of Commerce

National Bureau

of Standards

Computer Science

and Technology

NQS

PUBLICATIONS

NBS Special Publication 500-110

Microcomputers:

Introduction to

Features and Uses

QO

IGf)

.U57

500-110
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act ot Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology

and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides; (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and

the Institute for Computer Sciences and Technology.

THE NATIONAL MEASUREMENT LABORATORY provides the national system of

physical and chemical and materials measurement; coordinates the system with measurement

systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific community, industry,

and commerce; conducts materials research leading to improved methods of measurement,

standards, and data on the properties of materials needed by industry, commerce, educational

institutions, and Government; provides advisory and research services to other Government

agencies; develops, produces, and distributes Standard Reference Materials; and provides

calibration services. The Laboratory consists of the following centers:

Absolute Physical Quantities-^ — Radiation Research — Chemical Physics —

Analytical Chemistry — Materials Science

THE NATIONAL ENGINEERING LABORATORY provides technology and technical ser- vices to the public and private sectors to address national needs and to solve national problems; conducts' research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary disciplines required to carry out this research and technical service; develops engineering data and measurement capabilities;

provides engineering measurement traceability services; develops test methods and proposes

engineering standards and code changes; develops and proposes new engineering practices;

and develops and improves mechanisms to transfer results of its research to the ultimate user. The Laboratory consists of the following centers:

Applied Mathematics — Electronics and Electrical Engineering^ — Manufacturing

Engineering — Building Technology — Fire Research — Chemical Engineering-^

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts

research and provides scientific and technical services to aid Federal agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and

economy in Government operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing the Federal Information Processing Standards Program, developing Federal ADP standards

guidelines, and managing Federal participation in ADP voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and

provides the technical foundation for computer-related policies of the Federal Government.

The Institute consists of the following centers;

Programming Science and Technology — Computer Systems Engineering.

'Headquarters and Laboratories at Gailhersburg, MD, unless otherwise noted; mailing address Washington, DC 20234. ^Some divisions within the center are located at Boulder, CO 80303.
and Technology

NBS Special Publication 500-110

Microcomputers:

Introduction to

Features and Uses

OF STAUD/iJiDS Computer Science gc^

I 00

'500 -

1

Myron Hecht

Herbert Hecht

Laurence Press

SoHaR Incorporated

1040 South LaJolla Avenue

Los Angeles, CA 90035

Sponsored by:

Institute for Computer Sciences and Technology

National Bureau of Standards

Washington, DC 20234

U.S. DEPARTMENT OF COMMERCE

Malcoim Baldrige, Secretary

National Bureau of Standards

Ernest Ambler, Director

Issued March 1984
Reports on Computer Science and Technology

The National Bureau of Standards has a special responsibility within the Federal

Government for computer science and technology activities. The programs of the

NBS Institute for Computer Sciences and Technology are designed to provide ADP

standards, guidelines, and technical advisory services to improve the effectiveness

of computer utilization in the Federal sector, and to perform appropriate research

and development efforts as foundation for such activities and programs. This

publication series will report these NBS efforts to the Federal computer community as

well as to interested specialists in the academic and private sectors. Those wishing

to receive notices of publications in this series should complete and return the form

at the end of this publication.

National Bureau of Standards Special Publication 500-110

Natl. Bur. Stand. (U.S.), Spec. Publ. 500-110, 144 pages (Mar. 1984)

CODEN: XNBSAV

Library of Congress Catalog Card Number: 84-601005

U.S GOVERNMENT PRINTING OFFICE WASHINGTON: 1984

For sale by the Superintendent ol Documents, U S, Government Printing Oltice, Washington. DC 20402
TABLE OF OONTEKIS

LIST OF FIGURES V

LIST OF TABLES ......... vi

EXECUTIVE SUMMARY viii

ABSTRACT AND KEYWORDS 1

1 INTRODUCnCW 2

1.1. Motivation 2

1.2. Federal Regulations Affecting

Microcomputer Procuronent and Use 4

1.3. Contents of this Report. 5

1.4. Disclaimer and Trademark Identifications 6

2 OVERVIEW OF MICROOOMPUTERS 7

2.1. What Is a Microcomputer 7

2.2. Microcomputer Hardware . 7

2.3. Systems Software 25

2.4. Programming Languages 30

2.5. The User Interface 36

2.6 Types of Microconputers 38

3 FEDERM. USERS 42

3.1. Clerical Users 45

3.2. Administrative Users 47

3.3. Professional Users . , . , 49

3.4. Technical Users. 52

4 MICROCBMEOTER APPLICATIONS 54

4.1. Word Processing 55

4.2. Data Management Software 58

4.3. Spread Sheet Processors 64

4.4. Graphics Software 68

4.5. Microcomputer Canmunications 77

4.6. Specialized Software 85

4.7. Application Integration 86

iii
lABLE OF OGNTOnS

(continued)

5 mxPGEMEtrr issues of MCROGQMFUTERS 90

5.1. Motivation for Using Microcomputers 90

5.2. Costs of Microcomputer Systems 92

5.3. Risks of Microconputers 94

5.4. Prevention of Problems 97

5.5. Sources of Microconputers 100

6 OCNCLUSION 105

6.1. Summary of Key Points 105

6.2. Useful Areas for Guidelines and Standardization Activities . . .107

REFERENCES Ill

APPENDIX A - GLOSSARY 118

APPENDIX B - ANNOTATED BIBLIOGRAPHY 127

iv
LIST OF FIGORES

Figure Title Page

1-1 Projected Growth of Microcomputer Installations 3

2-1 Microcomputer Hardware Devices 8

2-2 ASCII Characters Displayed as a Series of Dots 17

2-3 Integrated Circuit and Socket 23

2-4 Printed Circuit Board 23

2-5 Assembly Language and High Order Language

Representations of a Division of IWo Numbers 31

4-1 Representation of Data in a File Management Syston 59

4-2 Report Created by the Data Managonent System 60

4-3 Sample Spread Sheet Model 65

4-4 Types of Graphics for Display of Numerical Data 69

4-5 Scatter Plot Produced by Character Printer 71

4-6 Scatter Plot Produced by Dot Matrix Printer with

Software Controlling Each Dot Individually 72

4-7 Plot Produced by Fully Formed Character Printer

with Precision Position Control 73

4-8 Scatter Plot Produced by Plotter 74

4-9 Topologies for Local Area Networks 83

V
LIST OF OyVBLES

Table Title Page

2-1 Major Microcanputer Hardware Components 9

2-2 Cannon Microprocessors 11

2-3 Floppy Disks 13

2-4 Camion Pointing Devices 15

2-5 Types of Integrated Circuits 24

2-6 General Functions of Systems Software 26

2-7 Configurations of Operating Systems 28

2-8 Common Higher Order Languages Used in

Microcomputers 33

3-1 Job Functions of the User Classifications 43

3-2 Characteristics of User Classes 44

3-3 Clerical User Characteristics and

Desirable Syston Attributes 46

3-4 Administrative User Characteristics and

Desirable System Attributes 48

3-5 Professional User Characteristics and

Desirable System Attributes 50

3-6 Technical User Characteristics and

Desirable Syston Attributes 53

vi
LIST OF TABLES

(continued)

Table Title Page

4-1 Types of /^plication Software 54

4-2 Uses of Word Processing 56

4-3 Classes of Microcomputer- Based

Data Management Software 61

4-4 Uses of File and Data Base Management Software 63

4-5 Uses of Spread Sheet Programs 67

4-6 Characteristics of Graphics Hard Copy Output 70

4-7 Graphics Software i^lications 76

4-8 implications of Communications Software 78

4-9 i^lication Integration 88

6-1 implications of Microcomputers to

Classes of Users 91

6-2 Microcomputer Cost Factors 92

vii
Executive Surnnary

EXECUTIVE SUMMARY

This report describes microcomputers, their uses, and costs. Its objectives

j are to introduce microcomputers to readers with some knowledge of computing ! but little or no background in microccmputers and to identify important issues

associated with their implementation in Government agencies.

Because of their low cost, microconputers provide an opportunity to automate | activities in ways that had previously not been achievable. In addition, they

can provide a Icwer cost alternative to executing similar programs on larger ; systems while providing users with more control over the computer.

Microcomputers pose a particular management challenge because of their » dispersion in large numbers throughout Federal agencies. The resulting j problems of data integrity, control, and security can be minimized if they are ] addressed early. j The computing function has two parts: hardware and software. Hardware is a

term which denotes the physical units comprising the microcomputer, i.e. the

electronics, cabinet, keyboards, displays, and printers. The economics of

development and manufacture dictate that hardware be designed to serve a wide

range of applications. The resultant benefit to users is the ability to

purchase a useful computer at a low cost. However, this generality results in

a system which must be subsequently adapted to perform useful functions.

Software refers to computer programs. They consist of a list of

instructions that adapts the computer to a specific application by causing the

hardware to act in a certain manner. Software performs three major functions:

(1) supervising the operation of the hardware, (2) performing computation

tasks for end users, and (3) aiding computer users and prograinners. The first

function is handled by a set of computer programs which are collectively known

as systems software. The second function is handled by application programs.

and programs which handle the third function are called software tools or software development aids .

This report classifies Federal microcomputer users as follows:

Clerical users include typists, junior secretaries, and data entry

personnel. Most clerical uses of microcomputers involve data input

(either numbers or text) formatting, or transcribing. Document

preparation and administrative data entry are the most common

applications of microcomputers.

Administrative users of microcomputers include managers and other Federal

workers whose primary responsibility is related to administrative tasks.

Administrative uses of microcomputers include accounting, budgeting and

planning.

ClerjcaJ.

Administrative

viii
Executive Suiraiery

Professional

Professional users include natural and social scientists, educators,

legal workers, and others working in professional fields. Iheir uses of

microcomputers include data analysis (primarily statistics) and document

preparation.

Technical

Technical users include programmers, engineers, and researchers who

perform their own computer-based system design and programming. The

primary distinction between technical and professional users is the

extent to which they perform their own programming.

