From: carolyn@usenix.ORG (Carolyn Carr)
Newsgroups: comp.org.usenix
Subject: USENIX Summer '92 Conference Report
Keywords: USENIX Association
Date: 24 Jul 92 19:21:28 GMT
Organization: Usenix Association Office, Berkeley


USENIX Summer '92 Conference Report
***********************************

Best Paper Winners

Doug Moen of Sietec Open Systems Division was 
given the Best Paper Award for "A Discipline of 
Error Handling."

Mary Baker and Mark Sullivan, UC Berkeley
authors of "The Recover Box", won the Best
Student Paper Award.

Both papers have been published in the USENIX 
Summer 1992 Technical Conference Proceedings.


Works-in-Progress Report: 
Organized by Lisa A. Bloch, Sun User Group and 
coordinated by Peg Schafer, BBN Systems

A Hybrid Performance Model for NFS File
Servers, David N. Williams, Ericsson Network Systems, 
Richardson, TX <exudnw@exu.ericsson.se>

In this session we will report on a Hybrid simula-
tion model of NFS client-server transactions.

Our current environment consists of over 400 
diskless SPARC workstations supported by nine 
Sune 4/490 active servers. Benchmarks combined 
with trial and error were the prime methods used 
in arriving at the current configuration.

A number of benchmarks exist to assist in select-
ing and tuning NFS servers, but benchmarking 
has its perils and limitations. Vendor-supplied 
benchmark numbers are frequently suspect, and 
not every organization has the resources or skills 
required to achieve accurate and meaningful 
results. Even after spending extensive time 
benchmarking a server, the results may not pro-
vide sufficient information on how it will work in 
a specific environment.

A discrete event simulation model of the NFS 
client-server relationship has been built which 
provides an approximate model of existing or 
proposed client-server configurations. The model 
allows for flexibility in changing parameters and 
does not require the investment in time, and pos-
sibly money, that comes with benchmarking.

Phonestation: Moving the telephone onto the
Virtual Desktop, Stephen Uhler, Bellcore
<sau@bellcore.com> 

The PhoneStation system is a tool that allows a 
Sun SPARCstation to control an ordinary tele-
phone line. It consists of: 1) a micro-controller 
that interfaces a telephone line with a SPARCsta-
tion via a serial port and the audio connector, 2) a 
software library for the SPARCstation that pro-
vides telephone interface control, digital signal 
processing (e.g., touch-tone detection), and text 
to speech conversion, and 3) a TCL based lan-
guage for writing telephone applications.

As an example, the system can be used to inte-
grate answering machine functionality into the 
workstation environment. Voice messages 
appear as ordinary electronic mail and are played 
through the SPARCstation speaker. If mail is read 
from a dumb terminal, the PhoneStation system 
places a call to a user specified telephone number 
and plays the voice portions of any messages.

Texas: An efficient, highly compatible persistent ob-
ject store using pointer swizzling at page fault time

Vivek Singhal, University of Texas at Austin 
<singhal@cs.utexas.edu>

Texas is a persistent object store that implements 
huge address spaces efficiently on standard hard-
ware. Pointer swizzling (address translation) at 
page fault time converts the pointers in a page 
from a long format into normal, hardware-sup-
ported virtual addresses when pages are brought 
into memory. This translation is transparent to 
compiled programs, allowing the use of existing 
compilers with little or no modification. Modern 
UNIXes such as SVR4 and OSF/1 provide the 
necessary control over virtual memory with no 
modifications to the operating system.

Gumby: The portable, high-performance file system 
that rides on the back of your Pokey file system 
Sheetal V. Kakkad, University of Texas at Austin

Gumby is a simple log-structured file system 
built on a normal UNIX file system. The file sys-
tem is built inside a single UNIX file, requiring no 
dependencies on underlying disk geometry, so it 
is quite portable. Log structure avoids the use of 
a single "home" disk block for a logical file block, 
allowing any block to be written anywhere. This 
optimizes the file system for use with large RAM 
caches, which tend to absorb most reads and 
increase the proportion of writes. We intend to 
experiment with reordering read-only pages as 
well, to dynamically increase locality and reduce 
seeks caused by read misses.

