANDARDVERSION

- BURST DATA RATE: 1.5

- STORAGECAPACITY" 2.3 (38

- 812 TRACKSPERiNCH

• I-I_R _ VERSIONS

- BURST DATA PATE: 3.0 Mm'S

- STORAGE CAPACrrY: 5.0 GB

- 1638 TRACKSPER INCH

• USES METAL PARTICLETAPE

• VALUE ADDED SUPPLIERS: MEGATAPE,SUMMUS,et. al.

HARfltSS RO_I_ISON OATATA/_ INCORPORAI"k"D

f

II

CONTEMPORARY DIGITAL DATA RECORDERS (Cont'd)

1/2-INCH METRUM VLDS I'IB._AL SC_N TAPE CAR_ MACH_

• _A_ BY ME'rR(._ _ A MATSUSHTA VHS Tk"_

_m'NME'n_ B_=C'mONK=

• SOLO k VOI.UME D_C'rLY BY ML:TRb_A

• Tn., SCSI-1, VME, ,_o VAX ORB INnB_AClS

• Smxxi _ VERSO.

- DATA P_TI:

- CASSEI-m STO_OI CAPACitY:

• DUAl._ VBmO,

- D,TARATF.:

- C_m STOOGEC_Acn'Y:

1.SMB_

5.2 O8 (10 el AVM_JlI_

3 I_IIIQ

S.2O8 (10 OBAVAI./dN.E)

_VVRITE VERSIONC,BER: 1 _ IN 10,_

COS_T D(x,_ C_mqAF_mc Oxn)eTAME

AvAu_llU_ _ AttrOMA_C CART_O_ _ _ UP TO

6OOC._mm_s

HARRSSS ROB_SO_ O"/'ATAPS _NCORPORAI"I_

1-98
CONTEMPORARY DIGITAL DATA RECORDERS (Cont'd)

l-INCH AMPEX DCRSi TRANSVERSESCAN MACH_E

• DATA RATES UP TO 13.4 MBPSUSINGA 96 MB BUFFER

• STORES47,5 G8 PIERCARTRIDGE

• AVAIt.ABLE WITH EITHER A SERIAL ORS-BITPARALLELTTL INTERFACEAND

RS-232 oR RS-422 Com'MOL Am STAT_ _ACE

• COeALT DORO GAMMA FEm_C Oxme TAR

• THf TAR FORMAT ANOTAR CAm_OOl _ AMPEX P_m_ARY

• SEVERALHUN_EO MACraMES Am W

HARRISS ROBINSON DATATAPE INCORPORATED

f

CONTEMPORARY DIGWAL DATA RECORDERS (Cont'd)

ROCJq-]] I

17 I Ye,_J IJ_ Jg)

TtlcJ P_¢h I 2

HARRISS ROBINS_,N _*,I'*TAPE INCORPOAAT_O

"Jq T,

1-99
CONTEMPORARY DIGITAL DATA RECORDERS (Cont'd)

• 4-mm HELICAL SCAN TAPE CARTRIDGE MACHINES

• AVAILABLEFROM: ARCHIVE, CALIPER, _TAPE, _TREND,

I-IE'VVLE'_PACKARD, HfTACHI, SONY, WANGTEK, WANG DAT, et. al,

• TRANSFER RATES OF 0.1 9 MBPS, READ-,_WRrl"E CAPABILITY 1.25 G8 PER

CAR1TIIOGE, CBER < 1 ERROR IN 10 BITS. SC81-1 ANO PERTEC INTERFACES

• TWO PROPOSED STANDARDS

• HtGHDENSrrY- 61000 BPt AND1869 TPI

• MASSTORM-960 HELICALSCANCARTMACHNE

• UP TO 8 M961 HELKtAL SCAN STORAGE MOOULE8 (_ 110 GI8 EACH

• M-1000 USERCAPACrn' 1.oll ¢,a

• STORES UP TO 6 TERABY'I'ES W/IDATA _I:RE,_SlON

• INFORMATION STORAGE ANO RETRIEVAL ON LINE, CENTRALIZED, ERASABLE, MANm_Me

ATTACHED, SYSTEM MANAGED STORAGE UNIT WITH ,_qq.K_ATION SOFTWARE

• SuP_)wrs FRoM 4 TO 8 JE_vlHOSTS (4.5 MBPS)

_.._ HARRIS$ROelNSON DATATAII_INCO/qPORA'rI_)

HIGH PERFORMANCE 19-ram HELICAL SCAN

DIGITAL TAPE RECORDERS

AF'R,. 1986 - INDUSmYANDGO_ W_ GROLPS

FORMEDTO GENImATEA NEW ANSI STANDARDFORA 19mm

ID-1 Im'mUMENTAT_ RECORDER

USESMPTE STD19-ram D_n'AL VIDEOTV TAPEDm/ES wrrH

EACH MFGFtS NEWLY DE,_='qED DIG_AL DATA ELEC_

• ScAN TRAa(S ON TAPE TO BE CONTINUOUI NSTEAD OF SEGMENTED

COMPONENT VIOEO FOIU_AT

L_ RS 4/5 ECC, SCANBCOCKID, A.NO!'_ _

I_NNOTATN)NTRACKS

C_sm.AY OF CASsrrnls_ BE DI_wrRA_

HARNSSRO6_S_ OAtA_API_WCOI_t_qAI_'D

l-lO0
f

HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• ID-1 WORKING GROUP INCLUDED REPRESENTATIVES FROM

AMPEX

Bow INDUST_ES

DATATAPE INCORPORATED

FAIRCHILD WESTON (NOW LORAL)

HONEYWELL(NOWMETm.M

U.S. Gowm_.m (NASA ANDDOO)

ODETIC$

MEMOReX

RCA (NOWC,e)

SANCXA

SCHLUMBEROER

SONY

• APPROVALOFNEW STD-7 DECBVeER1989

ANSI X 3.175-1990 - 19mm Tw_ ID-1 RE_ INSTm_E_rrAT_ONDmtTALCASSETrt FORMA_SECRETAmAT,COMPttrERANDBusn_SS

EOUn=MENTMANUFACTURERSASSOaATION

HA.q_ss ROelNSON OATATAJ_ _I"L_

f

HIGH PERFORMANCE 19.mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• NEW PROCAJCTS ANkE:X.eqCED IN LAST TWO YEARS BY

GE, METRUM, LORAL, SONY, ANDDATATAPE

• DATATAPE INCOBPORATEDVABU_BLERATE BUFFERTO OPERATE

UNDER PROTOCOL CONTROL FROM MATCHNG ID-1 RECORDER TO

HOST SYSTEM DATA RATES (0 TO 50 IVlBPS)AND PROVIDE

REA_AFnm-WRrrE ANDREWRrTE

• SYSTEM ALSO PROVIDED BY DATATAPE AND OTHERS WrrH

CHI SYSTEMSINTEPE:ACE _ _TeVACZ

io

OCTI_-LP

'E/E4M

- o_irom

vim _vlcE

(raM. SWffCI.I.

w¢ )

HARRISS ROBINSO_ 3ATATAPE INCORIP_)II_ATEO

fEE4M

conual

l-lOl
HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

ANSI X3.175 STANDARD SPECIES _ RECORd, BUT

NON-A_MUTH RECORDERSARE AVAL_LE FOR MIL-STD-2179

MIL-STD-2179 FORMAT

0" AZ_V_TH RECORDING

ANSI IO-1 FORMAT

+15' AZIMUTN RECORDING

HARRISS ROOtNSON DATATAPIE INCOIqPOClATIED

f

HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• I_RF_ P_VETERS OF ANSI ID-I RECORDS_

D-1 400 _e_t_s 300 II_t/s 200 MI_]$

DI"T1R RECORDER RE_ RIECOR{_I

BER Wm.t ERROR IXLO-e W,I[CC

CORRECTION

DRUM OUU_k'TER 2.M IN 295 IN 2iS IN

ACllVE _ _ 257" 254" :IS?"

AZ_UTH 0" .tS" OR O" *1|* OR O*

TRACK PrFCH II MI. (4s _m) 1 8 Ml (4i _/n) 11 ilL (4 _m)

SCANNER RATE 149.9 R/$ 11'3 i R/$ 1T'J.I R/8

NU4IEq OF _8 4 8 I

TAPE VfLO_'I_ 11.3 _ 2_11 IN,,S it.5 IN_

HF.AI_T_TAI_ SPEED 1401 M _13_ _U$ !121 IN_

U$1_I DATA RATE 171 MII_I 400 MI_/I 300 IIIIt/I

TAPE DATA RATE 22S.1 Idl_Uu 533 Mbl_| 4_ MIM/II

INSTANTANEOUS I4[AO 71.7 Idlllt/$ g3 g 1411_1 I_1 Mbll/i

DATA RATE

OeiSffY SO Kb_IN s1' K_U_N 17 _ S7 KI_Um

SPEEOtI_TE _ SlqGU[ SPI[EO I t 8:1 8:1

CHANNEL COOl RA/4DOMIZED i41 IX: _ COOE FOR V_llAI,l iPlI_.

_Sl- ,o-_ ALSO INCt.UOEI RANDOMIZING

lX10 '_ W_CC IX10-'0 W_tCC 1X10-_0 W/_CC

(R/S) (R'S) (R/S)

2111 IN

2Sl"

*IS" OR O*

t8 I. (aS _m)

1T],1 _S

4

1111 llt|

200 ib_US

2U MIBI_II

1"2.0 IIMUs

HAi_IISSROOINSON Oa_a_a_E_NCO_TED

1-102
f

HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

ANSI ID-1 TAPE FORMAT AND DATATAPE DCTR-LP SCANNER

O,CI"R - LIe

_m(k4ER

?S mm

(30")

t 0,.II10 R_

............

allqlllPl¢llll_l_ I.II ,41 11

41mUlll II_

NOTE TOP SPEED OF SCANNER AT 10.380 RI:'M _ HEADS ARE

LITERALLY MOV1NG AT OVER 90 MP_ ALONG A TRACK THAT IS

NARROWER THAN A HUMAN HAIR

HARFUSS ROBINSON OATATAPE II_OI_ORATED

f

HIGH PERFORMANCE 19.mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• ANSI 113-1 RECO_ HEAD USED ON

DCTR-LP SERES RECORDERS

IqlE -AMPC.IPIERI _-II,k_l

© )

00ll m,_

(IMVIIIIIJI I

i, :-:2F,

U

911IA/IATII IIOV_II IWO+.JI_TOIII C_

_ MEL POll HIIAO lYlVllU

Ptlql. +4_VlPClFIIIIll

/ m

m 141m_l • • * •

m I_llal • • i t

11oi_l I I I i

HARRISS ROB+NS"_ Oi_ATAI_E INCO_POI_I"ED

1-103
f

AVERAGE DIAMETER OF A HUMAN HAIR*

(MILS)

M4=

DONOR (SEX)

1. J. UDELL (M)

2. H. ROBINSON (M)

3. L. VAIL (M)

4. a. VIERIA (U)

5. K. STOFFERS (F)

MEASURED BY

J. UDELL L. VAIL D. HOSKINS

2.0

1.4

2.3

2.7

2.3

2.0

1.3

2.3

3,0

2,2

2.0

1.3

2.3

2.7

2.1

MEAN

2.0

1.4

2.3

2.8

2.2

* DATA TAKEN AT DATATAPE 4125/90

AVERAGE Tt-NCKNESS 2.1

(0.053 mm)

HARRIS$ ROBINSON DATATAPE INCOfIPORATED

f

TERMINOLOGY / CONVERSION FACTORS

WOaD AB=EV.

BYTE B

KILOBYTE KB

MEGABYTE IVtB

GB

TERABYTE TB

PETABYTE PB

EXABYI'E Eli

HARBYI"E FIB

BYTES errs

1 8

1,000 8,0OO

1,000,000 8,000,000

etc etc

(PROPOSED HERE TOOAY)

_. BYTES

10

10 a

10 a

10 g

10 _z

10 is

10 _a

10 z'

H/I_AISS ROI_NSO_ O*'tAI'APE INCORPORATED

1-104
f

HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• ANSI ID-1 TAPE CASSETTE

USABLE 16 _rn Ti._'t( T3 _m THICK CAS..rCdE1"_

TAPE LENGTH (0 8 kt¢_ TO 5 J_IL)

O-15 620 FEET 73S FEET 1 3 IN X6 77 IN X4n IN

O-IM _.922 FEET 2 3tg FEET 1.3 _ xto0 _ XS.91M

O-IL 4._ FEET 5.311 FEET 1 3 IN X14.4 IN X_.I IN

¢,,tSSI[I"T[ STOI_OE

111 ,m TA/_ 13 _.m TAPIE

D-IS I IX_O_* IkY$ I SxlO" ll/T$

O-IM | 4_10" roT| 4 S_t0" lIT$

D'IL ? |_(10" IkT_ I_10 _eIIIT I

M_(::_ TIME AT _ Ml_/e

0-15 ! S MINUTES t2 kliN(J'rES

O-IM _ MINUTES 31 141k_TE$

O-It. MI MINUTES |_ J_IB,_/TE$

TAPE

COIRCI_W IL_4)Oo

EHI_4NCEO IFIOq Ol(_lS

DATATAPE ID-1 DCTR-LP

SERIESLABORATORYRECORDER

HARRISS ROINNSON OATATAPE _TI_

f

HIGH PERFORMANCE 19-ram HELICAL SCAN

DIGITAL TAPE RECORDERS

• DATATAPE ID-1 DCTR-A120 SERIES

A_ MIL-E-5400 RECORDERS

TAP1[ 'flUkNSI_N_T _ _ UNIT

HARR1SS _ 0ATATAI_ INCOflP'OflA'I'I_

I

J

1-105
f

HIGH PERFORMANCE 19-mm HELICAL SCAN

DIGITAL TAPE RECORDERS

• ID-1 CONSERVATIVE DESIGN APPROACH

• TRACKSPA_ 0.045ram (0.0018")

• 850 OlmS_D GAMMAFE_=.¢ Oxme TA_

• HIGHDATA RATESACHEVfO TO 50 MBPS

• Mut.T.=t.=SuM_mR oF Eou_m" DI_ TOSTANOAROS

• AMPEX R-90 HEUCALSCANRECORDERBASEDONUSI'_G

AMPEX VPR-300 D-2 ROTARY DIGrr.N. V[)EO BROADCAST

MACH_E FEATURES

• Helical scan recorder

• 15 Megabyte _ second transfer rate

• 1'!-3 Interf=w,e

a 300 inch per second shuttle speed

• 150 inch pe_ secor_l search

• Accepts three sizes of cassettes

• Small cassette holds 25 gigabytes

• Medium caasette _ 75 gigabyt=

• I._'ge ¢u,_Nte holds 165 gigabyte_l

• Less than one permanent reed error per 10_=

I:_es read

• Interleav_l ;=teed-Sek)mon ECC

• Re4Kl-mfl_'-writewith selecta_e rewrite

• Automatic reread for softerrors

HARRISSROe(INSON DATATJJINEINCORPOR&I'E'D i;,.

f

FUTURE DEVELOPMENT

• H___H_ T/_=E

FROM850 OERSTEDTO: TBD

• Hk3H_ HEADS

FROMFERRITETO METAL-I_C-V_,TO ML=r/q._TED

• PER_ DATARATESFROM:

50 TO >200 MBPS Z, 8-_ MA_ WtL BE ABE

TO ORmATE AT OVE]_1,600 MBPS (>200 MBPS), A RATE

SUBSTANTIALLY_ THAN R_ FOR HDTV

HARRISSROe_SO_ 0*T*TAPI__,K_O$11=_q$,TED

1-106
f

SUMMARY

• MACHINES REQUIRED FOR STORAGE OF Brr-RLES OF ANY LENGTH

ARE MORE DEMANDING THAN STREAMING DISK BACK-UP OR

CONTINUOUS VIDEO RECORD_IG

• DATA INTEGRITY AND RELIABILITY ARE ABSOLUTE REQUIREMENTS

• DATA RECORDED ON A CASSE'n'E IN ONE MACHINE MUST BE REPRODUCIBLE

IN ANOTHER MACHINE

• DESIGNS SHOULD BE GENEROUS, e.g., TRACK WIDTH AND

BIT DENSITY

• SOUND APPROACH ISTO MIN_LTE FACTORS WHICH CONTRIBUTE

TO ERRORS (TAPE QUALITY AND TRA_) AND INCORPORATE

ROBUST ERROR CORRECTION (INTERLEAVING, CODING, AND

WRITE-READ AND REWRITE).