The following table lists some user related characteristics that affect

microconputer usage:

CHAE^CTERISTIC CLERICAL ADMINISTRATIVE PROFESSIONAL TECHNICAL

Scope of computer

related tasks

Specialized

Broad Broad Broad

Necessity of

computer-based systems for job

Canputer Background

Relative amount of

systen usage

high Low

Limited Limited

High Low

Low

Variable

Low

Variable

Substantial

High

Tolerance for Low

malfunctions, problems

Low Low Variable

Availability of

personnel for

extensive training

High Low Low Low

Need for subsequent High

support

High Variable Lew

Need for technical

information

Low Low Low High

IX
Executive Summary

Application software transforms a general purpose microcomputer into a systen

for performing useful tasks such as writing a letter or preparing a budget.

The following table shows the most common types of microcomputer application

software

:

APPLICATION

SOFTWARE TYPE

PURPOSE

WORD PROCESSING Creating, editing, and printing documents

DATA MAN^GEJyiENT Organizing, storing, and retrieving data

SPREAD SHEET

PROCESSORS

Performing calculations and formatting for

tabular reports (e.g. budget forecasts)

GRAPHICS

COMMUNICATION

Presentation of data graphs and preparation of

diagrams and illustrations

Data transfer to and from other systems

SPECIALIZED

SOFTWARE

Specialized computation tasks associated with

various job functions (e.g. accounting, statistics)

These applications can work independently, they can also be integrated through

the use of comnon file structures, integrated packages, multitasking operating

systems, or application environments.

In addition to these applications, specialized software exists to perform

tasks such as project management, capital assets management, or electronic

design. In cases where no suitable specialized programs meet the needs of end

users, custom programming is necessary. Users should first consider a data

base management system or spread sheet analyzer before embarking on a software

development effort in a more traditional conputer language.

X
Executive Summary

Although the cost of the microcomputer hardware and software is relatively

low, the cost of effective implementation in a large organization can be much

higher. The system costs start at the time the procuronent is initiated and

continue throughout its life. Major cost components include hardware,

software, procurement, site preparation, instal lation and implementation,

training, supplies, maintenance, and communications.

Microcomputers create two types of risks: technical and organizational.

Technical risks are related to the inability of the system to function

according to expectations — i.e. total failures or inadequate

implementations. Although installation of larger systems also entails some technical risks, microcomputers are unique because they are installed in

settings where expert support is not always readily available.

Organizational risks arise because of the problems in implementing and

managing microcomputers in large organizations. Even if microcomputer

installations are satisfactory from the individual user's point of view, they

can pose a risk to the organization as a whole because of the difficulty of

controlling such systens. In addition, there are concerns over mastering the

new technology and the change in the nature of the centralized computing

function.

Preventing the problems given above requires a recognition of the risks and

explicit actions to reduce or avoid them. Among the actions that an agency

can take are the institution of microcomputer policies, support provisions,

maintenance planning, and development of a training program.

Those considering implementation of microcomputers in their agencies should

consider the following points:

MicroccHtiputer technology is advancing at a rapid rate and new products

are constantly being introduced.

Effective utilization of microcomputers requires continuous support.

Successful implementation of microcomputers requires consideration of a broad range of technological, organizational, ergonomic, and

psychological issues.

The primary focus of control and responsibility for microcOTiputers shifts

from a centralized data processing department (which traditionally

controls larger installations) to individual users.

xi

ABSTEy\.CT

This document is an introduction to microcomputers and their uses in the

Federal government. Basic concepts in microcomputers are discussed, and

their uses by clerical, administrative, professional, and technical Federal

personnel are described. The motivations, costs, and risks of microcomputer

use are identified, and recommendations for successful implementations are

provided. Appendices contain a glossary and annotated bibliography.

KEY WORDS: microcomputer hardware; microcomputer management issues;

microcomputer software; microcomputer technical considerations;

microcomputers.

1
Chapter 1 - Introduction

CHAPTER 1 - INTRODUCTION

The National Bureau of Standards, Institute for Computer Sciences and

Technology (ICST), acting in response to its Brooks Act (Public Law 89-306)

charter, promotes the cost effective selection, acquisition, and utilization

of automated data processing (ADP) resources within Federal agencies. ICST

efforts include research in computer science and technology, direct technical

assistance, and the development of Federal standards for data processing

equipment, practices, and software.

This report describes microcomputers, their uses, and costs. Its objectives

are to introduce microcanputers to readers with a limited background in this

field and to identify issues related to their implementation in Government

agencies.

1.1, MOTIVATION

Figure 1-1 [YOUN82] demonstrates the large and growing importance of

microcomputers. Because of their low cost, microcomputers provide an

opportunity to automate activities in ways that had previously not been

achievable. Some tasks that they perform had previously been assigned to

large computer installations and are being shifted to microcomputers because

of economic reasons or because the user prefers more control over computer

resources. It is therefore not surprising that Federal agencies are

procuring microcomputers in sizable quantities. During an arbitrarily

selected month in 1982, they accounted for 45% of the ADP procurement

announcements in the Commerce Business Daily, and an additional 27% of the

procuronents were for minicomputers whose performance was in the range of

microcomputers

.

Because of their low cost, microcomputers can be procured and installed in

most Federal agencies with much less review and planning than is required for

the purchases of larger computers. However, these installations are

susceptible to a number of problems including:

Limited computer experience among end users

A lower level of experience and capability among microcomputer sales

personnel than among minicomputer and mainframe sales teams

Difficulty of providing pre- and post-installation support

Rapidly changing technology

Incompatibilities among systens in a single organization

2
Chapter 1 - Introduction

1979 81 83 85 87 90

YEAR

Figure 1-1. Projected Growth of Microcomputer Installations [IY0UN82].

3
Chapter 1 - Introduction

1.2. FEDE3^ REGULATIONS AFFECTING MICROCOiyiHJTER PROCUREMENT AND USE

The foundation of Federal ADP procurement regulations is the Brooks Act in

which the Congress recognized the need for Government-wide coordination to

ensure the economic acquisition of canputers and related items. The Brooks

Act requires that Federal agencies wishing to acquire ADP equipment submit a

purchase request to the General Services Administration (GSA) for review and

authorization. The regulations also call for the consolidation of agency

procurements in order to achieve quantity discounts. Above a certain

threshold ($500,000 was the threshold in August, 1983; it is raised as

necessary), the GSA directly participates in the acquisition process.

However, lower cost systems are covered by GSA's Federal Supply Schedule

Program in which contracts are negotiated with commercial firms to provide

supplies and services at stated prices for a given period of time. A

provision in this schedule known as the Maximum Ordering Limitation (MOL -

$50,000 in 1983) authorizes Federal agencies to procure systems directly from

vendors up to the MOL without further negotiations.

Because the Brooks Act did not anticipate the advent of computer systems

costing under $5000, it did not provide a framework for microcomputer

procuranent. Individual agencies have established policies that range from

laissez faire to specification of a named system with extensive justification

and approval required for exceptions. Moreover, any degree of control can be

circumvented by disguising microconputers as laboratory equipment, training

devices, or office machines.

Although microcomputer procurement has evaded centralized control,

microcomputer usage has not. The Privacy Act (1974), the Tax Reform Act

(1976), and the Fair Credit Reporting Act (1974) addressed concerns on the

accuracy, integrity, accountability, and accessibility of information held by

the Federal government in all computers — microcomputers are not exempt. The

Paperwork Reduction Act (1980) dealt with these concerns and also required

justification for the relevance of the information gathered and the efficient

use of the technology. 0MB Circular A71 (1976) addressed concerns on the

misuse and abuse of Government computer systons, and 0MB Circular A123 (1983)

specifically addresses internal controls in Government financial systems. The

overall intention of these laws and regulations is to control how Government

information — particularly that affecting individuals and private

organizations — is gathered, stored, and processed. Microcomputers pose a particular management challenge because of their dispersion in large numbers

throughout Federal agencies. The resulting problems of data integrity,

control, and security can be minimized if they are addressed during the

computer procurement stage.

4
Chapter 1 - Introduction

1.3. CONTENTS OF THIS REPORT

This report introduces microcomputers and discusses their implementation and

use in Federal agencies. The following topics are covered:

Microccmputer Hardware and System Software

Chapter 2 describes microcomputer hardware and system software.

Microcomputer Users

Chapter 3 defines a classification of Federal users consisting of

four categories: clerical (, administrative, professional, and

technical. The chapter describes distinguishing characteristics of

each classification and relates them to desirable microcomputer

features and capabilities.

Microcomputer Applications

Chapter 4 discusses the use of microcomputers by the four user

classes defined in Chapter 3. It also covers issues concerned with

the use of specialized application software and integrated packages.

Management Issues of Microconputers

Chapter 5 identifyies management and usage issues of microcomputers.

It also includes a discussion of the types of microconputer systems

currently available and the appropriate uses.

Glossary of Terms

/^^)endix A contains a glossary of terms related to microcomputing.

Annotated Bibliography

Appendix B contains a list of books and articles written at a nontechnical level on various subjects discussed in this report.

Much of the information of these chapters is presented in tabular form. This

format also shows the relationship among issues and facilitates the

identification of important points. Related Special Reports have been

prepared on the following topics: programming of microcomputer systems

[NBS83a], microcomputer selection [NBS83b], and selecting microconputers for

administrative and managerial users [NBS83c].

5
Chapter 1 - Introduction

1.4. DISCLAIMER AND TRADEMARK IDENTIFICATIONS

Because of the nature of this report, it is necessary to mention seme vendor

names and canmercial products. The presence or absence of a particular trade

name does not imply criticism or endorsement by the National Bureau of

Standards, nor does it imply that the products identified are necessarily the

best available for the purpose.

CP/M is a trademark of Digital Research, Inc. MSDOS is a trademark of

Microsoft, Inc. UNIX is a trademark of American Telephone and Telegraph, Inc.

CP/M and CBASIC are trademarks of Digital Research, Inc. MSDOS, MSPORTRAN,

and Microsoft BASIC are trademarks of Microsoft, Inc. VisiCalc and

iklSolver are trademarks of VisiCorp. Ada is a tradonark of the Department of

Defense.

Finally, the authors wish to emphasize that the technology is rapidly

changing. When this study was initiated in May of 1982, 8-bit computers still

dominated the marketplace. By the time it was completed, microcomputers

capable of executing mainframe software were available. However, issues

related to the nature of the end user communities, the peculiar problems and

possibilities of the highly interactive computing, and the requirements for

computer applications appear to be less volatile. Elnphasis has been placed on

these latter issues, but discussions related to hardware and operating systems

are of necessity more tonporal.