Knowledge-Based Systems Construction in C++,
Vladimir Bacvanski, Aachen University of Tech-
nology, Germany <vladimir@rwthi3.informatik.rwth-aachen.de>

The examination of an applicability of appealing 
techniques from object-oriented software engi-
neering to knowledge-based systems domain is 
discussed, focusing on the promising role of C++ 
in this context. The entrance of expert systems 
into real industrial application arena has uncov-
ered weak points of the current knowledge-based 
systems technology, especially the incomprehen-
sibility, poor performance, and inability to inte-
grate with non-knowledge-based systems.

The use of C++ for building technical expert sys-
tems should provide one possible framework for 
overcoming the current deficiencies. The code of 
a knowledge representation language is trans-
lated into C++, bringing the possibility to use 
knowledge-based techniques while remaining in 
the well known environment, so that developers 
do not have to abandon all their skills and move 
to expensive and incompatible specialized artifi-
cial intelligence workstations. Moreover, the 
combination of multiple paradigms (object-ori-
ented, procedural, and the rule-based one) in the 
C++ framework produces a synergetic result.

A new multi-paradigm system architecture is 
examined together with mechanisms which 
diminish the impedance mismatch between 
object-oriented knowledge and non-knowledge-
based systems, providing interchangeability of 
objects which follow different paradigms. The 
object-oriented paradigm is used not only to 
model the applications, but the system's internal 
components as well. The correspondence 
between different constructs from the object-ori-
ented and knowledge-based systems will be 
investigated, showing that it is possible and prof-
itable to model knowledge-based systems with a 
set of C++ classes.

Development of an event based debugger with source 
level capabilities, J. G. Posthuma, J. Scholten, J. G. Wijnstra;
U. Twente, Netherlands <posthuma@cs.utwente.nl>

Finding a bug in an application is time consum-
ing and expensive. For parallel applications, 
debugging is even harder. The behavior of paral-
lel applications can only be understood by look-
ing at them with great abstraction. Only specified 
events of the system should be presented to the 
user. But such events only give a hint where a bug 
could be. After this hint, the user has to look with 
greater detail. He should be able to specify both 
events of higher abstraction (for example com-
munication) and source level debug events.

Events are the basis of the debugger. An event is 
generated each time an important point is 
reached in the execution. These points can be 
specified by the programmer. An event will often 
be used to indicate a place where interaction 
between two processes takes place, since interac-
tion is an important aspect of parallel applica-
tions. The events of all processes are merged into 
one event stream. This stream can be used 
directly or stored in a database for later use. For a 
long running or multi-process application, the 
event stream can be quite voluminous. That is 
why a number of tools are provided to make the 
event stream data more manageable. The pro-
grammer has the possibility of reducing the com-
plexity by specifying filters, which remove those 
events in which the user is not interested.

Another important tool is the behavior recog-
nizer. A recognizer matches behavior as specified 
by the user in terms of events against the event 
stream generated by the application. It is not only 
possible to specify the expected behavior, but also 
the behavior that is not allowed. Recognizers can 
be used in a number of ways. First of all they can 
be used to trace down the places where the spec-
ified behavior is violated. Secondly, recognizers 
are useful to summarize the behavior by replac-
ing a number of events from the stream with one 
new high level event. This allows the program-
mer to analyze the system at different levels of 
abstraction. A third possibility is to use recogniz-
ers to specify interesting points in execution 
where some action must be performed, like a 
request for process status. This last option is only 
possible for run time debugging. The recognizers 
are also useful for analyzing events in the data-
base.