• ANSI ID-1/DD-1 MACHINESINCORPORATETHEDESIRABLE FEATURES

FOR CURRENT GENERATION H_GH SPEED, H_GH CAPACn'Y

DIGITAL DATA RECORDERS.

J

HARRISS ROBINSON DATATAPE INCORPORATED

_Q

l-107

N93-13136

Storage System Software Solutions

For High-End User Needs

Carole B. Hogan

Director of UniTree Technical Development

Distributed Computing Solutions, General Atomics

San Diego, California

PRECEDING PAGE BLANK NOT FILMED

1-109
Storage System Software Solutions For High-End User Needs

Abstract

Today's high-end storage user is one that requires rapid access to a reliable terabytecapacity storage system running in a distributed environment. This paper discusses

conventional storage system software and concludes that this software, designed for other

purposes, cannot meet high-end storage requirements. The paper also reviews the philosophy

and design of evolving storage system software. It concludes that this new software, designed

with high-end requirements in mind, provides the potential for solving not only the storage

needs of today but those of the foreseeable future as well.

Introduction

Since the days of computer infancy, people have used computers to generate long-term

data, i.e., data that they desired to access over extended periods of time. To store this data and

to permit access to it, computers included a system of storage hardware and storage software.

Generally, these storage systems provided similar services to all users. The storage hardware

consisted of a single storage media type. The storage software provided a convenient interface

for users to access and manage data stored on the hardware media.

As the development and use of computers became more specialized and sophisticated,

storage needs of users began to differ. Some user needs were simple, for example, large numbers

of small fries accessed frequently. Other user needs were more demanding, fewer numbers of

large fries that were accessed with varying frequencies. Even though User storage needs were

diverging, storage systems generally continued to offer the same general services, failing to

keep pace with differing user requirements.

Today, user storage needs are continuing to diverge and are doing so at a faster rate than

in the past. Conventional storage systems, i.e., the systems that have grown up with the first

generations of computer users, can no longer even pretend to meet the differing storage needs of

current users. However, new storage systems are being provided that can meet the needs of a

variety of storage users in today's computing environments and can also adapt to changing

needs in the environments of tomorrow.

The remainder of this paper focuses on the particular storage software needs of highend users, conventional storage systems software and the shortcomings that prevent it from

meeting these needs, and the features of the newer storage system software that make it an

ideal solution for this user community.

Storage Needs

In general, computer users wlth high-end needs are those that generate terabytes of

long-term data from hlgh-performance processors. Working in a network environment, these

users require the data to be placed in a reliable storage system that can be rapidly and

conveniently accessed from several points in the network. Because of the finite budgets, the

storage system must be able to provide its services by efficient use of continually-advancing

storage technology.

While high-end users have several needs from their storage system software, their

primary needs are reliability, capacity, performance, hardware flexibility, software flexibility

and reasonable cost. Each of these needs is discussed in turn.

ILII0
Reliability

Reliability is the capability to guarantee that data accepted for storage will be returned

in the same state in which it was received, and the capability to provide continuous storage

system availability.

The data integrity component of the reliability need, i.e., returning data to the user in

the same state in which it was stored, is the traditional hallmark of storage system software,

particularly for storage systems designed as long-term archives. If users cannot trust the

storage system software to provide data integrity then, regardless of its other attributes, the

system is not useful to them.

The system availability aspect of the reliability need is particularly important for realtime applications such as seismic monitoring programs. Storage system software must

provide continuous storage system service in order for these applications to successfully store

the data received from the real-tlme source.

Caoaclty

Capacity is the capability to store increasing amounts of data upon demand.

The capacity requirement is primarily a software requirement to keep pace with

developing hardware technology that permits the generation of larger and larger quantities of

data. For example, the processor and main memory technology provided in computers from

which users generate data is continually improving in speed and size. This allows users to

generate more data in shorter periods of time.

Other types of sophistication in data generation techniques also require increasing

storage capacity, for example, satellite-based data generation can result in petabyte capacity

requirements. Storage system software must be able to meet these capacity requirements upon

demand, in order to be useful in these types of computing environments.

The capacity requirement also prevents the placement of limitations on the numbers of

files that can be stored or the size of the files that are stored in the system.

Performance

Performance is the capability to provide access to data as quickly as possible.

The need for fast response from storage system software, both on read and write

accesses, is especially important when users generate large amounts of data in a network, or

distributed, environment. In such an environment, the storage system software usually runs

on a processor or processors dedicated to its use while users access the system from a variety of

other computers. So in order for the software to provide optimum performance, it must be

efficient enough to utilize high-speed networks and high-speed storage devices at their

maximum performance capability.

Hardware Flexibility

Hardware flexibility is the capability to adapt to new storage media, and the capability

to manage multiple media in the same storage system.

Advances in hardware technology continue to provide faster, cheaper, greater-capacity

storage media. In order for users to receive the benefit of these advances in technology, the

storage system software must be flexible enough to store, retrieve and manage data on the new

media with only minor modifications to the software.

l-Ill
Storagesystemsoftwaremust alsobeableto managedifferenthardwaremediatypesin

the samestoragesystemto giveusers the option of utilizing mediawith different storageand

cost/performancecharacteristics.

_gftware Flexibility

Software flexibility is the capability to operate on several software platforms, and the

capability to adapt to new application requirements.

Generally, storage system software is designed to interface with the software operating

system on a given processor. Because users are often best served by periodic upgrades to

different storage processors with different operating systems, the storage system software must

be flexible enough to run on a variety of software platforms.

Storage system software must also be able to adapt to new application requirements

such as providing the means to identify fries by attribute rather than by more traditional

means.

Reasonable Cost

Reasonable Cost is the capability to provide the maximum amount of storage within

defined budget guidelines.

To be cost effective, the storage systems software must be able to utilize cost-reducing

advances in storage hardware technology such as managing cheaper storage media types as

they become available. Also. storage system software that can utilize robotically-mounted

storage media will permit reduction in the labor costs associated with manually mounted

media.

Figure 1 presents an example of a network computing environment that depicts a

storage solution for high-end storage needs.

(MAC.,.E; MAC.I.EJ //fl MA ,.E)

MULTIPLE TERABYTE CAPACITY

00

MAGNETIC OPTICAL ON-LINE OFF-LINE

DISK DISK TAPE TAPE

HIGH SPEED

NETWORK

(Figure 1)

1-I12
ConventionalStorageSystemSoftware

This section of the paper describe conventional storage system software and discusses

the shortcomings inherent in this software that prevent it from meeting today's high-end

storage needs.

Features

In general, conventional storage system software is designed to manage large amounts

of data over long periods of time, and to provide convenient user access to the data. Convenient

user access is provided through two abstractions, a file and a human name to identify a file.

The file abstraction allows users to manage their data in convenient units rather than

as individual bits. A human name for a file permits users to access the file with that name

rather than requiring them to supply the actual address on the storage media where the file is

stored. The conventional human name for a file is a directory pathname.

Figure 2 presents a sample directory structure of the UNIX file system, a conventional

storage system familiar to many users. The two files in the directory structure shown have the

human names "/usr/long/datafile" and "/usr/sauer/textfile".

/

bin etc usr

long sauer

dat!file textlile

(Figure 2)

Typically, conventional storage system software provide operations on files such as create,

open, write, read, and close. It also manages fries by storing them on a single storage media

type. The conventional storage media is magnetic disk.

1-113
Figure 3 showsthe hardwareconfigurationfor the conventionalUNIXfile system.

STORAGE

PROCESSOR

MAGNETIC S

(Figure 3)

Meeting Storag_e Needs

Generally, conventional storage system software fails to fulfill each of today's high-end

storage requirements because it is designed to meet simpler storage needs in simpler computing

environments. Some of its specific shortcomings are discussed here.

Reliability

Storage system software provides data integrity by using algorithms that function

correctly and by providing mechanisms that preserve data when hardware media fails. While

conventional system algorithms function correctly, the software makes no provision for

protecting data from media failure, such as providing redundant copies on different media or

automatic backup procedures. Generally, assurance of data integrity in these systems is only

as good as the reliability of the storage hardware media and the frequency of manual backup of

the data to other media.

Further, providing continuous system availability is not a feature of conventional

storage system software. For example, the flexibility to manage a single storage database from

two copies of the same software running on two different processors is absent. Such a feature

would permit continuous service across processor failure.

Capacity

The capacity to meet increasing storage capacity demands is also absent form

conventional storage system software due to built-in limitations in the software. First,

capacity is limited because the software manages only magnetic disk as the storage hardware

media. There is a limit to the amount of disk that can be attached to any processor.

Second, capacity is also limited because conventional software is not designed to

continue writing a file to another disk with available space when the first disk becomes full.

1-114
This limitation is not only an inconvenience to users and system administrators but it also

means that the largest file in the system is restricted to the size of the largest dislc

Third, total storage system capacity is also limited by a software restriction on the

number of data blocks that can be addressed in the system. This restriction hold regardless of

the number of disks managed by the software. Usually, this addressing restriction limits total

storage capacity to hundreds of gigabytes on even the largest computers.

Performance

The greatest cause of performance degradation in conventional storage systems is the

necessity for manual storage media management. When magnetic disks become full of data, a

human operator must off-load the data to other media, such as tape, in order to create space on

the disk for storing more flies. Later, when a user desires to access a file that has been moved to

tape, the operator must first locate the tape and read the file from the tape back to disk. Once

the file is on disk again, the user can access it.

Any software system that requires manual media management will not perform

satisfactorily in today's high-end computing environment.

Hardware Flexibility

The hardware flexibility requirement of adapting to new storage hardware media and

of managing multiple media types in the same storage system software. Conventional

software, as stated above, manages only magnetic disk as the storage hardware media.

Software Flexibility

Conventional storage system software is designed to run on only one type of operating

system. Therefore, the same software cannot be used to manage user data if the storage

processor is upgraded to one that provides a different operating system. In this case, another

brand of storage system software must be used. This usually requires reformatting data from

the old system format to the new system format.

Also, conventional storage system software lacks the flexibility to adapt to new

application requirements such as new naming conventions for flies. Because the conventional

mechanism for naming files, i.e., the directory structure, is intertwined with file management,

a new naming mechanism, such as a database management system, will require a different

brand of storage system software.

Reasonable Cost

Conventional storage system software keeps storage costs relatively high by managing

only magnetic disk and by requiring labor-intensive manual storage media management.

The remainder of the paper discusses the philosophy, features and architecture of

today's evolving storage system software, and how this software can meet the storage needs of

high-end users for the foreseeable future.

Evolving Storage System Software

Recognizing the need for storage system software that is capable of responding to user

needs in the computing environments of today and tomorrow, the IEEE Technical Committee

on Mass Storage Systems and Technology and the IEEE Storage System Standards Working

Group are developing a model for mass storage systems. In its most recent published version,

the Mass Storage System Reference Model I advocates concepts and an architecture that will

allow storage system software to meet user needs for the foreseeable future.

1-115
Much of today's evolving storage system software takes its direction form the Mass

Storage System Reference Model. Although the Model is not specifically described in this

paper, its influence is visible in the philosophy, features and architecture of the evolving

storage systems software discussed here.

Philosgphy

The philosophy of evolving storage system software states that the software must be

flexible enough to meet current application needs and to be easily adapted to changing

application needs and hardware technology advances. This philosophy, seemingly

unremarkable, deserves special notice because it is the first time storage software has been

dedicated to meeting current and changing needs and technology. Certainly, conventional

storage system software is designed without this motivation in mind and, as a result, fails to

saUsfy high-end user needs.

Key Features

There are several key features of evolving storage system software. These features are

described here. Taken together, they provide a flexible storage system.

Redundancy

Redundancy is the ability to continue storage service in the event of hardware failure

such as processor or storage media failure. If a storage processor fails, access to the storage

system is threatened. If hardware media fails, access to data on that media is threatened.

Evolving storage system software is designed to allow continuance of service in the

event of processor failure by providing the capability to access the same storage database from

a standby processor. If the primary processor on which the storage system is operating fails,

the standby processor can be started and the storage system run from that hardware platform.

Evolving storage system software also provide the capability to store redundant copies

of data on different devices of the same media such as different tapes. If this feature is taken

advantage of and a tape fails, data is not lost because copies exist on other tapes.

No Software Limits

A lack of software limits means that the capacity of the storage system is limited not by

the software, but only by the amount of storage hardware media allocated to it.

Evolving storage system software places no limitation on the length of files, the

number of files, the lengths of human names for files or the number or size of directories, it

that is the naming mechanism, that the storage system can contain. Unrestricted file length is

particularly important since it means that a single file can span devices of the same storage

media type such as disk or tape, and is no longer limited to the capacity of a single disk or tape.

Storage Media Hierarchy

Evolving storage system software has the capability to manage a storage media

hierarchy. A hierarchy is different types of storage media configured in a layered or

hierarchical fashion and managed as part of a single storage system. In general, the media in a

storage hierarchy are layered according to speed of access, with the faster and generally more

expensive media in the higher layers and the slower and generally cheaper media in the lower

layers of the hierarchy.