6
CHAPTER 2 - Overview of Microcomputers

CHAPTER 2 - OVERVIEW OF MICROCOMPUTERS

This chapter discusses the function of microcomputer hardware and software

components. Section 2.1 introduces the concepts of hardware and software.

Section 2.2 discusses microcomputer hardware, section 2.3 describes

microcomputer systems software, and section 2.4 introduces programming

languages. Section 2.5 discusses microcomputer conmunication, and section 2.6

concludes this chapter with a description of types of microcomputer systons.

2.1. WHAT IS A MICROCOMPUTER?

A microcomputer is a small and inexpensive computer. To a computer designer,

a microcomputer is a system centered around a microprocessor and associated

circuitry (see section 2.2.9). To computer programmers, a microcomputer is a new type of system for executing programs. Infonnation resources managers may

view microcomputers as the means by which the data processing function is

restructured. To users, microcomputers represent an accessible and convenient

form of computing. Perhaps the only common element in each of these

perspectives is that microcomputers are the most significant development in

data processing to emerge frcm the late 1970s.

The computing function has two parts: hardware and software. Hardware denotes

the physical units comprising the microcomputer, i.e. the electronics,

cabinet, keyboards, displays, and printers. The economics of development and

manufacture dictate that hardware be designed to serve a wide range of

applications. The resultant benefit to users is the ability to purchase a

useful computer at a low cost. However, this generality results in a system

which must be subsequently adapted to perform useful functions.

Software refers to computer programs. These programs contain lists of

instructions that adapt the computer to a specific application by causing the

hardware to act in a certain manner. An example of this adaptation is the

common use of microcomputers as word processing systems even though the

hardware is not specifically intended for that application. The term

"software" originates from the notion that computer programs are easier to

change than the hardware.

Software performs three major functions: (1) supervising the operation of the

hardware, (2) performing computation tasks for end users, and (3) aiding

computer users and programmers. The first function is handled by a set of

computer programs which are collectively known as systems software. The

second function is handled by application programs, and programs which handle

the third function are called software tools or software development aids . Systems software is discussed in section 2.3, and application software is

described in chapter 4, and software development aids are introduced in

section 2.4.

2.2. MICROCOMPUTER HARDWARE

Figure 2-1 shows the components which comprise computer hardware and table 2-1

briefly describes their functions. Sections 2.2.1 through 2.2.8 discuss the

7
CHAPTER 2 - Overview of Microcomputers

individual components and section 2.2.9 provides a brief overview of the

technology used in these canponents.

r

Video

Display Screen

1

Keyboard

Disk Drive Printer

Figure 2-1. Microcomputer Hardware Devices

8
CHAPTER 2 - Overview of Microcomputers

TABLE 2-1. MAJOR MICROCOMPUTER HARDWARE COMPONENTS

COMPONENT

PROCESSING/MEMORY UNIT

DISK DRIVE

KEYBOARD

VIDEO DISPLAY SCREEN

(or CRT)

PRINTER

MODEM

DESCRIPTION

Contains the central processing unit,

memory, and circuitry for transferring data

to and from the memory

Storage of data when not being manipulated

by the computer. Other devices which may be

used for the same purpose include magnetic

tape, bubble memory, or optical disks.

A typewriter-like arrangement of keys used

for entering letters, numbers, and other

information into the computer.

A television picture tube-like unit which

displays information generated by the

computer.

Puts information on paper.

Sends and receives data transmissions to

and from other systems over telephone

lines. Other means of computer

communication which send signals through

different types of cables (e.g. coaxial or fiber optics) are also available.

9
CHAPTER 2 - Overview of MicrocxDmputers

2.2.1. Processing and Memory

The heart of the microcomputer is the central processing unit (CPU), which is

also referred to as a microprocessor (a microcomputer consists of the CPU,

memory, and interfaces to peripheral devices). Most microcomputers are

based on the microprocessors shown in table 2-2. The utilization of

comparatively few CPUs has contributed to industry-wide standardization and

the resultant wide acceptance of microcomputers. The most canmon descriptor

of microprocessors is the number of "bits" (an acronym for binary digit, the

smallest unit of information) that may be operated upon at one time. The

first microprocessors operated on 4 bits in parallel; current microprocessors

operate on 8, 16, or 32 bits.

CPUs that work with a large number of bits have three advantages over those

that work with a smaller number: they process information faster, they have

more instructions (i.e. they can do more), and they can access much larger

amounts of memory. As a result, they can execute more sophisticated software

and manipulate larger amounts of data.

The computer memory contains the program (i.e. the list of instructions) which

the central processing unit executes. There are two types of memory, readonly and randan access. Read only memory (ROM) is programmed at the factory

and can not be written into by the user, i.e. it is permanent. ROM is useful

for frequently executed programs that do not change. At least a portion of

most operating systems is furnished as ROM. Many systems also include a

common language processor such as a BASIC interpreter (discussed in section

2.4) in read only memory.

Unlike ROM, most random access memory (RAM) is volatile , i.e. when the

computer power is turned off, its contents disappear. A benefit of the

impermanence of RAM is that the function of the microcomputer may be changed

by reading a new program into random access memory. By changing programs,

the same hardware may be used for diverse tasks such as word processing or planning departmental budgets. Changing programs in read-only memory requires

replacing the memory chips which are usually packaged in a "cartridge." This

technique is used with some small portable microcomputers and pocket

calculators.

Both RAM and ROM store bits in groups of eight bits called "bytes". Each byte

may be used to store an encoded character such as a letter of the alphabet.

The code for alphabetic and other characters has been standardized by the

American National Standards Institute as the American Standard Code for

Information Interchange (ASCII) and has been adopted by all microcomputer

manufacturers.

Memory capacities are measured in kilobytes (abbreviated as Kbytes or "K").

Kilobytes are defined as having 1,024 bytes rather than 1,000 bytes because

microcomputers use binary arithmetic and 1,024 is an integer power of two. For

the applications in this report, microcomputer memories range from 64 to over

1,000K, and the trend is to larger memories as prices fall and more memory

circuits are placed on a single integrated circuit (or "chip", see section

2.2.9)

.

10
CHAPTER 2 - Overview of Microcomputers

TABLE 2-2. COMMDN MICROPROCESSORS

NO. OF BITS MANUFACTURER DESIGNATION

16

32

Intel

Zilog

Mostek

Intel

Motorola

Zilog

National Semiconductor

Hewlett Packard

AT&T

Intel

Motorola

National Semiconductor

Zilog

8080, 8085

Z80

6502

8086, 8088,

iAPX 186, 286

68000

Z8001, Z8002

16032, 16008

[undesignated]

BellMAC 32

iAPX 432, 386

68020

32032, 32132

Z80,000

11
Chapter 2 - Overview of Microconputers

2.2.2. Mass Storage

Mass storage devices including magnetic disks, tape, and bubble memory provide

non-volatile storage which can be changed by the user (as opposed to ROM,

which can not be easily altered). Because of the relatively slow access time

on mass storage devices, data must be transferred to RAM before being used by

the CPU. Therefore, mass storage is sometimes referred to as "external"

storage in contrast to the "internal" storage provided by ROM or RAM.

Magnetic Disks

Magnetic disks are the most widely used form of mass storage because

they allow relatively rapid access to any location on the disk. Three

important factors affecting performance are:

Access time: the time necessary to reach a designated location

on a disk (analogous to the movement of a phonograph needle to a

point on a record).

Data transfer rate: the rate at which data can be transferred from

the disk to RAM and back.

Capacity: the amount of data which can be stored on a disk. In

general, large disk capacities are desirable.

Two types of disk storage units are currently available: "floppy" or flexible disks and "hard" or rigid disks. Floppy disks are generally

less expensive but have lower performance than hard disks. Table 2-3

describes the various diameters and capacities of current floppy disks.

The most common rigid disk diameters are 8" and 5.25" ; the latter

diameter is apparently emerging as the dominant choice of system

manufacturers [KILL83, MILL83, DOHE83, JOHN83]. The capacity of 5.25"

rigid drives is 10 to 20 Mbytes in current microcomputers, and current

advances in storage technology make it probable that these capacities

will increase many-fold. Some manufacturers offer drives which hold

several disks with a resultant doubling or tripling of the storage

capacity per drive. With most hard disks, the storage media are not

removable from the drive. Thus, data backup (i.e. creation of duplicate

copies of the data on an alternate storage device in the event of a disk

failure) and off-line storage (i.e. placing the disk contents on a magnetic tape, floppy disk, or other medium which may be physically

removed and stored) is desirable.

Magnetic Tape

Although magnetic tape was initially used as a data storage medium for

microcomputers, the superior performance of disk drives has resulted in

its being displaced as a primary mass storage medium in most systems.

However, specially designed magnetic tape cartridge units are currently

used to back up hard disks.

12
CHAPTER 2 - Overview of Microcomputers

TABLE 2-3. FLOPPY DISKS

DIAMETER CURRENT DATA CAPACITY*

8" 241 Kbytes - 1.6 Mbytes

5.25" 160 Kbytes - 2 Mbytes

COMMENTS

First introduced by IBM in 1970

for larger systems; low storage

capacity data format is quite

popular and is a ready means of

exchanging data and programs with

other systems.

Introduced by Shugart in 1976;

became more popular than 8"

drives because of smaller size.

There are many different formats

for 5.25" drives; thus,

exchanging programs and data is

often difficult.

Sub - 5" 125 Kbytes - 0.5 Mbytes Sub-5" drives have the potential

of offering shorter access times,

higher transfer rates, and higher

densities in smaller and more

reliable units. However, at

present, 5 different proposed

standard formats in 4 different

disk diameters and several

alternative packaging techniques

exist. None has yet emerged as

dominant.

* Capacities of commercially available units as of mid-1983; capacities as high as 10 Mbytes have been announced for floppy disks using vertical magnetic

storage technology [KILIj83] .