The debugger is a mixture of an event based 
debugger, source level debugge, and a behavior 
recognition system. The event based part of the 
debugger concentrates on distributed aspects of 
the application and can be used during or after 
execution. It is not always possible to debug an 
application when using the event based ap-
proach. That is why the normal source level 
debugger will be integrated in the design. In the 
future, other features may be added, in order to 
make it a complete debugger for distributed 
applications.

MACH on a Physically Secure Crypto Coprocessor
Elaine Palmer, IBM Research Division, Yorktown 
Heights, New York <epalmer@watson.ibm.com>

I will present an overview of a secure crypto-
graphic workstation coprocessor. The prototype 
hardware, named `Citadel', was completed in 
1991 at IBM's T.J. Watson Research Center. It can 
perform DES encryption and decryption of data 
at high speeds.

We envision its use in three possible application 
environments:

 1. It can be embedded in a communications con-
troller (wire or fiber) to encrypt or decrypt some 
or all network traffic.

 2. It can be embedded in a disk controller to 
encrypt or decrypt selected files or an entire disk.

 3. It can be installed as a secure, general purpose 
crypto coprocessor on a microchannel bus. In this 
environment it can be used to encrypt or decrypt 
passwords, authenticate users and requests for 
resources, encrypt or decrypt transactions, or 
process sensitive data from the main host proces-
sor.

In all three applications, encryption and decryp-
tion does not degrade the throughput of its host 
device. The host for our prototype is an IBM
PS/2.

The hardware and kernel software are designed 
to operate in a physically secure package. If the 
package detects tampering, it responds by eras-
ing its encryption keys and other secure memory. 
The system software is a small, multitasking 
microkernel, Mach 3.0, from Carnegie Mellon 
University. I will discuss the advantages and the 
disadvantages we've encountered in using Mach 
for this project.

BOF Report

by Rich Salz, Open Software Foundation
<rsalz@osf.org> 

A good BOF can be one of the best things to do at 
a USENIX Conference - it can keep you going all 
night.

BOF stands for Birds of a Feather, as in "flock 
together." It's an informal gathering of people 
who are interested in a particular area. Many 
BOFs are scheduled before the conference and 
announced in the conference schedule. Others are 
"scheduled" on site, and announced by posting a 
notice on the general message board. BOFs are 
not part of the standard conference track. They 
are generally held after-hours and anyone can 
attend. Many of them ``adjourn to the bar,'' where 
the discussions can go on for hours.

This Summer Conference's BOF topics included: 
a discussion of Standards (POSIX et al), Distrib-
uted Systems Administration, Gays in comput-
ing, EFF, FSF, Usenet, NNTP, UUNET, Ultrix, Alpha, 
BSD4.4, BSDI, and Obfuscated C. I think one of the 
best things to do is to go to an area that's new to 
you. It's a great way to get practical knowledge in 
an informal setting, and a good way to meet 
experts in the field.

Unfortunately, I didn't do that this year: I went to 
the Usenet-related BOFs because I "had to," and 
others because I wanted to get a status report. So, 
while there were no doubt lots of good things 
happening at FSF, EFF, Distributed Systems, and 
so on, I can't tell you about them.

Tuesday: News Software & USENET

This BOF was run by Henry Spencer and Geoff 
Collyer. It started with an update on C News. The 
Performance Release (including much work done 
by Geoff for UUNET) is out, and the Clean-Up 
Release won't be out for ``quite a while.'' This 
next release will have a revised source tree, and 
(to the cheers of the crowd) most of the build 
work will be done directly in the Makefiles.

News volume is still doubling yearly, and the 
growth in newsgroups is (apparently) causing 
problems for some newsreaders, most noticeably 
when sorting the active file or deleting a news-
group. Newsreader writers, beware: the net is 
growing faster than you think!