1-116
For example,a storage hierarchy might consist of magnetic disk, optical disk, on-line

magnetic tape and off-llne magnetic tape. Data is moved between these layers according to siteconfigurable parameters and user access.

Automatic Migration and Caching

Evolving storage system software offers the features of migration and caching to

automatically move data between the layers of the storage media hierarchy. Migration is the

movement of data downward in the layers of the hierarchy. Caching is the movement of data

upward in the layers of the hierarchy. The software moves the data automatically, without

human operator intervention, according to site-configurable parameters and user access.

Migration parameters determine how often files are migrated to lower layers and which

files are migrated. Caching upward in the hierarchy is triggered by user access of files that

have migrated to lower levels. Because of migration and caching, active files, i.e., those

currently being accessed, reside on the higher, faster access layers of the hierarchy, while

inactive files reside on the lower, slower media.

Distributability

Evolving storage system software consists of modules that are capable of being

distributed among several processor in a network environment. This means that the storage

system software is not confined to a single processor but can run on several processors

simultaneously as part of a single storage system. Distributabflity permits load balancing

among components of the system and faster access to data.

Separation of Control and Data

User access to a storage system consists of commands transmitting data (e.g., write

commands) and commands receiving data (e.g., read commands). Each command consists of

two parts, control and data. The control component is the action to be taken, e.g., write or read.

The data component is the actual data to be written or read.

Evolving storage system software separates the control and data components of storage

access commands into two distinct entities that can be transmitted separately to and from the

storage system. This separation permits control and data to flow over separate network paths.

For example, control can flow over slower network paths while data can flow over

faster network paths. This type of separation permits faster access to the storage system.

Since data transmissions are generally much larger than control transmissions, transmitting

data over a separate path or paths can result in faster performance in general.

Extensibillty

Evolving storage system software is extensible. Extensibflity is the capability to easily

integrate additional types of storage media into the storage media hierarchy. Easy integration

of additional media permits sites to take advantage of new storage hardware technology as it

develops.

For example, a site may begin with a storage media hierarchy consisting of magnetic

disk, on-line tape and off-line tape. Because of the extensibility of the storage software, optical

disk can be integrated into the hierarchy, for example, between the magnetic disk and on-line

tape layers, when the site decides to take advantage of the features offered by optical disk.

Separate Naming Mechanism

Evolving storage system software is designed to easily adapt to new naming

conventions so that users can access their data in the manner that is most efficient for their

1-117
applications. For example, if applications at a given site generate many thousands of files,

naming files by directory pathname can become inefficient. Instead, naming files by attribute

such as time of creation may be preferred.

Evolving storage system software will permit this transition in naming mechanism

from directory pathname to file attribute because the software modules that map names to files

are separate from , and peripheral to, the modules that manage the files. Therefore, to

transition to a new naming mechanism means only to change a few peripheral modules rather

than the entire storage system software.

Portability

Evolving storage system software is portable. It is designed to run on a variety of

software operating systems. This means that if the storage processor is upgraded to a different

manufacturer with a different operating system. It also means that the same storage software

can manage a single distributed storage system by running on a variety of different processors

with different operating systems.

Architecture

The architecture of evolving storage system software is presented here graphically.

Figure 4 shows the software and hardware layers in a sample storage media hierarchy. Each

layer of media is managed by a different set of software modules.

I

0

N

STORAGESYSTEM

°

C LAYER SOFTWARE Q Disk

H

, I

G. LAYERSOFTWARE @o°4,°. Tape

I

A

Magnetic

Disk

Off-line

Tape

(Figure 4)

1-118
Figure 5 showsthe separatenetworkpaths that control and data can take between the

user and the storage system. In this Figure, data is stored in a three-layer hierarchy, consisting

of a network-attached disk array, standard magnetic disk and tape. The last two layers in the

hierarchy are attached to the storage processor. Storage system software is running on the

disk array controller as well as the storage processor itself. In this way, data can flow directly

between the user machine and the disk array without passing through the storage machine.

USER )

MACHINE J

DATA

STORAGE

SYSTEM

DATA

NETWORK-ATtACHED

DISK ARRAY

STANDARD

MAGNETIC DISK

TAPE

FACILITIES

Meeting Storage Needs

(l:igur¢ 5)

The features and architecture of evolving storage system software permit it to meet the

storage needs of high-end computer users. The manner in which the software meets these needs

is discussed here.

Reliability

System availability and data integrity are provided by the redundancy features of

evolving storage system software. Redundancy provided the capability to continue service

from a standby processor. It also preserves data in the event of damage or loss of a storage

media device such as a tape by providing the capability of storing multiple copies of the same

data on different tapes.

Capacity

Evolving storage system software provides the potential for unlimited storage capacity

by managing a hierarchy of storage media and by a lack of limits in the number of files that

can be stored, the size of files that can be stored, and so forth. Multi-media management in a

hierarchical fashion allows tape to be included in the storage system. Tape as a storage

medium, coupled with a lack of limitation in file size and numbers, means that the system

capacity can grow to as many tapes as a site purchases.

1-119
Performance

Evolving storage system software provides performance through the features of

automatic migration and caching, separation of control and data and distributability.

Automatic migration and caching eliminate the performance degradation caused by

conventional manual media management. Separation of control and data permit data to flow

to and from the storage system over faster network paths, improving performance in general.

Distributability allows components or layers of the storage software to run on different

processors, permitting load balancing and faster access to the system as a whole.

Hardware Flexibility

The extensibflity feature allows evolving storage system software to provide hardware

flexibility. With this flexibility, new storage media can be integrated into the storage

hierarchy. The ability to integrate new media permits users to take advantage of advancing

hardware technology.

Software Flexibility

Software Flexibility is provided by several features of evolving storage system software,

including a lack of software limitations, separate modules that map human file names to the

files themselves, distributability and portability. Portability is the flexibility to run on a

variety of software operating systems.

Reasonable Cost

Reasonable cost is provided by evolving storage system software through the features of

storage media hierarchy management, automatic migration and caching, extensibility and

portability. Managing data through a storage media hierarchy means that less money need be

spent on expensive storage media because only active files will be stored on this higher layers

in the hierarchy. Generally, active files are a small subset of all files in a storage system.

Automatic migration and caching eliminates the cost associated with manual storage media

management.

Extensibility allows cheaper storage media to be integrated into the system as it

becomes available. Portability accommodates less expensive open system solutions to storage

needs since the same storage software can run on a variety of software platforms that can be

combined into a single storage system.

Figure 6 shows an example of an evolving storage system managing storage needs in a

high-end, distributed computing environment. In this example, the naming mechanism is a

database management system. The layers of the storage hierarchy consist of a disk array,

optical disk and on-line and off-line tape. These layers are distributed among different

processors in the network. Redundancy is provided in the optical disk layer of the storage

hierarchy by a standby processor (dotted line) and redundant sets of optical disk.

1-120

i

i
I

REDUNDANT PROCESSORS

AND STORAGE MEDIA

NETWORK

(Figure6)

Conclusion

Users in computing environments with high-end storage requirements must turn away

from using conventional storage system software if these requirements are to be met.

Conventional software, designed for simpler computing environments with simpler storage

requirements, cannot satisfy today's high-end storage needs.

Evolving storage system software, influenced by the IEEE Mass Storage System

Reference Model, is designed to meet high-end storage requirements for the foreseeable future.

It is in these systems that today's high-end users will find solutions to their storage software

needs.

Acknowledgement

The contributions of Michael Hardy, Products Manager,

Solutions. to this paper are gratefully acknowledged.

Ref_c_

Distributed Computing

I. Sam Coleman and Steve Miller, "Mass Storage System Reference Model: Version 4 (May,

1990)," Tenth IEEE Symposium On Mass Storage Systems, Monterey, California, May,

1990.

1-121

Storage System Solutions

NSSDC Conference on Mass Storage Systems

Carole B. Hogan

Director of UniTree Technical Development

Distributed Computing Solutions (DISCOS)

General Atomics

DISCOS Division

July 23, 1991

Overview:

• Storage system definition

• Storage needs

• Conventional storage systems

• Evolving storage systems

PRECEDING PAGE BLANK NOT FILMED

1-123
Storage System Definition:

• Facility that

• manages

large amounts of data

over long periods of time

• provides

convenient use of data

Storage Needs:

• Reliable storage

• Large amounts of data

• Rapid response

• Hardware flexibility

• Software flexibility

• Reasonable cost

1-124
f

81FOR_,@I! Ii?II?I!II 811)I-11110111

Reliable Storage:

• Capability to provide system availability

and data integrity

• real-time applications

• long-term archive

Large Amounts of Data:

• Capacity to store and provide access to

increasing amounts of data

• satellite-based data acquisition

• faster processors

1-125
Rapid Response:

• Capability to provide access to data as

quickly as possible

• high-speed networks

• high-speed storage devices

Hardware: Flexibility:

• Capability to adapt to new storage media

• optical-based

• helical scan tape

1-126
m

w

Software Flexibility:

• Capability to operate on several software

platforms

• Capability to adapt to new application

requirements

• database management system access

Reasonable Cost:

• Provide maximum amount of storage

within budget guidelines

• automated storage media

management

1-127
IM.TELUTE (_

I

I MULTIPLE STORAGE TERABY'rE SYSTEMCAPACITY

Conventional Storage Systems:

• Description

• Example

• Shortcomings

1__i28 _=

J
Conventional Storage System Description:

• Provides

• long term storage and retrieval of user data

• file abstraction for users to manage data

• directory pathname as the mechanism to name

files

• open, write, read, and close operations on files

• management of magnetic disk storage media

for files

Conventional Storage System Example:

• UNIX File System

STORAGE

SYSTEM

1-129
Conventional Storage System Example:

• UNIX File System

bin etc usr

long sauer

I I

datafile textfile

Reliability:

• Only as good as

• reliability of magnetic disk

• frequency of backup
Conventional Storage System Shortcomings:

• Reliability

• Capacity

• Performance

• Hardware flexlbllity

• Software flexibility

• Cost

Capacity:

• Manages single storage media type

- few per machine

• Provldes no mechanlsm to contlnue wrltlng to another

disk which has available space

- llmlted file slze

• Uses software feature that limits total capacity

- lOOs of glgabytes

1-131
Performance:

• Manual storage media management

'operator off'loading data from disk to

tape and back again

Hardware Flexibility:

• Magnetic disk as the only storage

media type

1-132
Software Flexibility:

• No capability to adapt to new application

requirements such as new naming

conventions

Cost:

• More and more expensive disk

• Labor-intensive storage media

management

1-133
IIII(i)IiI_(iII! 8711YII II(i)I.I!III0111

Evolving Storage Systems:

• Philosophy

• Key features

• Architecture

• Meeting storage needs

• Example

IIIF@III_@I! IIVSYI!III _:@I.IWi'I©III

Philosophy:

• Flexible storage system that meets

current application needs and is easily

adapted to changing application needs

and hardware technology advances

!

1-134
Key Features:

• IEEE Mass Storage System Reference Model

• Redundancy

• No software limits

• Storage media hierarchy

• Automatic migration and caching

• Distributability

• Separation of control and data

• Extensibility

• Separate naming mechanism

• Portability

• Redundancy:

• The ability to continue service in the

event of hardware failure such as

processor or storage media failure

1-135
No Software Limits:

• Unlimited length files

• Unlimited number of files

• Unlimited length file names

• Unlimited number of directories

gY@IR_@_ gVgY_l_ g©B,B!_@Ng

Storage Media Hierarchy:

• Different types of storage media

configured in a layered or

hierarchical fashion and managed

as a single storage system

1-136
Automatic Migration and Caching:

• Movement of data between the media

layers of the storage hierarchy according

to administrative policy

• Migration is data movement downward in

the hierarchy

• Caching is data movement upward in the

hierarchy

Distributability:

• Storage system components running on

different processors within a network

1-137
Separation of Control and Data:

• The ability to transmit control and data

over separate network paths

Extensibility:

• The ability to easily integrate additional

types of storage media into the storage

hierarchy

1-138
Separate Naming Mechanism:

• The ability to easily adapt to new

naming conventions

Portability:

• The ability to run on a variety of

software platforms

1-139
81Y@ilIA@II !IVI!IFIIII II@I.I_I@I_Ii

Architecture:

M

G, c

R C

A H

0, G (

N

(

LEVEL SOFTWARE

I

STORAGE SYSTEM 1

LEVEL SOFTWARE

Magnetic

Disk

Optical

Disk

On-line

Tape

Off-line Tape

Architecture:

T / SYSTEM I

1-140
Meeting Storage Needs:

• Reliability

• Capacity

• Performance

• Hardware flexibility

• Software flexibility

• Reasonable cost

IIIIOIRIII! IIYIIYI!III IIOI.IYIOI_III

• Reliability:

• Redundancy

• Capacity:

• Storage media hierarchy

• No software limits

1-141
• Performance:

• Automatic migration and caching

• Separation of control and data

• Distributability

• Hardware Flexibility:

• Extensibility

• Software Flexibility:

• No software limits

• Separate naming mechanism

• Dlstrlbutabillty

• Portablllty

• Reasonable Cost:

• Storage media hlerarchy

• Automatic migration and caching

• Extensibility

• Portability

1-142
"d##/

(SSLS) J

I

I

®®

1-143

N93-13137

File Servers, Networking, and Supercomputers

Reagan W. Moore

San Diego Supercomputer Center

San Diego, California

Abstract

One of the major tasks of a supercomputer center is managing the massive amount of data

generated by application codes. A data flow analysis of the San Diego Supercomputer

Center is presented that illustrates the hierarchical data buffering/caching capacity

requirements and the associated I/O throughput requirements needed to sustain file

service and archival storage. Usage paradigms are examined for both tightly-coupled

and loosely-coupled file servers linked to the supercomputer by high-speed networks.

Introduction

The file server capacity requirements are most strongly driven by the CPU power of the

central computing engine. The workload that can be sustained on the supercomputer is

ultimately limited by the ability to handle the resulting I/O. At lhe San Diego

Supercomputer Center, the central computing resource is a CRAY Y-MP8/864

supercomputer with a peak execution rate of 2.67 Gflops, capable of generating up to

2.67E+9 operations/sec * 8 Bytes/operation * 86,400 sec/day

or 1.8 Petabytes per day. In practice, the actual data generation rate is determined by

the workload characteristics. The two major sources of I/O are application disk I/O and

job swapping to support interactive use. At SDSC, the batch load averages 8 GBytes of

executable job images, while the interactive load peaks at 120 simultaneous users. The

batch load is sufficiently large that the idle time on the supercomputer has averaged

1.5% of the wall clock time over the last 6 months. While maximizing CPU utilization

has been an explicit goal at SDSC, this has also increased the total amount of data that

must be manipulated.