13
Chapter 2 - Overview of Microcanputers

Other Technologies

Additional mass storage technologies are constantly emerging. Magnetic

bubble momory is useful for mass storage in specialized applications

where high reliability or low weight are considerations- Its

disadvantages are higher cost and limited capacity. Optical disks may be

useful for storing large amounts of permanent data, but the technology is

still relatively new, and additional work on the basic technology,

hardware interfaces, and syston software is necessary for these devices

to becane practical for conmon applications.

2.2.3. Keyboards

Keyboards are the most conmon input device for curroit microcomputers and may

be either an integral part of the case holding the video display or detached.

In addition to the letters, numbers, punctuation, and special symbols

typically found on typewriter keyboards, some microcomputer keyboards have

special function keys. These keys allow the user to manipulate the display,

memory, programs, or peripheral devices. Numeric keypads (i.e. those

resembling adding machine keyboards) and cursor control keys (see section

2.2.5) are also found on many microcomputers keyboards,

2.2.4. Other Input Devices

Keyboards may be supplonented by other input devices including pointing

devices, digital to analog converters, and voice input.

Pointing devices enhance operator convenience in such operations as making a

choice from a list of options or indicating data to be acted on (e.g.

designating a paragraph to be deleted from a document) and for performing

graphics operations. Table 2-4 lists pointing devices which are commonly used

for microconputers.

Analog to digital conversion is useful in situations where temperature sensors

(e.g. thermocouples or thermistors), pressure sensors (e.g. transducers),

radiation detectors, or other devices may be the source of the input. In

these cases, continuously variable analog voltages from instruments are

converted to discrete digital form and read into the computer's monory.

Voice input devices are also available. The voice may either be recorded for

subsequent playback or it may be analyzed by the computer in an attempt to

recognize the word or sound. Unfortunately, the storage capacity of current

microconputers is too limited for lengthy messages, and systons that analyze

and discriminate words have limited vocabularies and problems differentiating

speech fron ambient noise.

14
CHAPTER 2 - Overview of Micrcx:omputers

TABLE 2-4. C01^M)N P0INTIN3 DEVICES

DEVICE DESCRIPTION

Mouse The mouse is a small, hand held device which, when

moved across a flat surface, causes a corresponding

signal to be sent to the conputer. The motion of the

mouse may be detected using either an optical or mechanical system.

Light pen The light pen is a pen-like device which detects

changing light as it appears on a CRT screen (section

2,2.5) and generates a signal when this occurs. The

time at which this signal is generated can be

translated to a corresponding position through a part of the system software. The primary advantage

of light pens is that the operator can rapidly move

them to any point on the CRT, A disadvantage is that

the operator must lean forward and touch the screen,

an activity which can result in fatigue if performed

frequently.

Joystick The joystick is a finger-sized (or smaller) device

which sticks out from the plane of the table or keyboard. It is connected to movement generators

which send both horizontal and vertical signals to

the computer depending on how it is manipulated by

the operator. Although higher precision models are

commonly used for computer aided design and drafting

on larger computers, joysticks designed for

microcomputers are typically low cost and low

precision input devices which may not be suitable for

many applications.

Digitizing tablet A digitizing tablet is a special surface which may

vary from the approximate size of an index card to

that of a large drawing. This surface can sense

movement of a stylus (or similar device) and transmit

the data to the conputer for subsequent processing.

15
CHAPTER 2 - Overview of Microcomputers

2.2.5. Video Display Monitors

Video display monitors, also referred to as video display tubes (VDTs) or

video display units (VDUs), are the most common output devices on current

microcomputers. Because nearly all use cathode ray tubes similar to

television sets, they are often referred to as CRT terminals or simply CRTs.

Low-end microcomputers use television sets, but the display quality (i.e. the

clarity with which characters are displayed) is generally poor. Such systems

are not of interest for the applications covered in this report. Displays

that are of interest may be characterized as follows:

Color QL Monochrome

Typical color monitors can display from 8 to 265 different colors.

Variations in color may be used for aesthetic value or to enhance the

amount of information on the display (for instance showing negative

numbers in red). Color displays are generally more expensive than

monochrome displays and require more memory, either in the display unit

itself or in the conputer.

Mcoochrome displays have only a single, light foreground color, usually

white, green, or amber. Some displays show dark characters on light

backgrounds. The question of which combinations are best from the

operator point of view is being studied, but there are no currently

generally accepted conclusions [KETC82].

Character Oriented o£ Bit-Mapped

As shown in figure 2-2, characters are made up of discrete dots. To

form a given character, certain dots in a matrix of possible dots are

illuminated while others are not. A character oriented display can show

only certain pre-defined patterns of dots which make up the 96 characters

specified by by the American National Standards Institute (ANSI), and up

to 128 additional characters. These additional characters may be used

for foreign alphabets, geometric characters, and other special syirtols,

but they are not standardized and vary from manufacturer to manufacturer.

Character oriented displays typically have a capacity of 24 or 25 eightycharacter lines.

With a bit-mapped display, any dot can be turned on or off. This

capability allows the creation of graphics, non-Latin characters, and

many other features which are under control of software. Although bit

mapped displays offer greater flexibility, they are more expensive and

require more hardware and systen software support than character oriented

displays.

Whether a bit-mapped or character oriented display is used, the quality

of the displayed characters depends on the number of dots making up each

letter or number. There are significant legibility (and resultant eye

strain) differences between characters made up of dots on a 9 by 14

matrix and a 6 by 9 matrix.

16
FIGURE 2-2. ASCM Characters displayed as a series of dots

(from [IBM81] p. 3-17)

17
chapter 2 - Overview of Microcanputers

Memory-mapped and Serial Displays

A memory-mapped CRT displays whatever is placed in a certain portion of

the computer's memory. This method facilitates the rapid change of the

display, but requires additional memory and specialized interface

hardv^are. Serial displays receive characters one at a time, and display

then as they are received. Although this technique is slower and may not

be suitable for graphics (up to 20 minutes may be necessary to fill a

medium resolution — i.e. 600 x 600 — screen [DOIESSb]), it enables the

manufacturer to use standard interface hardware and widely available

CRT/keyboard units.

Flat Displays

The increased interest in portable computers has spurred the development

of flat displays which do not use bulky cathode ray tubes. Currently,

the most common types of flat displays use liquid crystals similar to

those used in calculators and digital watches. These displays are

generally small (from 40 to 320 characters) and difficult to read in

dim light. Another type of flat display uses an array of tiny plasmafilled light bulbs which act as dots that can display characters and

graphics in the same manner as CRTs. However, these plasma displays are more expensive than liquid crystal displays and require additional

power, a problon in portable units.

2.2.6. Printers

Printers vary in many characteristics including paper dimensions, printing

speed, printing methodology, quality, paper-handling, size, and noise levels.

The methods for interfacing printers to the canputers are also quite variable.

Speed and Throughput

Microcomputer printers generally print a single character at a time, and

their speeds are rated in characters per second. Throughput, which may

be as little as 1/3 of the character per second rating [PRES83], is based

on the number of pages per unit time that can be printed. Throughput is

a more realistic measure of productivity but can not be measured as

easily as printing speed. Differences between throughput and printing

speed can be due to the paper feed and print head positioning mechanisms

or to the "intelligence" of the printer (i.e. not moving the print head

to an area of blanks).

Printing Process

Mechanical or "impact" printers form characters by striking an inked

ribbon against paper. Fully formed character printers strike a formed

character, like a typewriter. Dot matrix printers make up a letter in

the same manner as a CRT display. The fully formed-character printers

(which are also referred to as letter quality printers) are generally

slower and more expensive, but they produce higher quality output than

dot matrix printers.

18
CHAPTER 2 - Overview of Microcomputers

Most dot matrix printers work by striking pins against a ribbon. Some

have multiple colors. These printers are nearly always faster than the

fastest fully formed-character printers, but the dots making up a character are noticeable. Quality improvements in dot matrix printing

include the use of more dots per character and the staggering of dots on

a second pass. As was the case with bit-mapped CRTs, some printers are

capable of printing individual dots, and graphics or custom type fonts

can be drawn.

Nonmechanical printing processes include thermal and electrostatic

techniques. These techniques are often used in small special purpose

printers and may require treated papers [FOST83]. Newer techniques

include ink jet printing and laser printing. Although promising, they do

not yet provide the same quality as fully formed impact printing for a given cost.

Precision Positioning Control

Precision positioning control is the ability to position the printhead

(the part of the printer which actually produces the character on the

paper) at any point on the page with high precision (typically 1/120 " horizontal and 1/48 " vertical). This capability, when combined with the

appropriate driver software in either the printer or the CPU allows the

following features:

Variable pitch printing (i.e. the ability to print an "M" which is

wider than an "1" and adjust the horizontal position of the

printhead accordingly)

Proportional spacing or microjustification (i.e. the ability to vary

the amount of space between characters for right justification)

Boldface printing (i.e. overstriking the same character with a slight offset to make it appear wider and darker)

Superscripts and subscripts

High quality graphics (see figure 4.7)

Paper Handling

Two common techniques of paper handling are used in printers: friction

feed or traction feed. Friction feed uses a typewriter-like pressure

platen to feed the paper through the machine. Traction feed uses two

star-shaped wheels and pin holes in the side of the paper. Friction feed

is useful for individual sheets and paper without the holes necessary for

tractor feed (e.g. typical office stationery). Traction feed is useful

for continuous printing involving a large number of sheets.

The most common types of printers will handle 8 1/2 inch wide sheets;

printers handling sheets of up to 14 inches wide are also available.

19
CHAPTER 2 - Overview of Microcomputers

Noise

Noise is an inevitable result of the mechanical nature of some printing

processes. Dot-matrix printers are often quieter than fully formed

character printers. Nonmechanical printing processes including thermal,

chemical, ink jet, and laser printers are generally even quieter, but

noise from fans or other auxiliary systens may cause problems.

Reliability

Because printers are made up of many mechanical parts, their reliability

and maintainability may be a source of problems. Non- impact printers

(i.e. thermal, electrostatic, or chemical printers) have fewer moving

parts and thus have fewer breakdowns. Other non-mechanical printing

technologies, for example ink-jet or laser printing are still relatively

new, and not all performance and reliability problems have been

solved in lower cost units.