The volume and newsreaders then led into a dis-
cussion of threads programs like trn. Geoff is 
thinking about looking into the issue of threads 
databases, saying ``mthreads must go.'' On the 
other hand, we did get to hear the only nice thing 
Geoff has ever said about NFS: ``for reading 
news, NFS is pretty good.'' There was also talk 
about changing the news filesystem format, to 
which Geoff replied ``fix namei.''

Bruce Jones, from the School of Communications 
at UCSD, is doing his doctorate on the growth of 
Usenet. He has Henry's old tapes from the start of 
Usenet and is trying to gauge the interest in get-
ting a CD-ROM of, say, the first A News ``Car for 
Sale'' ad. If you're interested, send email to 
<bjones@ucsd.edu>.

Stan Barber spoke about the next release of NNTP. 
The client and server code has been split into 
pieces and the client code is in beta-test. It's 
already been ported to some PCs. The new server 
should go into alpha-test in July. If you have some 
new feature or bug fixes, let Stan know. In partic-
ular, if you can help make it work well with C 
News he'd like to hear from you. Stan can be 
reached as <nntp@tmc.edu>.

Wednesday Night BOFs

On Wednesday I attended the standard Usenet 
and hackers BOF track: UUNET, Obfuscated C, 
BSDI, and 4.4BSD. Even though each was only an 
hour long, this was a long night.

Unfortunately, I missed most of the UUNET BOF. I 
wandered in during a discussion of Alternet 
(UUNET's commercial IP network, no traffic 
restrictions). People are interested in low-cost 
methods like dial-up IP service. Rick Adams 
mentioned a bit about how the FBI is a customer. 
People concerned about the FBI reading netnews 
should make a reality check: the FBI wants to 
catch serial killers, they couldn't care less about 
obnoxious netnews postings!

UUNET has also written another version of UUCP. 
BSDI has licensed it, and all UUNET customers 
will probably be able to get it, too. The most inter-
esting thing about the UUNET UUCP is that you 
can replace the front-end configuration files so 
that it looks like whatever version of UUCP you 
want it to. Only BSD is supported, but HDB is an 
obvious next choice.

Every year Landon Noll asks the people of 
Usenet to send him the most twisted C code they 
can write, and in the spring and summer he and 
his group evaluate the results and pick the best 
(or is it the worst?) they can find. No program 
could be more than 1,536 bytes of non-white-
space, and no ``cc'' line could be more than 256 
bytes. Lots of whitespace was allowed this year, 
which made most of the programs a little less fun 
to look at. For the first time, there were more non-
US winners that those from the United States. 
Every year, this is one of the best BOFs: it's very 
technical, in a weird sort of way, and it's very 
funny.

I also detected a decided ``tools'' bent to this 
year's winners. It would have made a nice con-
trast to the FSF BOF. While GNU software does lots 
of nice things, nobody will ever say it's small. At 
the Obfuscated C BOF, however, we got to see a 
chess program (written by Vern Paxson, the 
author of flex) that reportedly held its own 
against GNU Chess. There was also a make-like 
program that had some novel features. Both of 
these listings could fit on a single page!

The full results will be posted to the net (in com-
p.lang.c, misc.misc, and other places) in a month 
or two. Landon also warned people that he and 
Larry Wall are working on an obfuscated Perl 
contest, which many in the crowd thought was 
kind of redundant.

Berkeley Systems Design, Inc., (BSDI) is a new 
start-up that is selling BSD operating systems for 
the 386-family of machines. It's a small company, 
still struggling to meet their weekly payroll. For 
about a thousand dollars, you get the full source 
code to BSD, X, NFS, and other tools - and binaries 
to run it on your IBM PC or clone. This was the 
most overtly commercial BOF I attended: Rob 
Kolstad is an entertaining speaker, but it was 
clearly a vendor presentation. It gave information 
people clearly wanted to hear, however: the room 
was packed. The part I found most interesting 
was that USL (the branch of AT&T in charge of 
Unix) is suing BSDI. While you can never be sure 
when lawyers are involved, it would seem that 
they are taking exception to the claim that the 
Berkeley "Net II" release, upon which BSDI's 
product is based, is unencumbered. I'm guessing 
that BSDI was picked because they are the first 
commercial venture that hasn't bought some sort 
of license from AT&T. For more information on 
BSDI, contact <info@bsdi.com>.