Data Flow Analysis

Not all generated data are archived and not all archived data are saved forever. A data

flow analysis is necessary to understand the characteristics of the I/O, including the

amount of data actually generated, the length of time over which the data are accessed,

and the rate at which the data are moved through multiple caching levels. A simple

analysis of the data flow can be used to illustrate the results of changing data access

methods, increasing processing power, or improving network bandwidth. In particular,

the data flow patterns are expected to be different for loosely-coupled user-initiated file

archiving than for automated file servers tightly-coupled to the supercomputer CPU.

PRECEDING PAGE BLANi( ['tOT FILMED

1-145
Solid State Storage Device Cache

The current archival storage system in use at SDSC is DataTree which supports userinitiated file archiving. This system acts as the archival storage file server for the

CRAY supercomputer and is accessed through a 100 Mbits/sec FDDI ring. Data generated

on the CRAY Y-MP8/864 are ultimately stored on 3480 cartridge shelf tape. There are

five levels of I/O buffering or caching, including a 1 GByte Solid State Storage Device,

42 GBytes of CRAY disk local to the supercomputer, 70 GBytes of archive disks, a 1.2

TByte tape robot, and 2 TBytes of manually mounted shelf tape. Table 1 illustrates the

caching hierarchy. As expected, the amount of data moved towards the lowest archival

storage level decreases as the required storage life of the data increases. Data resides on

the SSD for periods on the order of minutes, on CRAY disk for up to two days, on archival

storage disk for up to several weeks, in the tape robot for several months, and finally on

shelf tape for years. The amount of data moved per day between each level varies from

1.5 TBytes/day through the SSD to CRAY disk, 14 GBytes/day through archival storage,

9 GBytes/day through the tape robot, and 2 GBytes/day to shelf tape. The residency time

at any level may be estimaled by dividing the size of the cache by the input I/O rate to the

cache. This closely matches measured data residency times.

The SSD serves both as a data cache for the/root file system and the interactive swap

space and as a data buffer for the large 42 GByte/usr/tmp file system. Caching versus

data buffering depends on the amount of data reuse. The caching of/root to support

interactive users is effective since a hit ratio exceeding 99% can be sustained when the

cache size is set to 68 MBytes. Data caching for the interactive swap space is effective

when about three MBytes of swap space is reserved per user. The actual interactive

swap partition at SDSC is 320 MBytes on the SSD and is restricted to supporting job

sizes less than 8 MBytes. Since the total SSD size is 1 GByte, there is not enough room

to cache the 42 GByte /usr/tmp file system. Instead the /usr/tmp data effectively

stream through the SSD with minimal reuse. The net effect is that the SSD buffers 196

kByte disk data reads for 32 kByte accesses by the application codes. This helps

minimize the amount of time spent waiting on disk seek latencies. Buffering of

/usr/tmp files dominates the I/O rate needed to support swapping of interactive jobs by

a factor of 2.5. Although the SSD transfers data at over 1 GByte/sec, the steady state I/O

rate needed to support streaming 1.5 TBytes of data per day through the SSD _s only 17

MBytes/sec. Replacing with a slower speed communication channel would seriously

degrade interactivity. Swapping jobs at the average transfer rate would require up to

one/half second to load an interactive job into memory. Thus the dominant I/O support

requirements for the SSD are split between providing a large storage area for data

buffering and providing very high-speed access for the interactive job swapping data

subset.

Local CRAY Disk Cache

The CRAY disks also sustain a total amount of I/O of about 1.5 TBytes per day, or an

average of 17 MBytes/sec. Since the total/usr/tmp disk space is only 42 GBytes, the

majority of this I/O is to scratch files which disappear at problem termination. This

can be calculated using the average batch job execution time of one hour and the write

rate to disk being one fourth the read rate. If all the generated data were saved, only

about three hours of CRAY execution data could be stored on local CRAY disk before they

would have to be migrated elsewhere. In practice, the files reside much longer on disk.

Typically 60% of the disk files are up to one day old, and another 25% are up to two days

old. The average residency time is about 30 hours, implying that only one tenth of the

data written to disk survives application code termination. The CRAY disks therefore are

serving as a cache for writing data from the supercomputer.

1-146
Archival Storage Disk Cache

The true long-term data generation rate is governed by how fast data are migrated to

archival storage. On the DataTree archival storage system in use at SDSC, archiving of

files is a user initiated process. Users explicitly choose which files to archive or

retrieve. Typically 14 GBytes/day of data are transferred between the CRAY disks and

the archival storage system of which one third is data written to storage. This amount of

data flow is only 1/7 of that needed to migrate the data that survive on CRAY disk to

archival storage. Thus about 1.4% of the total amount of data written to CRAY disk is

archived. The archival storage disks form an effective cache between long-term storage

on cartridge tape within the tape robot and the CRAY local disks. The hit ratio for

archival storage data being retrieved from the archival storage disks is typically 92%.

Archival Storage Tape Caches

The average data transfer rate needed to support archival storage is 0.16 MBytes/sec.

This should be compared with the observed sustainable archival storage data rates of 0.6

MBytes/sec supported by DataTree running on an Amdahl 5860 across 4.5 MBytes/sec

I/O channels connected to a 12.5 MBytes/sec FDDI backbone network. During periods of

heavy usage, the average transfer rate does approach the peak rate.

Long term archival storage to tape occurs both directly from the CRAY disk for large

files (sizes greater than 200 MBytes) and by automatic data migration from the

archival storage disks. The tape robot serves mainly as a data cache. Data currently

reside about 15 months before migrating to shelf cartridges. Data caching attributes can

be tracked by the fraction of tape mounts done manually. Typically the 1.2 TByte tape

robot processes 85-90% of the tape mounts. The rate at which data are migrated from

the tape robot to shelf tape is roughly 2/3 of the rate at which data are written to the

robot. This ratio may approach one as data in the robot mature.

This data flow analysis demonstrates some interesting attributes of loosely-coupled

user-initiated archival file storage systems.

10% of the generated data is stored temporarily on CRAY local disk, 1.4% of the

generated data is written to archival storage, and 0.6% of the generated data is

eventually transferred to long term shelf tape. Given the need to explicitly save

files, users selectively store a fraction of their output.

The multiple levels of the storage hierarchy serve mainly as caches with more

data flowing into a given cache than flows out to lower caching levels.

The amount of data read at each caching level is substantially higher than the

amount written with the ratio varying from 4:1 for the highest speed cache on

the SSD down to 2:1 for archival tape storage.

The above data flow analysis is typical only of user-initiated archival storage. If an

automated archival storage scheme is used for supporting the CRAY disks, the amount of

data that are archived could grow substantially. This can seriously impact the ability to

adequately handle the I/O if the archival storage hardware environment is operating with

relatively small safety margins. Pertinent safety factors are:

cache residency time versus the latency that a data buffer is amortizing,

1-147
cache residency time of data files on local CRAY disks versus the time needed for

the application to complete, and

sustainable I/O rate versus the peak I/O demand rate.

If any of these factors drop below one, the system will become severely congested and

may even fail. At SDSC, all of these safety margins are relatively small. Due to the

limited amount of CRAY local disk space, the residency time of files on CRAY disk is

comparable to the wall clock time needed to complete an application run for large codes.

The weekly average required I/O rate to access files on the archival storage system is

1/4 of the peak observed sustainable rate. Hourly averages of the required 1/O rate

approach the peak sustainable rate. A usage paradigm shift that increases the I/O load

could seriously stress the archival storage system at SDSC.

File Server Paradigm Shifts

Three possible usage paradigm shifts are being investigated at SDSC, two of which are

related to file servers tightly coupled to the supercomputer CPU power. The first is a

research project funded by the National Science Foundation and DARPA through the

Corporation for National Research Initiatives. Prototypes of tightly coupled applications

distributed across supercomputers connected by a gigabit/sec network are being

developed, including the linkage of an application to the equivalent of a database interface

to archived data. The second is a project to investigate the feasibility of incorporating

the local CRAY disk and the SSD as caches directly controlled by the archival storage

system. The third is the modeling of the impact on the archival storage system of an

upgrade to a 100 Gigaflop/sec supercomputer.

High-speed Remote Access

The CASA Testbed is a collaborative effort between the California Institute of Technology,

the Jet Propulsion Laboratory, the Los Alamos National Laboratory, and the San Diego

Supercomputer Center. One objective is to demonstrate a distributed application

efficiently utilizing two supercomputers while simultaneously using a substantial

fraction of the gigabit/sec wide area network linking the computers. Simultaneously

maximizing bandwidth utilization and CPU utilization requires minimizing the protocol

overhead used for the data transmission[I]. The effective bandwidth for the optimal

application is given by

B/(I+O*B)

where B is the peak bandwidth (bits/sec) and O is the network protocol overhead

measured in seconds of overhead per bit transmitted. For high speed networks, network

protocol overhead becomes a critical limiting parameter. For present CRAY

supercomputers, the network protocol overhead can require the execution power of an

entire CPU to support TCP/IP at 700 Mbits/sec.

Given that a suitable file transport protocol is devised with a small enough protocol

overhead, the issue of latency across wide area networks may be the next limiting factor.

Since the speed of light is finite, data access delays between SDSC and LANL are as great

as disk seek times. Efficient access of remote file systems must then cope with buffering

data in addition to caching data. The amount of data shipped between an application and a

remote database interface to archival storage must be large enough to amortize the data

access delay. Depending on the protocol, the amount of data sent may need to be as large

as

1-148
2L*B

whereL isthe roundtrip latencymeasuredin seconds. Fora LANL/SDSCapplication

running at 800 Mbits/sec,this is still feasible,requiringbufferingon the order of 8

MBytes.

Integrated Local and Archival File Systems

Integrating the local file system into the archival storage file system will substantially

increase the amount of data that must be processed by the archival storage software. As

seen in the SDSC data flow analysis, the amount of data transferred between the

supercomputer and the local disks is more than a factor of 1000 larger than the amount

transferred to archival storage. Efficiently handling this increase in data rates will

require differentiating between "reliable" local file transport and "unreliable"

transport across a local network. By scaling the network protocol overhead needed to

support TCP/IP at 700 Mbits/Sec by the average CRAY local disk bandwidth derived in

the data flow analysis, an estimate can be made of the protocol overhead increase. With

no protocol enhancements, an additional 20% of a single CPU would be needed to support

the archival and local file system integration. This indicates the need for the integrated

system to recognize heterogeneous network environments.

An additional complication is that if all of the generated data stored temporarily on CRAY

disk is automatically archived, the data flow from local CRAY disk to archival storage

could increase by up to a factor of seven. Files written to the scratch /usr/tmp file

system require different backup than files written to permanent home directories. An

integrated local file system and archival storage file system must allow for a nonuniform usage pattern.

CPU Execution Rate Dependence

A possible ameliorating effect is that as supercomputers become faster, it may become

more cost effective to recompute rather than save data. A supercomputer with a

sustained execution rate of.100 Gigaflops is expected to be available by 1995. Assuming

the data storage patterns remain the same, the I/O generated by such a machine can be

estimated by scaling the results of the data flow analysis by the increase in the execution

speed, which is roughly a factor of 3000. The cache sizes and I/O communication rates

then become:

SSD 3 TBytes 50 GBytes/sec

Local disk 126 TBytes 50 GBytes/sec

Archive disk 210 TBytes 450 MBytes/sec

Shelf tape 6000 TBytes 60 MBytes/sec

The archival storage communication rates need to be decreased by a factor of 10 to

become technically feasible. Thus a paradigm shift towards the dynamic regeneration of

simulation output may become inevitable.

Acknowledgement

This work was funded in part by the National Science Foundation under Cooperative

Agreement Number ASC-8414524 and Grant Number ASC-9020416.

1-149
References

1. Moore, Reagan, "Distributing Applications Across Wide Area Networks," General

Atomics report GA-A20074, April 1990.

Table 1

Hierarchical Data Caching Levels

Caching I/O per Data Capacity Utilization Residency

Level Day Rate Period

SSD 1.5 TB 17 MB/s 1GB 85-1 00% minutes

CRAY Disk 1.5 TB 17 MB/s 42 GB 8 5- 90 % days

Archive Disk 5GB 0.05 MB/s 70 GB 98% weeks

Tape Robot 9 GB 0.10 MB/s 1.2 TB 6 8% months

Shelf Tape 2 GB 0.02 MB/s 2 TB 70% years

1-150
File Servers, Networking, and

Supercomputers

Reagan W. Moore

San Diego Supercomputer Center

San Diego, California

SAN DIE(;() SUPERCOMPLgl'I':R CENTER

Archival Storage Systems as

File Servers

• Examine Hierarchical Caching systems

• Capacity requirements

• I/O requirements

• Based on Usage at SDSC

• Archiving supercomputer generated data

SAN DIEGO SUPERCOMPUTER CENTER

1-151
File System Usage

Paradigms

• Loosely-coupled to CPU

• User initiated file transfers to archival

storage

• Tightly-coupled to CPU

• NFS access

• Integrated local and archival file systems

SAN DIEGO SUPEkCOMPUTER CENTER

SDSC Archival Storage

Environment

• Data Generated by CRAY Y-MP8/864

Supercomputer

• FDDI 100 Mbits/sec backbone

• DataTree Archival Storage System on an

Amdahi 5860

SAN DII._(;o SUPER('OMPI'TER ('ENTER

1-152
Five Levels of Data Caching

• Solid State Storage Device (SSD)

• 1 GB, 1.2 GB/s access from memory

• CRAY local disk

• 42 GB, 10 MB/s access per disk

• Archive storage disk

• 70 GB, 0.6 MB/s access across FDDI

• STK tape robot

• 1.2 TB, 0.6 MB/s access across FDDI

• Shelf cartridge tape

• 2 TB, 0.6 MB/s access across FDDI

SAN DIEGO SUPERCOMPUTER CENTER

SDSC Workload Characteristics

• Application Disk I/O

-Generated by an average batch load of 8

GBs of executable jobs

• Job Swapping

• Generated by up to 120 interactive users

• User-initiated File Archiving

• Partial archiving of supercomputer data

SAN DIE(;O SUPERCOMPUTER CENTER

1-153
Data Flow Analysis

• Track Data Through the Multiple Caches

• Cache utilization

• Hit rate

• I/O throughput

• Fraction of peak rate

• File residency time

# Identify Caching versus Data Buffering

SAN DIEGO SUPERCOMPUTER CENTER

SDSC Data Flow

Cache Level

SSD

CRAY disk

"1

Archive disk

Tape robot

=

Shelf tape

i

Capacity (GB) Utilization

42

7O

1200

2000

85%

90%

98%

68%

70%

SAN DIEGO SUPERCOMPUTER CENTER
SDSC Data Flow

Cache Level

SSD

CRAY disk

Archive disk

Tape robot

Shelf tape

SAN DIEGO SUPERCOMPUI"ER t_ENTER

Residency

Time

(seconds)