Compatibility

Most current printers use internal microcomputers to control the printing

process. These microcanputers are responsible for the "intelligence" of

the printhead positioning mechanisms, the capability for producing

graphics, and many other printing functions. Many of the functions

performed by these printer microprocessors are under software control of

the main CPU, and software compatibility must exist. The need for such

compatibility can complicate the interfacing of a printer to a microcomputer. Thus, users should not assume that any printer will work

with any microcomputer — even if they both nominally follow the same

standards for hardware interfaces and ASCII character sets.

2.2.7. Other Types of Output Devices

Additional types of output devices include plotters, digital to analog

converters, and voice ouput.

Plotters are used for graphical output, and are available at low cost. In

these devices, a pen is moved on the surface of a sheet of paper in order to

draw graphs. Color graphs can be produced by plotters with multiple pens

which contain different color inks. Plotters are useful in managerial,

scientific, and technical applications.

Analog output is necessary for specialized laboratory or process control

applications. Digital to analog converters (DACs) convert digital data

(typically represented as 8, 12, or 16 bits) into a voltage level which can be

amplified or otherwise manipulated externally.

Two general types of voice output devices are available: recorded vocabulary

machines and voice synthesizers. Recorded vocabulary devices store a digital

representation of a pre-recorded message and play it back without further

processing. Two techniques are used for voice synthesis: one uses a

mathem.atical formula to create a signal which simulates speech based on

parameters stored in memory and the second uses a set of stored primitive

20
CHAPTER 2 - Overview of Microcoinputers

sounds ("piionemes") to assenible words. These voice synthesizers usually have

their cwn microprocessors, and are progranmed to accept standard characters

(such as would be printed or displayed) and convert them to the appropriate

phonemes for pronunciation. They are more flexible than the recordedvocabulary machines, but less intelligible.

2.2.8. Ccrmunication Hardware

Hardware necessary to support COTimunication can range from a sinple cable to

connect two serial or parallel interfaces (discussed in the next secticai) to

coii^)lex circuitry involving data flow control, error detection and correction,

and communication routing.

If the two systems are nearby each other (i.e. in the same room), then it is

frequently possible to connect their output ports (see section 2.2.9) by means

of a cable. Because it is often necessary to cross connect pins, the

operation should be performed by someone who is technically qualified.

If the computers are to be connected over longer distances, modems can be

utilized. Modons are devices which convert computer output to an analog

signal for transmission over telephone lines (and also convert the analog

signal to a digital signal at the receiving end). The range of options

available on modems is quite large: sinple units do little more than perform

the digital to analog signal conversion; more "intelligent" units can

automatically dial numbers, store messages for delayed transmission, and a number of other functions.

Specialized communication interfaces are necessary if the con^ters are to be

connected to local area networks or other systems which use synchronous

transmission or advanced communication protocols. A more detailed discussion

of these topics is presented in section k . 5.

2.2.9. Microcomputers at the c:oc:iponent Level

Each of the devices described in the previous sections are made up of

a number of differait coir^onents. While most ccxr^ter users need not concern

themselves with the internal structure of the hardware, knowledge of some of

the names and purposes of these parts may prove useful. Nearly all digital

devices contain the following elements:

Integ]:ate<3 Circuits

Information processing is carried out in small electronic parts called

integrated circuits (ICs). Advances in microcomputers are a result of

increasing the number of functions that can be placed on a single

integrated circuit. In the course of the last decade, ICs have moved

from medium scale integration (MSI — hundreds of transistors per IC)

through large scale integrated circuits (LSI — thousands of transistors

per IC) to very large scale integrated circuits (VLSI — tens of

thousands of transistors per IC). A single VLSI circuit can provide

functions formerly found only in larger computers in a form that is

inexpensive, reliable, and rugged. Some of the common types of

integrated circuit are briefly described in table 2-5. However, several

21
Chapter 2 - Overview of Microcomputers

of the functions described in the table are frequently found on a single

IC Figure 2-3 is a drawing of an IC and a socket (explained in the next

paragraph)

.

Printed Circuit Boards

Integrated circuits are mounted on epoxy resin (i.e. plastic) cards and

are connected to each other by pathways of copper bonded to the plastic

surface of these cards. These cards are called printed circuit boards.

The ICS may be soldered directly onto the boards or placed in sockets.

Boards containing socketed ICs are more easily serviced, but are also

more prone to failure and more expensive. Printed Circuit boards

containing RAM ICs are frequently socketed to facilitate replacement of

failed units. Figure 2-4 is a drawing of a printed circuit board.

Internal Microcomputer Buses

A microcomputer bms is a set of conductors which interconnects various

functional groupings (e.g. memory, disk interfaces, CPU, etc.).

Typically, a microcomputer bus consists of power, timing, data, address,

and control lines. Many microcomputers are composed of a number of

circuit boards which serve distinct functions (e,g, memory, disk drive

control, CRT control, etc). This design provides manufacturers and end

users with more flexibility to meet individual requironents. If the bus

design has been published and well documented (i,e. physical dimensions,

electrical characteristics, line assignments, communications protocols,

and timing are all specified), then third party vendors can supply

additional boards which further enhance the functionality of the

microcomputer. The Institute of Electrical and Electronic Engineers

(IEEE) has published two standards for two buses: IEEE Std 696 (based on

the MITS S-100 bus) and IEEE Std 796 (based on the Intel Multibus),

i^lications such as laboratory or field data collection may require the

use of these standard buses for the connection of specialized devices.

Standards for other microcomputer buses are currently being developed.

Published specifications for the IBM PC and Apple II buses are also

available, although these are not formal standards.

22
CHAPTER 2 - Introduction to Microccmputers

Figure 2-3. Integrated Circuit and Socket (from [IBM81] p. 3-117)

Figure 2-4. Printed Circuit Board (from [IBM81] p. 5-41)

23
CHAPTER 2 - Overview of MicroccMputers

TABLE 2-5. TYPES OF INTEGRATED CIRCUITS

CIRCUIT TYPE PURPOSE

Microprocessor

(CPU)

Coprocessor

Functions as central processing unit of computer.

Fetches data and instructions from memory, operates on

data, and stores data back in memory.

A specialized microprocessor that is activated by the CPU

for specialized operations such as mathematical

calculations.

Randan Access

Memory (RAM)

Memory Management

Unit (MMU)

Direct Monory

Access Controller

Interrupt

Controller

UART or USART

Modem

D/A Converter

(DAC)

A/D Converter

(ADC)

Contains electrical circuit elements which store binary

data as the presence or absence of an electric voltage.

Canmon RAM integrated circuits contain between 16,000 and

256,000 of these elements.

Partitions and controls memory areas for more rapid

access, protection of critical areas, multitasking

syStOTIS,

Directs data transfers between disks and blocks of memory

without the need for CPU intervention

.

Interrupts the CPU (while it is performing another

task, directs it to a specific set of instructions, and

saves the results of the interrupted task to enable the

CPU to continue processing when it finishes servicing the

interrupt. Use of an interrupt controller enables the CPU

to perform several different tasks simultaneously (e.g.

printing one document while editing another).

Universal (Synchronous/) Asynchronous Receiver

Transmitter. Controls transfer of data fran the computer

to an RS-232 or other type of serial port. Keeps track of

timing, and status lines.

Modulator/Demodulator. A device which connects the

microcomputer to a telephone, teletype, or intercom line.

Digital to Analog Converter. Converts the digital output

of the microcomputer into an analog signal (typically a

voltage)

Analog to Digital Converter. Converts an analog signal

from a sensor (e.g. thermocouple or transducer) to a digital signal which can be processed by a microcomputer.

24
Chapter 2 - Overview of Microcomputers

I/O Interfaces

Standardization is also necessary for the connection of peripiierals (e.g.

printers, plotters, COTmunication lines, etc.) to the microcomputer. The

most formal standard for this type of interface is a parallel connection

which has been designated as IEEE Std 488. Unfortunately, two less

standardized interfaces are far more common: the R9-232C interface is

used for serial connections and the Centronics printer interface (named

after a printer manufacturer which originated it) for parallel

connections. Thus, end users should not depend on designations like

"RS-232C" compatible as the assurance that devices from different

manufacturers will function correctly when connected.

2.3. SYSTEMS SOFTWARE

Systems software consists of two parts: the operating system and utility

programs. The operating system supervises the operation of the computer

including control of perijiierals and execution of programs. A very important

function of the operating system is the transfer of data between the disk (or

other mass storage device — see section 2.2.2) and RAM; operating systems are

sometimes referred to as disk operating systems or simply "DOS" for this

reason. Utility programs enable the user to perform functions such as the

routing of data and manipulation of files. Together, the operating systen and

the accompanying utilities form the software "backbone" of the computer.

Table 2-6 describes the coirmon functions of operating systons and associated

utilities in more detail, and table 2-7 lists commonly available types of

microcomputer operating systems.

Systems software is generally purchased with the microcomputer hardware, and

all or parts may be stored in ROM. Many microcomputer manufacturers offer

several different operating systems for their hardware, and independent

software companies may sell their operating system for a given microcomputer,

independent of the hardware manufacturer.

Two issues related to operating systems are important to microcomputers:

compatibility with application software and the user interface.

CQinpatlbiXity with Application Software

Operating systems are the "plug" into which the application software must

fit in order to run on a microcomputer. In other words, application

programs are written to be compatible with a specific operating system.

Thus, the most important characteristic of an operating system is the

availability of software pertinent to the intended use. Communities

which include thousands of programs and vendors, magazines, users groups

and clubs, conventions, books, and experts have been established for

dominant operating systans.

For 8-bit machines, the CP/M operating system has predaninated because

hundreds of hardware manufacturers have adopted it. MSDOS, an operating

system with design roots in CP/M, has become dominant in lower

performance 16-bit systems. UNIX, an operating system that was developed

25
Chapter 2 - Overview of Microcomputers

TABLE 2-6. GENERAL FUNCTIONS OF SYSTEMS SOFTWARE

FUNCTION RELEVANCE DESCRIPTIOQ

Memory and All Users Allocates system resources such as memory space.

Resource disk files, and I/O devices. Allcws application

Mamgement software to access these resources.

Input and All Users Controls peripherals that are attached to the

Output system (e.g. CRT, printers, plotters, etc.).

Some operating systems also permit I/O

redirection, i.e. the routing of data meant for

one peripheral (e.g. printer) to another (e.g.

disk)

.