The last BOF of the evening was the 4.4BSD BOF, 
led by Kirk McKusick and Keith Bostic of Com-
puter Systems Research Group. The schedule 
said that this would include a report on the 
release schedule for 4.4BSD. This was very 
unusual as the CSRG folks from Berkeley have 
never previously announced their release sched-
ule. Anyhow, 4.4 will be available in two formats: 
4.4 and 4.4 "light." The former will require an 
AT&T license; the latter will contain only the 
freely-redistributable source code. This will be 
more complete than earlier free releases, but will 
still need some work on the kernel. Both the alpha 
and the final release will be available in both for-
mats.

4.4 will have lots of filesystem features: 64 bit file-
sizes (using the longlong datatype), NFS ``leases'' 
that make NFS more efficient and robust, stack-
able filesystems (similar to what David Rosenthal 
discussed at Baltimore; the BSD work comes from 
UCLA and the Ficus project), /dev/fd, the log-
based filesystem (from Sprite), and so on. It will 
also make uid and gid be 32 bits, further changing 
the stat structure. These changes will all be in the 
alpha release because they involve changes in the 
system interface. The final release will have new 
TCP/IP work from Van Jacobson, the Berkeley 
streams package, and probably a new virtual 
memory system (from Mach). It will also contain 
as many documentation updates and bug fixes as 
possible. Sun has donated their shared library 
architecture, and that may also be a part of 4.4. I 
can't read my notes at this point, but I think the 
supported architectures include the Sparc, 
HP9000, Tahoe, and others.

The bad news is that once 4.4 is solidly out the 
door, the CSRG Group is shutting down. They 
explained that it is hard to get more funding, the 
University is using BSD less, it is too big for the 
current group to develop, and that the past year 
has not been fun: too much politics and name-
calling. It's probably safe to say that the worksta-
tion industry would not have happened without 
BSD, and that many of us would be doomed to be 
filling out RPG II forms in dimly-lit cubicles. 
Thanks, guys!

Thursday BOFs

Thursday night is always a questionable night for 
BOFs because things are always scattershot after 
the USENIX reception. This didn't stop me from 
scheduling the third Usenet-type BOF of the con-
ference, however. This one concentrated on 
NNTP. The NNTP protocol is being revised by an 
Internet Engineering Task Force committee. Most 
of the revisions are related to supporting batching 
and other facilities for low-speed links. The cur-
rent draft is available for FTP from turbo.bio.net 
in ~ftp/ietf-nntp. The group is not concentrating 
on facilities for news-readers. There is an unoffi-
cial group working on that; send mail to
<David_ascher@brown.edu> if you are interested in 
that area.

Stan Barber gave another preview of upcoming 
NNTP releases and asked for some feedback on 
specific changes to the client-side inews that is 
part of NNTP. This led to some discussion about 
news headers. There were lots of questions for me 
about INN, my Usenet/NNTP implementation. I 
mentioned it at last year's BOF and presented a 
paper on it this year so people were fairly curi-
ous. By the time you read this, the software 
should be available, however, so I won't take up 
any more space on self-aggrandizement.

One last-minute BOF that was held on Thursday 
was for archive maintainers. This group is start-
ing a very exciting project to make a universal 
card-catalog for software available on the net. 
Many of the people involved -- Rich Morin, Ed 
Vilmietti -- have lots of experience with public 
archives, and it sounds like they have a good plan 
of attack. For more information, contact cfcl!rich.

Well, that's it. I hope you thought this useful, and 
that it spurred your interest to become a full-
fledged USENIX BOFfer.