30 hours

4 weeks

15 months

5 years

Fraction saved of total

I/O written from SSD

100%

10%

1.4%

1.4%

0.6%

SDSC Data Flow

Cache

Level

I/O per Day

(GBytes)

Data Rate

(MBytes/sec)

SSD 15OO 17

CRAY disk 15OO 17

Archive disk 5 0.05

Tape robot 9 0.10

Shelf tape

SAN DIEGO SUPERCOMPUTER CENTER

2 0.02

1-155
Data Caching Versus Data Buffering

SSD Cache Used for Both

•/root file system and Interactive swap

space are cached

• Hit rate for accesses is 99%

•/usr/tmp file system is buffered

• Hit rate for accesses is 75-85%

SAN DIE(;O SUPERCOMPU'TER CENTER

File Server Safety Factors

• Cache Residency Time versus Latency

Amortization Time

• Cache Residency Time versus File Usage

Time

• Sustainable I/O Rate versus Peak I/O

Demand Rate

S_SUeERCoMPUTERC_:_ER

1-156
File Server Paradigm Shifts

• Changes in Funtionality May Require

Usage Paradigm Shift

• Highspeed remote access

• Integration of local and archival file

systems

• Very highspeed supercomputers

SAN DIEGO SUPERCOMPUTER CENTER

CASA Gigabit/sec Testbed

• Collaboration between CalTech, JPL,

LANL, SDSC

• Demonstrate Tightly Coupled Distributed

Applications Linked by Gigabit/sec Wide

Area Network

• Remote access of archived data through

database interface

SAN DIEGO SUPERCOMPU [ER CENTER

1-157
CASA GIGABIT WAN

Local Carrier

JPL

PoP

Local Carrier

Long Distance Los Alamos

_ Carrier

,_ Point of PmNnce

Network Protocol Overhead Impact

• Simultaneous Optimization of CPU and

Bandwidth Utilization

• Effective bandwidth is given by

-B/(I+O*B)

• B = bandwidth (bits/second)

• O = protocol overhead (seconds/bit

transmitted)

SAN DIEGO SUPERCOMPUTER CENTER

1-158
Protocol Support Limitations

• TCP/IP Protocol Can Require Execution

Power of Entire CPU of Y-MP8/864 for

700 Mbits/sec Bandwidth

• Effective Bandwidth Reduced 45%

SAN DIEGO SUPERCOMPUTER CENTER

Wide Area Network Latency Can

Require Data Buffering in Addition to

Data Caching

• Finite Speed of Light Creates Latency

Between SDSC and LANL Comparable to

Disk Seek Latencies

• Amortize Latency by Shipping Large

Files

• Size = 2 L * B

• L = Round-trip latency (seconds)

• For 800 MBits/sec network, ship 8 MB

files

SAN DIEGO sUPERCOMPUTER CENTER

1-159
Integration of Local and Archival File

Systems

Local CRAY Disk Supports 1000 Times

as Much Data Transfers as Archival

Storage at SDSC

To Minimize Protocol Overhead

• Distinguish between

• "Reliable" local file transport

• "Unreliable" local network transport

• Otherwise expect overhead to increase

2O%

SAN DIEGO SUPERCOMPUTER CENTER

Integration of Local and Archival File

Systems

• User-initiated File Archival Storage

Results In

• 1/7 of the data being archived

• Automatic Migration of Local Files

• Allow non-uniform file migration across

different file systems

•/root versus/usr/tmp

SAN DIEGO SUPERCOMPUTER CENTER

1-160
Supercomputer I/0 Scaling

• For a 100 Gflops/sec Supercomputer

• Scale I/O by ratio of CPU speeds

• Expect 3000 times as much I/O

• Massive data generation may require

dynamic regeneration of data rather than

storage

SAN DIEGO SUPERCOMPUTER CENTER

CPU Execution Scaling

Cache Level

SSD

CRAY disk

Archive disk

Tape robot

Shelf tape

SAN DIEGO SUPERCOMPUTER CENTER

Capacity (TB)

3

126

210

6000

12000

Data Rate (MB/s)

50,000

50,000

450

60

6O

1-161
File Server Paradigm Shifts

• Data Storage Requirements Will Be

Increased by

• Integration of Local and Archival

Systems

• Higher Speed Supercomputers

• Possible Shifts

• Local regeneration of data

• Remote File Access

SAN DIEGO SUPERCOMPUTER CENTER

1-162
N93-1 138

MASS STORAGE SYSTEM

EXPERIENCES AND FUTURE NEEDS

AT

THE NATIONAL CENTER FOR ATMOSPHERIC

RESEARCH

Summary of the Presentation to the Conference on

Mass Storage Systems and Technologies for

Space and Earth Science Applications

July 23-25, 1991

by

Bernard T. O'Lear

Manager, Systems Programming

Scientific Computing Division

National Center for Atmospheric Research

1-163
3/5/91

This is a summary of the presentation given at the Conference on Mass Storage

Systems and Technologies for Space and Earth Science Applications. The presentation was compiled at the National Center for Atmospheric Research (NCAR),

Boulder, Colorado. NCAR is operated by the University Corporation for

Atmospheric Research and is sponsored by the National Science Foundation. Any

opinions, findings, conclusions, or recommendations expressed in this paper are

those of the author and do not necessarily reflect the views of the National Science

Foundation.

1-164 --
This presentation is designed to

relate some of the experiences of the

Scientific Computing Division at NCAR

dealing with the "data problem." A brief

history and a development of some basic

Mass Storage System (MSS) principles are

given. An attempt is made to show how

these principles apply to the integration

of various components into NCAR's MSS.

There is discussion of future MSS needs

for future computing environments.

NCAR provides supercomputing and

data processing for atmospheric, oceanic

and related sciences. This service is

provided for university scientists and for

scientists located at NCAR. There is a total

of about 1200 users.

The data problem for this

community can briefly be summarized as

follows; Historical atmospheric data is

archived, programs are saved and the data

which model the atmosphere, oceans and

sun are saved. The NCAR storage

experience is based upon current

supercomputing megaflop rates which

produce a number of terabytes archived

on a yearly basis. There is a history of

data growth and file growth. The NCAR

data storage experience has been as

follows; There are about 500 bytes of

information archived for each megaflop

of computing. When NCAR had an XMP/48, the archive rate for the utilized

megaflop compute rate was 3 terabytes

per year. The installation of a Y-MP8/864

increased the archival rate to 6 terabytes

per year. Forecasting future computing

configurations and atmospheric models

being planned we are now approximating

a 30-50 terabyte archive per year rate by

the year 1993 or 1994.

Data has been saved in many forms

over NCAR's existence and then migrated

to machine-readable media. Some of the

data has come from handwritten logs,

from punch cards, half-inch tape. All of

this has been collected and is now

archived on IBM 3480 cartridge tape. One

of the basic principles for archiving this

data is to identify certain classes of data.

Archive data is kept forever. Long-term

data is kept for 10 to 15 years. Near-term

data is kept for 1 month to 1 year and a

category called scratch data is killed after

1 month and cannot be recovered

automatically by the system.

One of the other basic principles

that has been identified is that dataset

sizes continue to grow as a function of

supercomputing sizing. The amount of

data that can be saved is bound in storage

by media capacities. That is, these criteria

are established for determining which

data will be saved and for how long

because there is not an infinite media

capacity at this time. Our experience has

shown that every 10 to 15 years the data

in the MSS will need to be migrated to a

new media base because of changing

systems and obsolescence of existing

media. Usually the media or the drives

cannot be purchased anymore. This

migration takes place not because the data

is bad on the media, but because the drives

will not be available.

Another problem is that a number

of companies have provided the capability

for this massive storage, but the small

companies tend to disappear within five

years. The drive components that have

been furnished for mass data storage

disappear in five to eight years no matter

what company they come from.

The next basic principle is that the

migration of the mass storage system data

to a new media base, which is now several

ten's of terabytes, is not a trivial

operation. The migration does not take

place in a short amount of time. For

instance, one-time migrations can run for

long periods of time, necessarily years to

move terabytes data. It is very difficult to

guarantee that the data is migrated

absolutely without reading it back, which

is time consuming. These migrations are

very costly and in my opinion shouldn't

be done. We have developed the concept

of "DATA OOZE," and we prefer this

technique over migration right now. The

way DATA OOZE works is that it is a

continuous movement of data within the

system. The data is moving across the

1-165
storage hierarchy and across the

changing media types under the control

of the MSS. The migration path for this

data in the hierarchy can be from

memory to solid state disk to high speed

disk to disk arrays or farms, and from

there out to some kind of tape. Later on as

new data storage media become available,

the data is migrated onto these media in

real time, since every day some amount of

the data is migrated as it is being used.

Our conclusions from these

experiences have been that new

components and media types are

integrated according to the following

rules; Use standard components. The

standards may be real or de facto and

apply in the areas of channels, interfaces,

operating systems, media, etc. We look for

media that is easy to obtain and is cost

effective. We look for the long-term

viability of the vendor and multiple

sources for the many system components.

In the area of mass storage system

integration we look at access speeds, ease

of expandability, heterogeneous host

access, maintenance costs, media costs and

systems costs.

There are a number of future

growth issues for the NCAR MSS. The

Scientific Computing Division (SCD)

continues to develop future configuration

scenarios. These scenarios try to

anticipate the functional requirements

we anticipate providing for our scientific

community. There are three key

components we need to address: network

services and access, the large scale

computing (Big Iron), and the data

archives. Of course, these all play within

the context of distributed computing.

The near-term issues for the NCAR

MSS focus on some immediate upgrades

which will deal with the MSS growth for a

couple of years. The entire archive will

be migrated onto double density 3490 and

3490-compatible media. The mid-90s to

late 90s became more interesting because

of the expanding interest in archiving

vast data collections.

The issues of future growth will be

centered in three areas of ongoing

development: the various MSS software

packages, the data storage components

and the networks.

The questions then become how all

of these components get assembled and

which ones do we plan to use. Will SCD be

able to construct on effective peta-byte

MSS by the end of the decade? Which of

our basic principles can we apply to

insure that such a system can be built?

###

1-166
f

Mass Storage System

Experiences and Future Needs

at

The National Center for Atmospheric Research

Conference on Ma_ Storage Systems

and Technologies for

Space and Earth Science Applications

July 23-25, 1991

Bernard T. O'Lear

Manager, Systems Programming

Scientific Computing Division

National Center for Atmospheric Research

| NCAR Sctent'_ic

f

The following presentation was compiled at the

National Center for Atmospheric Research

Boulder, Colorado

- The National Center for Atmospheric Research is operated by the

University Corporation for Atmospheric Research and is sponsored by the

National Science Foundation.

• Any opinions, findings, conclusions, or recommendations expressed

In this talk are those of the author(s) and do not necessarily reflect the views

of the National Science Foundation.

| NCAR Scler_ C_ O_s/on

1-167
Introduction

The experiences of a scientific center dealing with

"The Data Problem"

• Brief history

• The current computing environment

• Development of some basic principles

• How the principles apply

• Future needs for future computing environments

| NCAR Scientific Co¢'rlput_ng Division

J

=

History

NCAR provides supercomputlng and data processing for atmospheric,

oceanic, and related sciences:

• At unlverslflos

• At NCAR

- Totals about 1200 users

The data problem for this community

• Save and archive historical atmospheric data

• Save programs and data which model the atmosphere, oceans, and sun

1-168
f

The NCAR Storage Experience

• 500 Bytes per million flop

• Archival rate for model output

- 4 TBytes/year with X-MP/48

- 8 TBytes/year with Y-MPS/864

- 40 TBytes for climate simulation

r_| NCAR Scientific Con'out no D vision J

_ II4III-Det= (;k.m_

lll4-1J_l

147-t4.fl_

M

!

t M

I

_..Li;;;: r'l _,_l.t. c_m. o.,= J

1-169
f

NCaJt MU-I_b

l_U-;J91

_,rw__ | NCAI=I fx_Iontlfle Comp_ing Dlvl,olo_

_ _.,;;"_;,_,-;_.. o., J

NCAR Mass Storage Systems

(MSS)

Usage Data ]

101,700 tape cartridges in use

Over 18.5 Tbytes of data stored

Over 710,000 flies

Average file length 26.2 MB

Fast Path ]

S 2 minute delivery

_,_ i _. _._...o_0_....._..__

I-'I_ _,0=,,_. co,,,_,_,,., o.. J

1-170
f

History

(Continued)

Data saved in many forms -- then migrated to machine readable media:

• Handwritten logs ...... > Punched cards

• Punched cards ...... > One-half inch tape

• One-half inch tape ...... • AMPEX TBM tape

• AMPEX TBM tape ...... • IBM 3480 tape

• IBM 3480 tape ..... • IBM 3490-E tape

• IBM 3490-E tape ..... • ? ? ?

_ __.. | NCAR Scie_ifk: ComputinQ OI_sk_

Basic Principles

• Identification of data classes:

• Archive data = keep forever

• Long-term data = keep 10-15 years

• Near-term data = keep I month to I year

• Scratch data = kill after I month

[] _,_. _,.,_.. _.. J

1-171
Basic Principles

(Continued)

• Dataset sizes continue to grow as a function of supercomputer sizing

• Dataset sizes are constrained in Storage by media capacities

• Every ten to fifteen years, the data In the MSS will need to be migrated

to a new media base

| NCAR Sciontiflc Computing Otvt_on J

Basic Principles

(Continued)

Migration:

• Not because the data is bad on the media...

• But because the drives will not be there

- Haft life of a start-up company = 5 years

- Haft life of drive electronics = 5-8 years

J

1-172
f

Basic Principles

(Continued)

The migration of MSS contents (" n" tera-bytes) to new media

is not a trivial operation

One-time migrations:

• Run for long periods of time (years)

• Are difficult to guarantee

• Are costly

• Shouldn't be done

1 NCAR ScientfflcC ufin Olv_$1on

_ [_---_J sup_=pu., • coe_icJ,on. • Da.

Basic Principles

(Continued)

4

Data OOZE preferred over migration

Data OOZE is a continuous movement of data within the system:

• Data movement across:

- The storage hierarchy

- The changing media types

r'-_ _,.,_,.0. _..._.,. _..

J

1-173
Memory

State

Disk

High-Speed Disk

Disk Arrays or Farms

4480_ __tape

Optical Optical [ Optical I Other

Disk Disk [ Disk I Distributed

Worm MO I ROM [ _ Systems

_.. _,_ _-_ _T'_(EXABYTE)

/ NCAR Scientific Computlr_ Division

EEl _;.;_;:_;__-__;:_.

CONCLUSIONS

New components and media types are Integrated according to

these rules:

• Standards (real or de facto)

- For channels and Interfaces (IBM, IPI, HIPPI, SCSI)

- For media

• Long-term viability of vendor

• Multiple source availability for media (drives?)