Directory All Users Maintenance of a list of file names, their

Maintenance location on the disk, size, protection state

(e.g. read/write, read only, copy protected) and

creation/last access date. Special features

include hierarchical directories (useful for

hard disks where hundreds of files need to be

subdivided into groups), duplicate directories

(a feature which enables the disk to be used

even if the information in one directory is

damaged), and hashed directories (an abbreviated

portion of the directory is kept in RAM to

facilitate faster disk access).

Utilities All Users Software which enables the user to copy,

delete, rename, and compare files, to redirect

I/O and reconfigure devices, to set time and

date values, to display the status of various

systen units and resources, to format disks and

generate new copies of the operating system.

Popular operating systems are roughly comparable

in these tasks; however, some might be more

suitable for less knowledgeable users than

others.

Ccmmand All Users Each operating system provides a means by which

Processing the user executes programs (intrinsic or

application-oriented). Both menu- and commandoriented systems are found on personal

computers. Some menu-oriented systems use a

mouse for selection rather than the keyboard.

Most operating systems have provision for

executing a series of programs or commands when

the systems are started up or when the user

types in a single command.

26
Chapter 2 ~ Overview of Microcomputers

TABLE 2-6 (continued) . GENERAL FUNCTIONS OF SYSTEMS SOFTWARE

FUNCTION RELEVANCE DESCRIPTION

Software

Tools

(or

Software

Development

Aic3s)

Programmer

Services

Programmers Software tools are programs which simplify the

development of other software. A variety of

tools are supplied with or can be purchased for

development of software under any given

operating systan. These include assemblers and

compilers, debugging monitors, disassemblers,

cross-reference generators, program editors

(some have syntax checking capabilities) and

formatters (some have the ability to detect

levels of nesting, beginnings and endings of

blocks, and other structures which are indented

or paginated accordingly), linkers, and file

management utilities. Additional tools such as index management packages and form generators

are generally offered from third parties.

Programmers Programmer services are related to software

developnent tools but are an integral part of

the operating systen. These services typically

include communication between concurrent

processes, specialized support for screenoriented I/O (e.g. cursor positioning, double

intensity and reverse video, protected fields,

etc.), graphic output, and support for menus

(i.e. generation of menus and responding to user

selection). These more sophisticated services

may eventually result in superior user

interfaces for both the operating system and

application software. They may also enhance

portability, particularly if a complement of

standard or near standard services is

established.

27
Chapter 2 ~ Overview of Microcomputers

TABLE 2-7. CjONFIGURATIONS OF OPERATING SYSTEMS

CONFIGURATION EXAMPLES COMMENTS

Single user/

single

tasking

CP/M-80

CP/M-86

MSDOS (1,2)

p-System

Single user/single tasking operating

systems are the simplest and most common

(as of 1983) operating systems. The cited

examples have a large variety of

application software, wide distribution,

and support from a variety of sources.

Although more powerful hardware and larger

memory sizes are making more sop^histicated

operating systems feasible on

microcomputers, single tasking operating

systens will still be prominent on portable

systems (because of limitations on memory

and power consumption) and lower cost

units.

Single user/

multitasking

Concurrent

CP/M-86

MSDOS (3.0

and above)

Multiuser UNIX

(and variants)

MP/M

Turbodos

Single user/multitasking operating systans

were first introduced in 1983 and are

becoming more popular on 16-bit (and

higher) systems with larger amounts of

memory (typically greater than 256K).

Advantages include rapid switching between

tasks and the concurrent execution of tasks

that use dissimilar resources. The

techniques for multitasking are well

understood from the mainframe world. Its

use in microconputers allows a user to work

with several tasks (e.g. communications,

printing a job, and running a spread sheet)

simultaneously. Major software development

organizations are making a large investment

in programmer development aids and

graphically-oriented user interfaces for

this class of system, and increasingly

elaborate products will probably arise in

the near future.

Multiuser/multitasking systems allow

several users to access the same resources

simultaneously, and their primary advantage

is to facilitate several users' access to

common data. They are feasible for 16 -bit

microcomputers with large memories (512 K

or above) and for multiprocessor systems

(i.e. each user has a dedicated

microprocessor which shares common system

resources). Sane systems were written to be

compatible with earlier single tasking

systems to allow use of existing software.

28
Chapter 2 - Overview of Microcomputers

for larger computers, is now becoming popular for more powerful 16HDit

and 32-bit microconputers. Well over a dozen conpanies have implemented

versions of it for 16 bit machines. Many microcomputer manufacturers

offer several operating systems for their hardware, and application

software companies have versions of their programs for more than one

operating system.

Unfortunately, having the appropriate operating system is a necessary but

not always sufficient condition for insuring that an application program

will work with a given microcomputer. Use of special hardware features

{e.g. bit mapping on a CRT or a dot matrix printer — see section 2.2)

my require special software modifications which must be performed by

experts.

l-he Operating System User Interface

Interaction with the operating system occurs prior to executing

application programs or after completing the task, when running

utilities, and when changing the configuration of the computer (e.g.

adding more memory or a new peripheral). Thus, the quality of the user interface (see section 2.5) affects all users — even those who intend to

do nothing more than execute a particular application progranu

Because earlier operating systems such as CP/M, MSDOS, or UNIX were

constrained by available memory and allowable processing overhead (i.e.

the amount of time spent executing the operating systen rather than the

application), they provided only minimal user interface features.

However, the advent of more powerful 16-bit processors, inexpensive

memory, and numerous users without formal computer training encouraged a change in this situation. In 1983 several companies introduced operating

systems with much more sophisticated interfaces [PETE83, W(X)D83, LEMM83,

HAYH83]. Commands may be entered through either the keyboard or by

pointing to an option displayed on the screen with a device such as a mouse (see section 2.2.4). These operating systems also provide

assistance through the use of help screens and easy transitions among

tasks.

Whether these newer operating systems supersede the earlier offerings

depends on acceptance by independent application software developers,

end-users, and microcomputer manufacturers. Independent software

developers will accept the systems if they can develop sophisticated user interfaces through the operating systons and the training, seminars, and

technical literature provided by the operating systems vendors.

Acceptance by end users depends on the availability of application

software, price of both the operating system and application software,

and the quality of the operating system interface (e.g. menus, on-line

help files, support for point devices, ease of learning, convenience).

Microcomputer manufacturers will adapt their hardware to software which

gains widespread market acceptance (as defined by the number of

purchases)

.

29
Chapter 2 - Overview of Microcomputers

2.4. PROGRAMMING LANGUAGES

This section describes how software is developed and introduces the concept of

programming languages. Computer programs are a sequence of instructions which

the central processing unit (CPU) executes. These instructions may cause the

CPU to fetch data from the memory, perform arithmetic operations, accept

input, or send data to a perij^eral device. These instructions are stored in

the computer memory as a series of Is and Os, a form referred to as machine

language or object code. Because machine language is difficult for people to

work with and understand, language processors have been developed that accept

instructions in a more usable form and translate than into machine language.

As computer programming evolved over the past four decades, the following

types of languages have evolved:

Assembly Language

Assembly language is a straightforward transformation of the machine

language into a series of acronyms which help the programmer understand

the nature of the commands. For example, a command which increments a number by 1 is represented as 00000100 in machine language but as INR in

assembly language; a command telling the processor to move to a different

area of memory for the next instruction ("Junp" to a different location)

is represented as 1100011 in machine language and JMP in assembly

language. An assembler is a program which converts assembly language

into machine language. Assemblers have undergone a number of

enhancements. The more sophisticated assemblers are referred to as

"macroassemblers"

,

High Order Languages

High Order Languages (abbreviated as HOLs or HLLs — High Level

Languages) were first developed to aid scientists and engineers to

perform calculations with a set of commands that was meaningful to them

rather than in a language that could be processed by the CPU. Figure 2-5

demonstrates the purpose of high order languages. Both code fragments

(these are not freestanding programs) represent the same process:

integer division (the assembly language routine is restricted to 8-bit

numbers, i.e. those less than 255). Figure 2-5 shows that unlike

assembly language, there is no directly corresponding machine code for a high order language statonent. Thus, a much more sophisticated process

is necessary for translation of an HOL statement into a machineexecutable form.

Two general approaches have been taken to perform this process:

compiling and interpreting.

Compilers analyze HOL statements, decide (through a rather complex

process) on the appropriate set of assembly language statements, and

write these statements to a file. This file is then assembled into

machine language. Some compilers perform the translation in several

stages (called "passes"), and more sophisticated compilers have the

ability to analyze the machine code generated by a first-pass conpilation

30
Chapter 2 - Overview of Microcanputers

8080 ASSEMBLY LaiEHIAGE

MVI

MVI

E,DIVDND

D,DIVSR

CXDMMENTS OCCUR AFTER SEMICOLON

Store the dividend (defined elsewhere) in register E

store the divisor in register D

because 8080 registers are cxily 8 bits wide

both t, and D must be integers less than 256

(other code here including invocation of subroutine DIV)

DIV: DIV is label (i.e. address) of the division subroutine

LXI B,9 J load register B (a counter) with the number 9

NXT: mj A,E ; move the divisor (register E) to the accumulator

RAL ; rotate the most significant bit of A to the carry

MOV E,A ;

• save the dividend back in register E

DCR B J

• decronent the counter in register B

RZ • if the counter is 0 then exit the subroutine

' ...else move the partial result to A

MOV A,C ] C is used to store the partial dividend result

RAL rotate the most significant bit of A to the carry

SUB D ; subtract the divisor from A

JNC NOAD • if the carry flag is not up then jump to NOAD

ADD D ' ...else add the divisor back to A

NQAD:

MOV C,A ; move the partial dividend from A to C

CMC • set/clear carry flag by complementing

JMP NXT ; repeat this sequence of operations

HIGH ORDER LANGUAGE

E = E/D

Figure 2-5. Assembly Language [TI'IU78] and High Order Language

representations of a division of two numbers.

31
Chapter 2 - Overview of Microcomputers

and generate more efficient (i.e. shorter) assembly language programs or machine code.

Interpreters do not generate machine code, but perform the translation of

the HOL statements at the time of execution. As is the case with

compilers, interpreters can work in several stages: the HOL programs are

translated into an intermediate form, and the interpreter translates this

intermediate form into machine code at the time of execution. This twostep process speeds execution (which may be unacceptably slow if HOL

statements are interpreted directly) and may also reduce memory

requirements.