J

1-174
MSSIntegration

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• Multiple heterogeneous host access

• Maintenance costs

• Media costs

• System cost

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FUTURE GROWTH

ISSUES

IN THE

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1-175
Functional Diagram

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1-176
FY93-95 Functional Diagram

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Archives Iron and Access

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2. Automatic double density migration takes place for shelf archive

3. Hope is STK furnishes double density for drives on ACS In

< 6 months.

| NCAR Sckmtlflc C Division

J

1-177
NCAR MSS

The Issues of Future Growth are dependent upon:

1. Future MSS Software

a. Distributed MSS

b. Large archives (Peta-Byte)

2. Future Data Storage

a. The media

b. The drives

c. The robotics

3. The Network and Channels

a. HIPPI

b. Fibre channel standards

c. fabric (switch)

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• UNITREE (DISCOS)

• Infinite Storage Architecture (EPOCH)

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• EMASS (E-SYSTEMS)

• NAStore (NASA, Ames)

• NETARC and AWBUS (CDC)

• swIFr (IBM)

DataMe_,sh (Hewlett Packard)

M (DS) ':NASA Goddard

b. Peta-Byte Archives

• How do we build them?

_,_ | NCAR Sclent_c C O_l__uting. Divilion J

1-178
2. Future Data Storage

a. THE MEDIA

• The 3M National Media Laboratory (Media Database)

• Government funds and goals

• Private sector partidpation

• Standards being developed

b. THE DRIVES

• Being developed for the media

• 10-year life span

• Attachable to various robotics

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• ODETICS

• EXABYTE and others

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• Security

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c. Fabric Switch

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1-181

N93-13139

The Long HoI_ Storing Data at the National Archives

Kenneth Thibodeau, Ph.D.

Director, Center for Electronic Records

National Archives and Records Administration

The National Archives is, in many respects, in a unique position. For example, I find people

from other organizations describing an archival medium as one which wiU last for three to

five years. At the National Archives, we deal with the centuries, not years. From our

perspective, there is no archival medium for data storage, and we do not expect there will ever

be one. Predicting the long-term future of information technology, beyond a mere five or ten

years, approaches the occult arts. But one prediction is probably safe. It is that the technology

will continue to change, at least until analysts start talking about the post-lnformation age. If

we did have a medium which lasted a hundred years or longer, we probably would not have a

device capable of reading it.

The issue of obsolescence, as opposed to media stability, is more complex and more costly. It is

especially complex at the National Archives because of two other aspects of our peculiar

position. The first aspect is that we deal with incoherent data. The second is that we are

charged with satisfying unknown and unknowable requirements.

The data is incoherent because it comes from a wide range of independent sources; it covers

unrelated subjects; and it is organized and encoded in ways that not only do we not control but

olden we do not know until we receive the data.

The sources are potentially any operation of the Federal Government, or its contractors. The

National Archives has been in the business of collecting digital data for two decades. The way

we get it is through our authority over all federal records. Under the Federal Records Act, no

agency of the Federal Government can destroy or alienate any Federal record without

authorization from the Archivist of the United States, who is the head of the National

Archives and Records Administration. Simplistically, the way it works is that agencies tell us

what records they have, and we tell them which ones they can destroy when they no longer need

them, and which ones must be preserved for posterity. (The definition of Federal record in the

law explicitly includes machine-readable files.)

Since 1972, we have reached agreements with agencies that provide for them to transfer to us,

and for us to preserve, data from 600 data collections. 573 of these are still active. From these

agreements, we have received over 10,000 data files. The rate of transfer has increased

dramatically in the last two years: In fiscal year 1988, the National Archives received 167 data

files. So we are currently operating at eight times the volume of new files we had years ago, and

we expect at least to double next year.

Those numbers are very encouraging, but the overall picture is rather bleak. If we look at all of

the data which was scheduled to arrive in the last twenty years, from those 600 data

collections, we have received less than 7% of the transfers which should have been made. We

recently completed development of a system to generate dunning letters to agencies who fail to

transfer data as scheduled, and to track each case to completion. But this system creates

additional problems. If I implement it as planned, on a government wide basis, we would need

to increase our capability to handle new files, not by doubling current capacity, but by

increasing it more than six times. And to handle the backlog of data which should have come

in before now, I would need at least 10 times our current capacity.

The past gives us pause. But the future is a brave new world. At least it requires a degree of

bravura Just to glance in that direction. We have underway a study which is looking beyond the

600 data collections we have decided to preserve to see what else is out there. It is a study of

major federal databases being conducted by the National Academy of Public Administration

PRECEDING PAGE BLANK NOT FILMED

1-183
(NAPA).This study has someinterestingexclusions. First of all, wetold NAPAnot to bother

with systemsusedfor generichousekeepingfunctions, suchaspersonnel,payroll, procurement

and supply,becausethereis little likelihoodthat wewouldhaveany interestin preservingdata

fromsucha system.Secondly,wetoldthemnotto lookat big science,becausethat is sucha

largeand complexareathat it deservesseparateattention. (Wehopeto engagein a projectwith

the NationalAcademyof Scienceson the preservationof scientific data.] Thirdly, wetold

NAPAnotto worry toomuch about databasesonPCs,simply becausetheywouldneverfinish

the projectif they triedto find all the interestingdatabasessitting on desktops.With those

limitations, NAPAhas identified over 10,000databases.

Obviously,that is fartoobig a numberevenfor us to think about. SowegaveNAPAa setof

criteria for culling from the total inventorya subsetof thosedatabaseswith somelikelihood

that the NationalArchiveswouldbeinterestedin preservingthem. Wethought wemight wind

upwith a llst ofthe 500mostimportant databasesin the FederalGovernment,from an

archivalperspective.That list wouldposequite a challenge for us, because it could practically

double the total number of data collections generating data that we want to preserve. The

subset of 500 currently has about 900 members.

The next phase of this study is to solicit advice from subject area experts about what data we

should try to preserve. NAPA has organized five working groups, with a total of 32 experts in a

variety of fields. We are bringing these people together at the end of July for a four day meeting

where they will try to develop some common opinions on the long term value of the data.

Which brings me back to the basic point here: what we are dealing with is incoherent data. It

concerns practically any area in which the United States Government is involved, which is

practically anything. The data we already have ranges from data about tektites on the ocean

floor to military operations in time of war. It includes census data on population and the

economy, data on Japanese-American internees in World War II, detailed data on air traffic

and on stock and bond transactions, and on many, many other subjects. The variety of

subjects covered is also increasing.

The data is extremely diverse in content, but content is Often the only thing we know about the

data until it comes in. We know how many transfers are due, but most oRen we do not know

what the volume of data in a transfer will be, or how it will be organized, even at the physical

file level. For example, the files which came in during the first six months of this fiscal year

ranged in size from 6 K to 1.4 gigabytes. The number of files in a transfer has ranged from one

to 400, and we expect some transfers in the next few years will contain thousands of files.

One thing we do know about the data before it arrives is its logical structure: everything we

receive is in fiat file format, because we require it to come in that form. however, we realize

that this requirement is unreasonable and unrealistic in many cases. We are working to

expand the range of formats we will accept to include relational tables. We expect to change our

regulation to that effect by the end of this year. We know that, when we do that, it will be only

one of many steps we will have to take in a Journey with no foreseeable end.

That is a brief overview of one aspect of the unique situation of the National Archives. The

second aspect is that we are charged with satisfying unknown and unknowable requirements.

NARA's mission to preserve and provide access to records with enduring value makes NARA, in

effect, the agent of generations yet unborn. What differentiates this agency from other parts of

the government is the unique responsibility NARA has to serve the information needs of the

distant future. This responsibility is fundamental to the very essence of the National Archives

as keeper of the Nation's memory.

NARA's responsibility to the future places us in a perpetual quandary: we must devote

ourselves to serving needs which we cannot know. We cannot know the questions the future

will ask of its past, nor how future researchers will go about answering these questions. We

must assume, however, that the information technology which will be available in the future --

1-184

=
- even in the very near future --- will be more powerful and more flexible than what is available

today. Information processing problems which today are difficult and costly, if not impossible

to solve will become as simple as getting a computer to print out narrative in paragraph form.

(A short 20 years ago that was beyond state of the art.)

Along with the technology, analytic tools will continue to improve: there will be further

developments as powerful as the mathematics of chaos which will help researchers to

understand things which today appear to defy reason. We can also assume that events will

happen in the future, which will be as threatening as the depletion of atmospheric ozone, or as

exciting as Operation Desert Storm, or as commonplace as the passing of generations, which

will make future users want to go back to reexamine the records of the past.

3
EVENING SESSION

(8:30 p.m.)

DR. HARIHARAN: Ladies and gentlemen, it is my pleasure again to introduce Dr.

Mallinson, who will be giving us a talk about his reminiscences in the field of magnetic

recording over the last 40 years.

(Laughter)

DR. HARIHARAN: Dr. Mallinson has an M.A. Degree in Natural Philosophy in Physics

from University College in Oxford, England. And he Joined the Ampex Company in

Harrisburg, Pennsylvania in 1954 to work on the theory and design of magnetic lodging

elements.

In 1962, he Joined Ampex Corporation in Redwood City, California, where he held

many positions concerned with the understanding and development of magnetic recording

systems. From 1976 to 1978, as Manager of Hybrid Magnetic Recording in the Data Systems

Division, he was concerned with the initial design of the 750 MBS digital recorder.

From 1978 to 1984, he supervised the Magnetic Recording Technology Department

Multidisciplinary Group, working in magnetic recording theory, high density head

fabrication, coding and communication theory, and the exploration of advanced concepts in

various areas of recording. In 1984, he was appointed as the Founding Director of the Center

for Magnetic Recording Research at the University of California, San Diego. Since 1990, he has

been the President of Mallinson Magnetics, Inc. He has published over 60 papers on a wide

variety of topics in magnetic recording.

Dr. Mallinson was an IEEE Magnetic Society Distinguished Lecturer in 1983. In 1984,

he was awarded the Alexander M. Poniatoff award, named after the founder of Ampex

Corporation, an award for leadership in the theory and practice of magnetic recording. Dr.

Mallinson?

(Applause)

1"186
BANQUET PRESENTATION

Professor John C. Mallinson

DR MALLINSON: Thank you, Hari I've given a great deal of thought to what I should say

to you this evening. Options ranged from telling you a number of risque Jokes; but I realize that

I have, in fact, been invited to give some reminiscences on--it's not a 40-year career; I'm not

that old --

(Laughter)

DR. MALLINSON: But I have had a career since 1962 in magnetic recording. The most

important of those years, I think, were the years at the Ampex Corporation; I was there for 24

years.

So, basically, what I'm going to talk about is some reflections on 24 years at Ampex.

First of all, I want to tell you that I think in the field of magnetic recording research and

development, Ampex Corporation has very, very few equals. I won't list for you all the things

that Ampex has developed; but most prominent amongst them is surely the invention of video

tape recording.

oRiGiNAL pAGE

BLACK AND wH!TE pHO'TOGRA'P_

1-187
DR.MALLINSON:Thereis a picture ofAlexM. Poniatoff,the founderofAmpex,

standingbesidea videorecorder.AlexM. Poniatoffhired mein 1962toJoin theAmpex

Corporation,andwehit it offtogetheralmostimmediatelybecauseI wasa pilot in the British

RoyalAir Forceand still am a pilot, AlexM. Poniatoffwasa pilot in the RussianAir Forcein 1919.

And I will recountfor you onestory ofAlex M. Ponlatoff, and you should Just think

about this story while looking at Poniatoff when he is 76 years of age there.

In 1919, Alex M. Poniatoffwas a Captain in the Russian Air Force. He was flying a

wooden six-engined aircraft; I'm not sure what it was. Let's call it a Sigorsky; and they were

flying it off some lake somewhere in Russia.

And one day, he went out tO the lake and noticed that the red flag was flying; and he

knew, as a good Captain in the Russian Air Force, that that meant that the commanding officer

had decided that today the water was too rough for flying.

But Alex M. Poniatoff thought otherwise, as a young 'Turk, " as they say, in the Russian

Air Force. He gathered up his copilot and his engineer, and they commanded someone to row

them out to the flying boat; and they fired up the engines, turned it into the wind, and

commenced the take-off run.

But I am not telling this story anywhere near as funny as he told the story; but long

before the thing even got on the stack, before it even started showing any signs of becoming

airborne, this wooden flying boat disintegrated. It broke up.

And shortly thereafter, he found himself in this icy cold water, calling out for his

copilot and his engineer; and they all swam to each other and must have thought: What the hell

are we going to do now?

And they noticed another small boat; this time it was a motor boat coming out, with

their commanding officer in it. And he told me this hilarious story about what the

commanding officer had to say about him; it was the end of his career flying the flying boats in

the Russian Air Force.

So, that is Alex M. Poniatoff standing in front of the first Ampex video recorder in

1956. The video recorder is that unit; that unit weighed 1,100 pounds. And behind him is this

cabinet which had 275 vacuum tubes in it; that was the electronics of the thing.

A reel of tape on that machine was 12 inches in diameter, 2 inch tape, and it recorded

black and white television--NTSC television--for one hour. That was in 1956.

Before 1970, people had decided to use this video recorder for recording digital

information; and such a reel of tape held 30 times 109 bits of information. I'll try and stick

with bits all the time. Video people talk bits; computer people call big bits bytes.

They had 30 times 109, 30 gigabytes, of data on it. And Ampex at that time, as was

mentioned in the Session today, started selling a system called the Terabit Memory, the 1012

bit memory. A 1012 bit memory had no less than 32 of those units.

And basically, what I'm going to talk about-- after some remarks--is how the evolution

of recording since, say, 1960 to 1990. over the last 30 years, has resulted in much more compact

ways of recording 1012 bits of information.

At that time at Ampex, when these terabit systems were being made, with their 32

transports and their four Philco computers controlling them, we used to laugh at the idea of a

terabit in a drawer; it was a joke. Well, a terabit in a drawer is now something which is

available to everyone. I will show you a foil of it later on.

1-188
Ratherthan showfoils all the time,which wouldjust makeit into a technicaltalk, I

thought I wouldJust plain talk to youaboutoneof my majorreflectionsatAmpex;andthat is

how it is that everytwo or three,perhapseveryfive,yearsit wasperceived,though,that there

was someimportant threat to the dominanceofmagneticrecording.And I'm afraid to tell you

that that still goeson today,this notionthat thereis somethingaroundthat is goingto

displacemagneticrecording.

After30or 40 yearsof it, I very,verymuchdoubt it, but I amgettingaheadofmyself.

Thefirst thing that camealongin the early 1960s,probablybecausesomany of the

Ampexengineerswereinvolvedin televisionand televisionrevolvesaroundcathode ray tubes-

-TV tubes--the notion came up that an electron beam recorder would be the best thing. It would

be the answer to the maiden's prayer.