The advantages of HOL programs are that they take less time (i.e. are

less costly) to develop, easier to correct and change, and can be taken

from one microprocessor to another without the need for extensive

revisions (such is not the case with assembly language programs). It is

for these reasons that HOLs are used for most applications and some

systems programming. Table 2-8 shows some of the HOLs used in

microconputers

.

The disadvantages of HOLs are that they result in code which requires

more memory and takes longer to execute than programs written in assembly

language- The relative disadvantages of HOLs are dependent on the

quality of the compiler or interpreter, the nature of the HOL, and the

micrprocessor instruction set (i.e. the repertoire of operations which

the microprocessor is capable of executing). Early microprocessors (such as the 8080) were not intended for high level language programming, and

conpilation of conmon high order languages into their instruction sets is

not efficient- The instruction sets of newer microprocessors are

advertised as being designed specifically for the use of HOLs [MARK81].

Very High Level Languages

Very High Level Languages (VHLLs) resemble natural language most closely

and are the least computer-oriented. Many VHLLs do not even resemble the

sequences of instructions seen in the two previous classes of languages.

All require extensive preprocessing prior to execution, and most are

oriented toward a specific end (e.g. generation of a report, storage and

retrieval of information, solution of a set of equations, etc.). VHLLs

provide the most rapid means of developing application software. It is

possible to characterize two types of microccmputer-based VHLLs: generic

application programs and program generators.

Generic application programs include spread sheet processors, data file

managers, and other applications (see Chapter 4) which can be used to

perform many of the tasks that were traditionally programmed in HOLs.

These packages do not require extensive programming skills and can be

used by personnel with little or no formal canputer training (although seme initial support may be necessary).

Program generators are computer programs that generate other computer

programs in a formal HOL. They are a means of speeding software

development for programmers, but whether they can be used effectively by

32
Chapter 2 - Overview of Microcomputers

TABLE 2-8. COMMDN HIGH ORDER LANGUi^ES USED IN MICROODMPUTEE^

LANGUAGE APPLICATICN OOMMINTS

AREAS

BASIC All BASIC (B.eginner's ^ll-purpose Symbolic

Instruction £ode) was originally developed as a language to teach computer programming to university students in the 1950s. Because of its

initial simplicity, it was the first HOL

implemented on microcomputers, and has been

offered as a standard accessory on nearly every

microcomputer system. It has been extended far

beyond its first capabilities, and has become

the most popular language for microcomputer

programming. Unfortunately, the numerous

extensions have also resulted in there being

many incompatible dialects.

Pascal All Pascal was developed in the early 1970s also in

an academic environment. The primary goals of

its developers were to encourage the use of

structured programming and the generation of

readable and maintainable programs. Pascal

became popular because of its early

inplementation on microcomputers for courses in

computer programming in the mid 1970s. Although

it will probably not surpass BASIC as the most

widely used microcomputer language, its

programming constructs, data types, and software

engineering pedigree make it a language of

choice for many software developers.

OCBOL Managerial COBOL (£Qmmon Business Oriented Language was

and Adrtiini- initially developed in the early 1960s for

strative administrative purposes, and has become the

single most popular programming language for

mainframe computers. Its specialized features

for data entry and data managonent (with the use

of additional utilities) have made it attractive

for the same purposes on microcomputers.

Although not efficient in its use of memory and

slew in execution, its mainframe heritage, data

handling capabilities, and accompanying

utilities have made it a popular language for

business oriented applications on

microcomputers.

33
caiapter 2 - Overview of Microcomputers

TftBLE 2-8. COmm HIGH (MER LANGU^^ES USED IN MICROCOMPUTERS

LANGUA3E APPLICATICN COMMENTS

AREAS

C Systems C was originally developed in the Bell

Laboratories by the writers of the UNIX

operating system. As a consequence of the wide

use of UNIX in the academic community, C became

quite popular with conputer science students who

took their preference for the language (as well

as UNIX) to their jobs in industry. C became

popular as a systems development language for

microcomputers soon after the introduction of

16-bit microprocessors, when the first

microcomputer software conversions became

necessary and the adequate computing power

became available.

FOROKM Scientific/

Engineering

FORTRAN (EDEmula TRANslation) was developed in

the mid-1950s, and was the first high order

computer language. It is the most popular

language for scientific and engineering

applications on larger systens, and most FORERAN

compilers generate faster and shorter machine

language programs than those of other languages.

Like COBOL in the administrative area, its

mainframe heritage and large software installed

base makes FORTIRAN a language of choice for many

technical applications.

FORTH Real time

applications.

Systems

Programming

Forth is the first major HOL to be

developed on and for microprocessors. Its

applications unique approach to program creation

involves the building of code in terms of

procedures which are in turn defined by lower

level procedures. Several levels may be built

up over the lowest layer. This approach results

in the generation of very compact code which can be used in devices where memory is constrained

(e.g. micro-controllers).

3^
Chapter 2 - Overview of Microcomputers

non-programmers is not clear [STEW82, KILD83]. Most microcomputer-based

program generators are oriented toward administrative and managerial

users and include features for creation of records and files, data entry,

and report generation. They are therefore similar to data file

management systems (section 4.3) but may provide more flexibility for

sane applications because of their use of H(Xs.

35
Chapter 2 - Overview of Microcomputers

2.5. TEE USER INTERFACE

The user interface is that portion of the harc3ware and software that is

visible to the user. Although not sufficient in and of itself, a good user

interface is a necessary condition for successful microcomputer

implementation. Unfortunately, no definitive standards have onerged on what

constitutes a quality user interface, and some authors [SIMP82, CHAF83]

maintain that a good design is an art which can not be stated in a set of

rules. Nevertheless, progress in this area is evident in both the technical

literature and, more significantly, available hardware and software products.

2.5.1. Hardware Aspect of the User Interface

The hardware aspect of the user interface is the physical interaction of the

user with the equipment. The study of this interaction is called "ergonomics"

or "human engineering". The following characteristics of the CRT, keyboard,

and general system are usually cited as being important [PRES83, KETCH82,

CQHE82]

.

CRT

Display quality is important for minimizing discomfort for heavy users. Factors affecting this quality include the high resolution and wellfocused characters, non-glare screens, separate brightness and contrast

controls, and adjustments for the screen height and angle. Issues such

as color (white, green, or amber on black) and background (light on dark

or dark on light) are a matter of individual taste. Thus, the

availability of options is desirable. Oversize screens (i.e. larger than

80 columns by 24 lines) with high resolution bit mapping have been used

by several manufacturers as a means of enhancing the user interface in

more expensive units.

Keyboard

A detachable keyboard allcws greater flexibility in system placement and

the ability to enter data while facing the work rather than the CRT.

Keys that provide tactile feedback similar to a quality electric

typewriter are desirable for constant users, A keyboard with an

adjustable angle relative to the surface on which it rests and sculptured

keys can reduce fatigue.

General system

The most important characteristic of the user interface is reliability.

Other factors include a visually pleasing and unobtrusive design, low

space requirenents, low noise, and low heat generation.

2.5.2. Software Aspect of the User Interface

Chafin [CHAF83] has noted that ergonomics is particularly important for heavy

users but there is some question as to whether these issues are significant

for users who interact with the system for shorter periods. However, the

36
Chapter 2 - Overview of Microcomputers

software user interface affects all users: an application program which is

difficult and/or frustrating to use will not be utilized regardless of the

quality of the hardware on which it runs. As was the case in hardware, there

are few firm guidelines on characteristics of a quality software user

interface. The following list of features is gathered from a number of recent

articles in this area [CHAF83, B082, SMIT82, RUTK82].

Feedback to the User

Feedback is important for informing the user of the progress of

execution, the presence of problems, and the data which is being operated

on. Features in this area should include:

A prompt or message indicating when the program expects an input

from the user

The display of data input by the user

Some means of indicating the progress of a lengthy operation (e.g.

transmission of a file, disk formatting, or a sort)

Consistency

A command or keystroke should have the same meaning in every phase of the

program execution (or, if possible, in all programs). For example, if

the letter "A" is used for an "Append" command during data entry, it

should not mean "Abort" in the execution phase of the same program.

Minimization of Demands on the User ' s Memory

Both common experience and experimental evidence indicate that

recognition is easier than recall [B082, CHAF83, SMIT82]. Thus, tne

software should provide sane coaching for users as they proceed through

the various comonnand sequences of a program. Menus which list available

options and help screens which display instructions during program

execution are the most common means of providing this assistance.

However, these measures may prove cumbersome for users already familiar

with the program. The best solution is the provision of a "verbose" mode

which enables a novice or casual user to utilize the menus and help

screens and a "terse" mode which provides relatively little prompting but

allows an experienced user to enter cojnmands rapidly.

Additional features can minimize demands on the user's memory for data

entry and manipulation. The ability to use parts of the same CRT display

for noncontiguous areas of data (e.g. the display of two different pages

of text or nonadjacent columns on a spreadsheet) can be quite useful.

Simplicity

Simple arrangement of operations, commands, and displays minimize what

the operator must know in order to utilize the software. Simplicity does

not mean that a complete set of user prompts or necessary functions

should be deleted. However, it does require that the software developer

37
Chapter 2 - Overview of Microcomputers

understand the application (i.e. what is necessary, when it is necessary,

and what is unimportant) and is generally the result of good program

design.

Error Handling

Error handling provisions inhibit operator errors, enable the correction

of mistakes, and allow recovery from system faults. Among the

ccxnmands which can be provided are:

Ability to interrupt operations without aborting the application and

losing data

An "undo" command which allows the reversal of the last command

(e.g. restore data which was deleted by a previous cormand)

Editing of the current input line (e.g. the ability to erase part of a command line or to replace one or two digits in a long string of

numbers)

Autanatic creation of backup copies of data files

Other provisions for error handling include:

Messages which clearly indicate the error condition and suggest

remedial action

Detection and recovery from system faults (e.g. disk not ready,

printer out of paper, etc.)