And Ampex, in the early 1960s, made electron beam recorders. The electron beam

recorders recorded on photographic film that was specially made for us by Kodak; the track

following servo was done by wobbling the electron beam, the dithering method of track

following and observing scintillations of the scintillator coating on the back of the

photographic film.

It recorded 100 megahertz analog bandwidth, which supported two 30 megabit per

second channels. It was considered to be something wonderful in 1960 because the terabit

memory was only about 5 megabits per second per channel, and this electron beam recorder

had two 30 megabit per second channels.

What was wrong with the electron beam recorder like that? First of all, everything had

to be done in a vacuum. Electron beams don't go too far in the air.

Secondly, it used photographic film, which had to be taken out of the vacuum and

developed and put back in the vacuum to play back.

And thirdly, it was an enormously large machine. The electron column on it looked

like a regular electron microscope. It was about 8 feet tall; and in fact, the customer for the

electron beam recorder, the U.S. Air Force, found it necessary to increase the size of the cargo

hatch of the C-130 at the time. It just wouldn't go in.

So, that was one of the things that had us all abuzz. Electron beam recording was going

to solve all the problems. In retrospect, it's hard to know why people were so naive to think

such a thing as that.

Shortly thereafter, a company was started in Boston; one of the principals, Dennis

Speliotis, is here. It was called Macrobit. Macrobit had a similar notion that they were going to

use electron beams to record on silicon wafers. Single crystal silicon had more or less just

become available in the mid-1960s, and their notion was basically to lay out

photolithographically little capacitors on a silicon wafer--tell me if I'm wrong, Dennis.

They were going to lay out little capacitors on a one-lnch square, or maybe a one-and-ahalf inch square, single silicon wafer; and it would have a capacity of about 10 megabits. And

that one failed, I believe, because 10 megabits is a ridiculously small capacity.

At least at Ampex, it was realized that since Ampex's principal business was recording

massive amounts of analog signals or data, 10 megabits was Just too small a module to be of

interest.

So, electron beam recording on silicon disappeared.

1-189
Therewasalso a slight cautionary taleaboutthat mlcroblt memoryin that its capacity

did not exactlymatchthe then-IBMdisk drives. TheIBMdiskdrivesof the periodwere3330s;

and the Macrobitmemoryhad somethinglike 7percentmorecapacitythan a single3330,

which in somesphereswas its deathknell becauseit's onething to saythat wewill havean

excesscapacityin somememorydevice;andif wedon'tneedto useall of that, wewill Justfill it

in with garbage--youknow,we'llJustaddnoise,random l's andO's.

It is onething to saythat; it is altogetheranotherthing to find somesoftwareengineers

or somepeoplewhowill dothat. So,there'sanotherlessonto belearned.

Thetwomain reasonsfor electronbeamrecordingwere,of course,that youcould dothe

recordingwithout touchingthe medium. Touchingthemediumor not touchingthemedium

wasconsideredto bean extremelyimportantfact;and that, in turn, ledto the ideathat there

shouldbeopticalrecordersof onekind or another.

I hateto think howmuch moneytheAmpexCorporationdumpedinto optical

recording. Magneto-opticalrecording,which hasbeentalkedabout this morningby the man

from Alphatronix, is in its third--what's the right word?--lifeat the moment.

Originally,in the 1960s,the first life--the first period--ofmagneto-opticalrecording

wasbeingdoneonmanganesebismuth;that wasthematerial. Youhadto put in an awful lot of

poweronthemanganesebismuthto heatit up to its Curietemperatureof 400° or 3500

centigrade.

And then, the materialbasicallyfailedbecause,afterrepeatedcyclesto that high

temperature,it changedphase;and theCurietemperaturechanged.It wasunstablematerial;it

wouldnot stand indefiniterecyclingfrom roomtemperaturesup to 4000 centigrade.

Now, the second phase of magneto-optic recording led by Big Blue, was of course the

Europium oxide run, which had terrible trouble that its compensation temperature was at

liquid nitrogen temperatures. It failed. And the current one, which is iron cobalt--some rare

earth--usually terbium--may or may not make it. Mr. Freese this morning said it would make

it in a "niche" market; and I think that's about the right way to think about it.

What was the perception at Ampex of magneto-optic recording? Why, it was that Ampex

should go ahead and make a magneto-optic tape recorder. And in 1966, there were shipped to

the U.S. Navy no less than five magneto-optic tape recorders.

These tape recorders had 2 inch wide tape in them; the recording was transverse scan,

just like the quad video machines. The transverse scan was done with a rotating polygonal

mirror that was going round at 14,400 rpm, just the same speed as the quad drums. They were

writing on a hard magnetic film with a permalloy overlayer and the readout scheme supported

a data rate of 10 megabits per second.

We should have been smarter at that time to realize that this was in the mid- 1960s; 10

megabits per second was already much slower than magnetic recorders were going in the mid1960s.

But nevertheless, the hope persists in the human animal that there will be some other

technology that will get you out of your perceived present problems.

The magneto-optic recorder was expensive; and I forgot to mention that, at that time in

optical recording,there were no gallium arsenide solid-state diode lasersaround. The-lasers

were all helium-neon gas lasers; and the gas lasers in this magneto-optic recorders shipped to

the Navy were fully 24 inches long--helium-neon gas lasers. So, that failed.

1-190
I would saythat basicallythe principal reason it failed was that it had material

problems; and in particular, it had material problems where it was not possible to get more

than I0 megabits per second data rate through it.

And that, I believe, is a persistent problem that is related with magneto-optic recording

throughout all of its history including today. It is hard to get high data rates. So, it is a

question to do with signal-to-noise ratio, which we don't have to go into.

50 megabits per second today is considered a high data rate for magneto-optic recording

of any kind.

At the same time, or shortly after we realized that the magneto-optic recorder was not

quite the right way to go, there was work undertaken in WORM, laser melting or oblating of

some material like tantalum. It was very rapidly discovered that --

You know, the initial discovery phase of all of these endeavors is very exciting and goes

very rapidly; and it is only later that we realize that you haven't got anything worthwhile.

In the case of the laser oblating, the pure WORM optical disk, it was very rapidly

discovered that the laws of diffraction--Lord Rayleigh's laws of diffraction--do not apply in the

writing phase. The writing phase is highly nonlinear. There is nothing that Lord Rayleigh

ever said that precludes you from recording, say, one-tenth micron spots or 500 Angstrom

spots.

And ff you look back in the literature, in a Journal called SP/E, the Society of

Photographic and Instrumentation Engineers, you'll find papers from good old Ampex about

recording 500 angstrom diameter holes which corresponded to an area density of nearly 1010

bits to the square inch.

The hooker comes when you realize that what Rayleigh's diffraction limit--the area of

the spot on the disk and all of that diffraction stuff--applies with a vengeance on playback. You

can't ignore it on playback.

And the Airy disk is Just like the gap loss function in magnetic recording. The only way

to make the gap loss function in magnetic recording smaller or shorter is to make smaller

gaps. The only way to make the area disk smaller in optical recording is either to think about

numerical apertures that are ridiculous, more than unity, or go to shorter and shorter

wavelengths.

At that time, using gas lasers, short wavelengths were available; and so, there were

experiments done with blue lasers. And that possibility doesn't seem to be on at the moment

with gallium arsenide. Gallium arsenide has an energy gap of about one electron volt, and that

means it puts out photons that are around 8,000 Angstroms in wavelength--800 nanometers.

And there are not many semiconductor materials with larger energy gaps than that. A

blue one at 4,000 Angstroms would need a 2 volt energy gap for instance.

So, we worked on WORMs. The basic trouble with a WORM is that it's a small module. A

WORM disk of reasonable diameter, 6 inches or 8 inches in diameter, is only going to hold a

gigabyte or so of data.

In the framework of Ampex thinking, that is nothing. That won't support digital video

for very long at all. Digital video recording--the standards for it--were beginning to be set in

the late 1970s; and Ampex, in fact, made the world's first digital video recorder.

It was a parallel access disk recorder, and it ran at 84 megabits per second. It was a

composite video being sampled at four times the color subcarrier.

1-191
And so, it was realized that making a WORM disk, an optical disk, with perhaps 1010

bits of information, wasn't going to support video for very long. So, that was canned.

The ROMs, the CD-ROMs, and the audio compact disk were never considered at Ampex

because they are best regarded as a publication means. They are just a replication; it's a way of

pressing disks to circulate information.

More or less at the same time, another pervasive idea in optical recording came up,

which is still going to this day. There is a well-known laboratory in Texas that is still

promoting the idea of doing holographic optical recording in three dimensions on crystals.

Ampex, of course, worked in that; the crystal, as always, was strontium niobate or lead

niobate.

And I could go on for some time, if I wanted to make it a technical talk, about what's

wrong with that idea. One of the things that is wrong with this holographic thing is that it

depends on extreme mechanical precision in doing the optics.

It is not for nothing that when you go into an optic lab that you see everything is being

done on granite blocks that are on air-bearing legs, and it's in an air- conditioned room.

Holography works Just fine, sending multiple beams through objectives. Lord knows in a

telescope, or in this thing, whatever number you want to say, I'll agree with it. A million beams

go through that lens.

But keeping them all in focus, keeping them all in the relative positions correctly,

requires a dimensional stability and a vibratlon-free environment that makes it unlikely that

it will work in any condition other than an optical bench in an air-conditioned room.

I'll tell you a little Joke about optical recording because after-dinner speakers are

supposed to tell jokes. It was told to me by a Dutchman, and the joke goes:

Do you know how you make a small fortune in optical recording? The answer is: You

are either Edward Rothschild, who every year teaches courses with names like technology

opportunity conference or something, or else you start with a large fortune --

(Laughter)

DR. MALLINSON: And that is exactly the way it has been in optical recording. Ask

Schlumberger, ask Honeywell, ask Storage Technology.

So, what have I got left? I_re got up there to about the mid-1970s; magneto-optic

recording is coming around again in this third reincarnation in the oxide phase. Bubbles

started to appear in the mid-1970s. Bubbles were, in my opinion, a loss leader right from the

very beginning. The claim made by Andrew Bobeck of bubbles was that you would be able to get

one million bubbles to the square inch and shift them at one million shifts per second.

Unfortunately, to do that, you had to have an entirely new material, a garnet substrate;

but all my materials scientist friends told me it was going to be considerably more expensive to

make than a silicon single crystal. That's overlooking the fact that single crystal silicon

substrates were already available.

And then, if you looked at the structures that were involved in bubble recording, they

were considerably more complicated; more area was required per bit cell. And bubbles have

never gone anywhere.

There are still Japanese companies working on bubbles; I believe Hitachi still works on

it. We at Ampex had a large bubble program because it was imagined, incorrectly, that bubbles

were somehow going to do something for recording.

1-192
It's this constantnotion that thereis somethingthere--somenew technology--that

hasn'tbeenthoughtthroughverycarefully;but it's new--new,new,new. Newis the nameof the

gamein research. That it woulddosomethingthat semiconductorshad not managedto do.I

answereda questionthis morningaboutsemiconductormemory;andbelieveit or not, good

old,long-sufferingAmpexhad a semiconductordivision downin SantaMonicain the L.A.

Basin,and it wasdedicatedto tryingto makea semiconductormemory.

And for thoseof youwhoweren'ttherethis morning,thebasictrouble with

semiconductormemoriesis that thereseemsto benochancethat theyaregoingto everbe

economically worthwhile.

Magneticrecording,overthelast 30 or 40years,has continued to double in density

every two or two and a half years.

I put forward the view this morning that the main reason that it was growing at that

rate for such a long period of time was that that was the rate at which the electronics industry

or the computer peripherals industry could accept technological change.

It Just so happens that, apart from glitches to do with the dumping of semiconductors

from you know where, the semiconductor industry has been doubling in density. They like to

say every two years. In other words, it is following just about the same slope.

A gigabyte of semiconductor memory at the moment costs you $500,000. A gigabit of

magnetic memory in hard disk costs you $1,000. So, there is a 500 to 1 differential in price;

and the two technologies are advancing down the same sort of maturity curve.

If you take literally the slight differences in slope, then you come to the conclusion that

they will reach equality in price in the year 2007. Now, that assumes that semiconductor

technology can continue to advance in density at its current rate and so can magnetic.

In semiconductor technology, there seem to be some enormous barriers to do with good

old diffraction of light coming up. Once you get down to quarter micron lines, it seems unlikely

that even ultraviolet extreme blue light diffraction will do it. And you will have to go to X-ray

lithography.

So, I don't believe that for a long time the semiconductor is going to be a threat to

magnetic recording. It took Ampex a long time to work that out.

What in fact has happened, looking back with 20/20 hindsight--a retrospective look at

things--is that every time there has been some advance in LSI, LSI has become larger, cheaper,

denser, whatever the criterion is that you like to use--what has happened is that it has enabled

some other form of recording to move to a higher level of performance.

At the Ampex Corporation, not only were rotary head video recorders invented in 1956,

but helical scan recorders were invented two years later, in 1958. The helical scan recorder was

invented because it had a long enough swipe down the length of the tape to get one whole

television frame in--field--I beg your pardon.

Unfortunately, the time base errors of the head tape interface were much too high to be

handled by the time base correctors that were in the early quad machines. The early quad

machines--the very first ones--had mercury delay lines. The later ones had quartz crystals,

where the delay time was changed by altering the voltage--the piezoelectric delay lines.

And that could not be used for the large timing errors in a long helical scan. Helical

scan machines languished in the lab as an idle curiosity for almost five years, until, all of a

sudden, I forget whether it was 8K or 16K DRAMs came along, that suddenly made it possible to

do the time base correction digitally.

1-193
So,it was silicontechnologythat enabledhelicalmachinesto be useful. Likewise,in an

opticaldisk at the moment--takethe audiocompactdisk--therawbit errorrate comingoffthe

disk, meetingthe Philipsor the manufacturingspecification,is 1byte--I shouldn't saybyte; I

promisedI wouldn'tsaybyte--let'ssay1bit errorin 1,000,I in 103,1in 104. In orderto getthe

errorrate satisfactoryfor audio,which is I in 1010,which is oneuncorrectedbit in left/right

stereoperhour. Large-scaleintegrationerror detectionand correction Reed-Solomon and

coding is used.

And Just like in the RDAT, the rotary digital audio transport, so it is in the order of

audio compact disk and the CD-ROM, that at any instant in time, no less than 64,000 bits of

data are coming through the electronics, in transit, being corrected. This is doing the whole

Reed-Solomon and coding business--you know, working out the syndrome, making the

corrections, and all of that, doing those polynomial divisions.

And I would submit that there is another example: the audio compact disk, CD-ROM, the

RDAT, rotary digital audio transport, are three machines which could not exist without largescale integration of silicon.

While I was still working at the University of California at San Diego, people would

repeatedly ask me-- the Chancellor and people like that; he was a psychologist of some kind; he

can be forgiven for asking a question like thls--but the question was repeated by other people,

too. It is: When will silicon memory displace magnetic recording?

And I think the answer is clear from history. It will never do it. What will happen, as

time goes on. is that the silicon memories that people use will get larger and larger and larger.

If they are a megabit now, they will be I0 megabits in 1995 and I00 megabits in the year 2000.

Meanwhile, the recorder itself will have continued to increase in capacity. So, if floppy

disks hold a megabit now, l megabit floppy disks won't exist ten years from now. They will all

be silicon devices. Floppy disks will have moved up to 100 megabits and so on.

So, from the point of view of a recording person like me, I regard silicon technology as

Just being an enabling technology; it makes things possible.

So, that has finished, I think, all my discussion of the various threats that were

thought. IX,e talked about electron beam recording of two kinds, optical recording of three

kinds, including a magneto-optic tape recorder. I've talked about bubbles; I've talked about

semiconductor memories, all of which must have cost Ampex an enormous amount of money

and for which there is basically nothing to show.

And basically in the whole recording industry, there is almost nothing to show. It

really is true--that sick Joke--about starting off with a large fortune.

I want to just finish by telling you just a quick snapshot, just four foils about what has

happened in recording.

(Showing of viewgraphs)

DR. MALLINSON: The most important thing that has happened since Mr. Poniatoffs

day, 1956, is that the density of magnetic particles has increased enormously.

And on the top left here is a 1956 Ampex tape; and this is a 1966 Ampex tape, a 1976

tape, and a 1986 tape. It is pure g-Ferric oxide, more pure g-Ferrlc oxide. Cobalt-doped g-Ferric

oxide, and metal particles. And there is a 1 micron marker down here, but you hardly need to

see that. It's perfectly evident to you that something very, very dramatic has happened over

that 30 year period in magnetic recording.

1-194
Thedensityofparticlesin this iron particletapeisjust 1,000timeshigherthan it was

in the 1956tape. Youmight ask: Well,why couldn'tAmpexJustjump to that immediately?

Theansweris that it is not makingsmall particlesthat's difficult; it is formulating them,

mixing them in the binder system,gettingthem uniformly dispersed--that'sthe difficult part.

It seemsto takea longtime.

Whenyou havea recordingmediumllke that--and metalparticletapein my view,was

the tapeofthe 1980s--Justasmetalevaporatedtapewill bethe tapeof the 1990s--withatape

like that with 1,000timesmoreparticlesperunit volume,youget--ffyou aretalking signal-tonoisepowerratios--Just1,000timesthe signal-to-noiseratio.

That means,track-width fortrack-width, wavelengthfor wavelength,1,000times the

signal-to-noisepowerratio, 30 dB signal-to-noiseratio.

(Changeof viewgraph)

DR.MALLINSON:Waysofusingthat. Forinstance,the D-2 machine,to showyou that

it reallyexists;someofyouhearddiscussiontodayaboutD-I andD- 2. But therearetwodigital

recordingstandardsat themoment.

TheD-2,which this is, takesthecomposite signal--that's the mixture of all the redblue-green, ff you will--and digitizes the whole thing at once; and a D-2 machine like this

records that around 148 megabits per second.

The D-1 machine separates out the components--the red/blue/green, ff you will--and

digitizes each separately. And consequently, it requires a higher data rate; the data rate is 216

megabits per second.

So, there are two digital video recorders being made and in production in the world

today: the D-I, which including overhead and eight audio channels and all of that, is 250

megabits per second; and the D-2 is 150 in this country and 160-something in Europe.

It's a rack-wired machine. The slot at the bottom takes cassettes.

(Change of viewgraph)

DR. MALLINSON: And the cassettes are called, not unreasonably, the large, the

medium, and the small. I've got the dimensions on them there.

Let's look at the large one. It's 421 millimeters by whatever it is. It records for 3.5

hours-- 210 minutes--soaking up in Europe at 164 megabits per second. At the end of that 3.5

hours, it will have recorded 2 times 1012 bits. So, there is 2 terabits there.

A cartridge like that is rather like two VHS cassettes put side by side. So, ff Mr.

Poniatoff was still around, I would tell him: Look, Alex, we really have got the TV end in a

drawer now. Now, we have this drawer; and you can put in probably five or six of those. You

can have close to 1014 bits.

It is also interesting since we have been talking about alternative technologies to

realize that one of those cartridges that costs about $500.00--I'm sorry; they are called

cassettes, not cartridges--has the same capacity as 30 IBM 3380 mainframe disk systems. And

the mainframe disk systems cost $ I00,000 apiece.

It is also equivalent in capacity to 40 two-sided 14 inch optical disks, which shows what

I was saying earlier on about Ampex deciding that optical disks didn't have any future for a

really high data rate or really large data storage is true.

1-195
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1-196
That D-2 is, in fact, I believe--and if anyone disagrees me, I would like to hear--'it is the

largest digital store, single module digital store, available in the world today; it is 2 terabits of

data.

(Change of viewgraph)

DR. MALLINSON: And just to show that I am not terribly prejudiced, here is another

development in rotary head machines, television recorders. This is Sony's experimental

digital high-definition TV recorder.

The simplest way to think about high-definition television is to think that it requires

about five times the number of bits per frame as a regular television. Regular TV means about 3

megablts per frame; HDTV is about 30 megabits per frame.

Another way of thinking about HDTV is that it is rather like high resolution computer

graphics that you might find on some work station, except the difference is that In TV you've

got to put up an image, 30 of them per second. And_the data rate with a recorder like this has to

record is I, 100 megabits per second, I. 1 gigabits per second. And it is achieved; it is a rotary

head machine. There is a rotary head hidden under there.

In this particular machine, which was made in 1984--it's not new technology by any

means--it was achieved with six heads. So, each one of the heads contacting the tape was

running at something llke 180 or 190 megabits per second.

When I left Ampex in 1984, it was considered conservative practice in the design of

machines to run at 80 megabits per second. This is higher-- 190. If you ask me what's the

world's record at the moment in the published literature for a magnetic head, actually writing

and playing back, it is a mind-blowing 300 megabits per second. So, I think Ampex was right

in Its decision; there was no other technology that was going to achieve such high data rates as

magnetic recording.

A recorder like this records HDTV at 1,100 megablts per second for one hour; and the

capacity, when you've finished, of these 12 inch reels is--it says at the bottom--4.5 terabits,

which is equivalent to 100 two-sided 14 inch optical disks.

The race is on in all the recording companies these days to try and reduce the number of

heads. It would be nlce to get the number of heads down to four, for instance, not six.

So, that's enough for the foils.

The conclusion I want you to draw is that I told you the story about 25 years of R&D in

the Ampex Corporation and a great deal of money and time and very skilled people's efforts

were spent on activities which led nowhere. They did not lead to the goal of having extremely

large databases to be accessed at extremely high data rates.

And I think that is the end of my talk. Thank you for your attention.

(Applause)

DR. MALLINSON: Questions?

PARTICIPANT: Do you remember-- (Inaudible}

DR. MALLINSON: No.

PARTICIPANT: It was a holographic computer memory.

1-197
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1-199
4.2.2 DIGITAL COMPONENT HDTV RECORDER

SONY HDD-1000 (Prototype only)

SONY SONY

27 "

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Sampling rates are: 74:27:27 x 106 sample/sec

Video bit rate is ii00 + o/h Mbs

8 digital audio (48/16) channels also recorded (2 Mbs/channel)

Gross bit rate: about 1200 Mbs

Playing time: 63 minutes

Capacity: 4.5 1012 bits (i00 x 14" optical discs)

1-200: --
DR. MALLINSON: No.

PARTICIPANT: (Inaudible)

DR. MALLINSON: It was a scan?

PARTICIPANT: Yes. It was in Time magazine. (Inaudible)

DR. MALLINSON: No, no. I don't recall that.

PARTICIPANT: (Inaudible)

DR. MALLINSON: You know, that has to limit the time one talks. I could talk for hours

about this; I find it fascinating. And I would like to be able to say a few things about what you

are supposed to learn from all this. Well, I suppose the things that you can learn from this is--

and my remarks are Just to do with tape recording--the goal of the Ampex Corporation is to

record enormous databases, terabit databases, and access them at gigabit per second rates.

I think the message is that nothing will displace magnetic recording unless it is

extremely simple; magnetic recording is done on a simple, chemically stable, featureless

medium, it's cheap to make, it's cheap to implement.

I read all the excitement there is today about scanning tunneling microscopes; lo and

behold, IBM can write IBM in some--do you remember what it was? Lithium or something?

Xenon. It is evaporated away as soon as they let the temperature go up.

Then, the question is: Is there any reason to think that the very extreme high

resolution of scanning tunneling microscopy--atomic resolution--will ever turn out to be a

useful recording device? I think not.

Another one is atomic force microscopy, where you have a little magnetic tip that you

measure the magnetic force over some substrate by vibrating it with a piezoelectric element

and all of that. I think that one is even less likely to be a high density, fast access memory. In

fact, I would add to the llst of requirements that not only must the medium be cheap and

featureless and stable, but there must be the requirement that you must be able to read every bit

in at least 10 nanoseconds because 10 nanoseconds .corresponds to I00 megabits per second.

And in fact, since all these magnetic recorders operate at that rate, and the 300 megabits

per second I was talking about is only 3 nanoseconds to read each bit, a prerequirement really

ought to be that you can read everything in just a few nanoseconds.

And then, there is the question of access time. Is there a way of accessing large

distances? And is there a way of increasing the size of the recording medium to almost

indefinitely large areas?

Questions like that, in atomic tunneling microscopy and atomic force microscopy, that

I have found wanting.

PARTICIPANT: (Inaudible)

DR. MALLINSON: What I'm hearing is set size and tape height.

PARTICIPANT: Set size and tape height -- (Inaudible)

DR MALLINSON: Cassette size?

PARTICIPANT: Yes. Real size -- (Inaudible)

1-201
PARTICIPANT:What's the differencein tensionon the varioussizesof cartridgesthat

you displayed?Andhow doesthat affect-- (inaudible)

DR.MALLINSON:I hardlyknowhowto answer. I mean,a standardtapeis abouta

poundperinch ofwidth, othersarehalf-inch;andit is expectedin videotaperecorderswhere

the tapecontactsthe headthat the headshallbewearingdownat the rateof about I0 microns

perhour.

So,it's expectedthat thewear-outtimeof theheadwill beabout2,000hours.

And a remarkaboutcassettesmayinterestyou.Thereis not a singlecassettemade--the

D-1,the D-2, the8 millimeter,theVHS,thelatelamentedBetamax--thatevenachieves20

percentvolumepackingefficiencyof the enclosure.

So,in orderto havethat conveniencein magneticrecordingin the cassette,which is

simply theconveniencethat youcan stick the thing in and pull it out at any time, you have

given up a factor of 5 in volume packing density. 80 percent of the space inside the cassette is

space, and they are still by far the highest volumetric packing factor devices in the world. With

regard to another part of your question, I forgot to mention that it's funny that we used to be so

worried about the tape contacting the head because any video tape now--even going by a VHS

tape--to meet the specifications for VHS tape, it must stand one hour of still framing, which is

something like 50,000 sequential passes of the head on the same track, without any

measurable change.

And many of them will run for 10 hours.

PARTICIPANT: I have a question about tradeoff between areal density and the number

of read -- (Inaudible)

DR. MALLINSON: There is nothing specifically about ID- I. I would be very surprised ff

any tape showed any deterioration in 100 reads. I'd even be surprised if it didn't go to 1,000

reads.

PARTICIPANT: (Inaudible)

DR. MALLINSON: I'm missing one word--the projection on the particle size?

PARTICIPANT: Yes.

PARTICIPANT: Could you repeat the question, please?

DR. MALLINSON: I think the question is: Do I have any idea of projections of the

particle size? With iron particles that are in maybe RDAT and D-2 at the moment, they are

around 1,200 Angstroms long and about 200 Angstroms wide. And it's interesting about that

200 Angstroms, incidentally, because I said this morning that various physicists have come up

with the idea that there must be a quantum mechanical limit to recording density.

And my usual stock way is telling you the way to think about it some more is to tell

them that in a single iron particle, 280 Angstroms in diameter, the flux flow is precisely one

fluxon. Fluxons -- quantized magnetism has something to do with superconducting systems.

not regular systems.

So, they are 1,200 by 200, and they will get smaller no doubt in the contact duplicating

versions of DAT tape. The particle size is 800 angstroms long.

In the metallic thin films, the stuff I was talking about this morning, the metallic

grains are 2 microinches by 2 microinches, 500 angstroms by 500.

1-202
There are media around at the moment which have a factor of 10 higher packing

density than the iron particle tape, That's the name of the game with media; that's all you're

doing. Raising the coercive force is a pain in the neck. It means more current has to go into the

head; the medium must saturate; and who wants four times or five times the coercive force and

25 times the recording power'?

The only reason you need it is to use smaller particles and get higher signal-to-nolse

ratios Any more questions?

[No response)

DR. MALLINSON: Thank you.

*U.S. GOVERNMENT PRINTING OFFICE: 1992-627-150/60015

1-203
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1, AGENCY USE ONLY (Leave b/_mk) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

September 1992 Conference Publication, July 23-251 1991

4.

6.

7.

TITLE AND SUBTITLE

NSSDC Conference on Mass Storage Systems and Technologies for

Space and Earth Science Applications

Volume I

AUTHOR(S)

Ben Kobler, P. C. Harihazsn, and L. G. Blasso, Editors

PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES)

NASA-Goddard Space Flight Center

Greenbelt, Maryland 20771

9. SPONSORING/MONITORING AGENCYNAME(S)ANDADDRESS(ES)

National Aeronautics and Space Administration

Washington, D.C. 20546-0001

S. FUNDING NUMBERS

JON-933-656-80-02-26

8. PERFORMING ORGANIZATION

REPORT NUMBER

92B00093

Code 933

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

NASA CP-3165, Vol. I

11. SUPPLEMENTARY NOTES

Kobler: Goddard Space Flight Center, Greenbelt, MD;

Hariharan and Blasso: STX Comoration*, Lanham, MD.

*Hughes STX Corporation as of October 1, 1991

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13. ABSTRACT (Maximum 200 words)

This report contains copies of nearly all of the technical papers and viewgraphs presented at the NSSDC

Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications. This

conference served as a broad forum for the discussion of a number of important issues in the field of

mass storage systems. Topics include magnetic disk and tape technologies, optical disk and tape, software storage and file management systems, and experiences with the use of a large, distributed storage

system. The technical presentations describe, among other things, integrated mass storage systems that

are expected to be available commercially. Also included is a series of presentations from Federal Government organizations and research institutions covering their mass storage requirements for the 1990s.

14.suaJecrTtRMS

Magnetic tape, magnetic disk, optical disk, mass storage, software storage

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