Confirmation of potentially catastrophic ccramands prior to execution

(e.g. deletion or overwriting of an existing file)

Non-character Interactions

The use of (i.e- the ability of the software to support) pointing

devices (section 2.2), color, voice, graphics, and other non-character

means of data interchange can be useful for both program control and

data displays. At present, such facilities are offered on more

expensive microcomputers and a lack of standards prevents the

interchange of such information between different systems. However,

continued progress in this area is likely and will increase the

effectiveness of microcomputers in all areas of the organization.

2-6. TYPES OF MICROCOMPUTERS

The expanding market for microcomputers has resulted in a plethora of products

with a variety of differing attributes. This section discusses three

different viewpoints that may be useful for categorizing the differoit types

of systems which are available. Section 2.6.1 discusses categories of

microconputer functions; section 2.6.2 classifies microconputers on the basis

of size and weight, and section 2.6.3 describes the differences between single

and multiuser systans.

38
Chapter 2 - Overview of Microcomputers

2.6.1. Function

Four major categories of microcomputer functions can be established: general

purpose, word processing, education or entertainment, and laboratory

autOTiation or process control.

General Purpose Svstems

General purpose systems are appropriate for most Federal microcanputer

applications, and are the most common type available for business and

professional use. General purpose systems are produced in all size

classifications and in both single and multiple user configurations. The

most significant characteristic of these systans is their compatibility

with a wide variety of application software and peripherals which enables

than to perform tasks useful to all user classes. Other characteristics

include high quality keyboards and CRTs, large capacity disk drives, and

application program developnfient aids.

Word Processing Systems

Word processing systems are microcomputers which have hardware and

software features designed for word processing and associated functions

(e.g. mailing lists, form letters, etc). Some systens may be adaptable

to more general use by adding a standard operating system and/or special

hardware attachments. It is not clear whether these dedicated function

systems will continue as distinct products [HOUS82] because the smaller

demand leads to higher prices than general purpose systems. However,

others feel that the productivity benefits derived fron special hardware

and software features in these single purpose microcomputers outweigh the

cost disadvantages. These systems have been designed primarily for

clerical users, kxjt some administrative users with typing abilities may

be able to benefit from the electronic mail and document production

capabilities present in more sophisticated systens.

Educational/Entertainment Coirpjters

Microcomputers oriented toward educational and entertainment use possess

a number of interesting features such as color graphics (lew resolution),

music, and games software. Their low price and appealing software make

them appropriate for some Government training, education, and

entertainment activities. However, few applications and languages

necessary for performing normal business functions are provided. Thus,

despite their very attractive hardware price/performance ratio, they are

not suitable for most Government use. Other designations for this type

of syston include "home computers" or "domestic computers".

Laboratory Automation and Process Control

Microcomputers can be used for laboratory autcmation, automated testing,

unattended data collection, and related functions. Uiese microconputers

may use special operating systems and interfaces, but typically are built

around an industry standard bus. These systems are most appropriate for

39
Chapter 2 - Overview of Mcroconputers

specialized applications required by professional and technical users. Although these microcanputers can be adapted to more general purpose uses

in many cases, they may be more expensive and therefore less costeffective,

2.6-2. Size and Weight

Three major categories of microcomputer size and weight are currently

available: portable, transportable, and desktop.

Portable Computers

Portable computers, also called briefcase, lap, or notebook computers, are designed to fit into a briefcase and can be worked on in the user's

lap while traveling or away from a table. Some very lightweight

systems have limited memories and displays. However, their software

offerings include a text editor, communications package (generally

ASCII/TTY), a programming language (generally), and other applications

which make them appropriate to Government use. More capable systems

(which are generally heavier because of their larger batteries) may

have adequate memory capacities (both volatile and nonvolatile) to

support a standard operating system and applications.

These systems are appropriate for personnel who need access to a conputer while away from a desk (e.g. traveling or field work). Their

limited hardware capabilities (especially in peripherals) and resultant

limitations on software make them less desirable than other types of

systems in non-mobile applications. However, advances in both volatile

and nonvolatile monories, displays, and lower power microprocessors may

lead to systems with the same capabilities as present stationary

microcomputers

.

Transportable Ccaipjters

Transportable computers are designed to be moved frequently. They

generally weigh between 5 and 15 kg (11 to 33 pounds), and are packaged

such that they can be "folded up" into a suitcase- like package. They

differ from the previous classification of computers because their

greater weight and size preclude their use away from a desk.

The hardware capabilities of these systems span the range from portable

computers to the desktop systems described below. Lighter systens with

battery power have limited capacities. Heavier systems or those

requiring external power have greater capabilities and may in fact be

used in the same manner as some non-movable systems.

Transportable systems are appropriate for those who perform conputing at

a number of different locations, but who do not require the systons while

en route or in places where power is not available. However, despite

the fact that the computing functions may be equivalent, transportability

precludes the use of full sized CRT displays and other peripherals.

40
Chapter 2 - Overview of iVIicrocomputers

Desk Top Systems

Desk top systems are the most common size of microcomputers and are

appropriate for most Federal applications. They range from the size of a typewriter (useful where surface space is limited) to that of a desk

including self-contained work surfaces (suitable for some clerical uses).

2.6.3. Number of Users

Microcomputers can also be characterized as either single or multiple user

systans.

Single User Systems

Single user microcomputer systems embody the notion of "personal

computers" in that one person has control over the entire systen. They

are the most common type of microcomputer, and both their hardware and

software capabilities have increased dramatically since their

introduction in 1977.

Multiuser Systems

Multiuser microcanputers have large memories and powerful processors, and

are therefore sometimes referred to as "supermicrocomputers". They are

used in many situations where smaller minicomputers would have applied

previously. They do not provide their users with the total control of

single user systens, but are appropriate when a group works together.

Because of the specialized operating systems required for some multiuser

computers, fewer software offerings are available than for the single

user systens, and the application software running under these systems is

also generally more expensive. A second disadvantage is the possible

lowering of performance when many users share a single CPU. However,

the emergence of UNIX and variants in microcomputers as well as the

availability of new high performance 16 and 32 bit microprocessors may

change this situation. A special class of multiuser systOTS is called

multiprocessor systems because they contain several CPUs. One advantage

of these systems is faster response time. A second is the ability to

assign each user a CPU and to use a cannon operating systoiu

41
CHAPTER 3 - Federal Users

CHAPTER 3 - FEDERAL USERS

This chapter classifies Federal microcomputer users, describes their

characteristics, and identifies some of the issues related to their use of

microcomputers. The user classification contains the following four

categories?

Clerical

Clerical users include typists, junior secretaries, and data

entry personnel. Most clerical uses of microconputers involve

data input (either numbers or text) formatting, or transcribing. Document preparation and administrative data

entry are the most common applications of microcomputers.

Administrative

Administrative users of microcomputers include managers and

other Federal workers whose primary responsibility is related

to administrative tasks. Administrative uses of

microcomputers include accounting, budgeting and planning.

Professional

Professional users include natural and social scientists,

educators, legal workers, and others working in professional

fields. Their uses of microcomputers include data analysis

(primarily statistics) , modeling, and document preparation.

Technical

Technical users include programmers, engineers, and

researchers who perform their own computer-based system design

and programming. The primary distinction between technical

and professional users is the extent to which they perform

their own programming.

Table 3-1 lists examples of job functions falling into these categories, and

table 3-2 describes their distinguishing characteristics. Some users fall

into several categories simultaneously. For example a legal secretary in the

U.S. Courts performs administrative functions in addition to straight clerical

duties. Sections 3.1 through 3.4 discuss these classifications in further

detail.

42
CEIAPTER 3 - Federal Users

TABLE 3-1. JCB FUNCTIONS OF THE USER CLASSIFICATIONS

USER CLASSIFICATIGN EXAMPLE JOB FUNCTIONS

CLERICAL Secretaries

Clerk typists

Cashiers

Data Entry Clerks

ADMINISIRATIVE Managers

Administrative assistants

Budget analysts

Contract administrators

Accounting and auditing staff

Project managers

PROFESSIONAL Economists

Lawyers

(not in the ccmputer Doctors

field) Law enforconent personnel

Tax auditors

Cartographers

Librarians

Historians

Educators

Scientists (some classes)

Writers and Editors

TECHNICAL Ccxnputer Scientists and programmers

Engineers

(in computing or related Advanced technicians and technologists

technical fields) Scientists with computer backgrounds

^3
CHAPTER 3 - Federal Users

TABLE 3-2. CHARACTERISTICS OF USER CLASSES

CHARACTERISTIC CLERICAL ADMINISTRATIVE PROFESSIONAL TECHNICAL

Scope of computer Broad Broad

related tasks

Specia- Broad

lized

Necessity of

conputer-based systems for job

Conputer Background

High Low

Limited Limited

Low

Variable

Variable

Substantial

Relative amount of

systan usage

High Low Low High

Tolerance for Low

malfunctions, problems

Lew Low Variable

Availability of

personnel for

extensive training

High Low Lew Low

Need for subsequent High

support

High Variable Low

Need for technical

information

Low Low Low High
CHAPTER 3 - Federal Users

3.1. CLERICAL USERS

Table 3-3 relates the important characteristics of clerical users (taken from

table 3-2) to desirable attributes of their microcomputer systems. System

reliability, a well designed user interface (see section 2.5), high

performance, and effective documentation written for users with limited

technical backgrounds are requirenents which clerical users have in ccxnmon with other users. In addition, the following specific issues exist for this user class:

Limited Scope of Computer Related Tasks

Unlike other users, many clerical workers perform tasks of limited

scope (e.g. data entry, document preparation). For these workers

specialized systems which provide large screens, function keys (i.e.

keys which execute a series of ccramands or common keystrokes with a single key), specialized pointing devices, and other features that

reduce fatigue and make systems easy to use are more suitable than

general purpose systems.

Extended Use

Concerns on both the physiological impacts of CRTs and psychological

effects of extended computer usage have been raised in the United

States, Canada, and Europe [BOND83]. However, no definitive

conclusion could be reached from research on the effects of CRTs on

vision, pregnancies, cancer incidence rates, and musculo-skeletal

well being. Ketchel [KETC82] lists sane widely accepted ergonomic

guidelines for CRTs, but also states that the research base on

which to establish standards is not adequate.

Other measures to benefit clerical users (and improve performance)

are related to lighting, noise, and furniture. Ambient lighting

should be dim with higher intensity lighting on the work which

operators are transcribing. Printers and other noisy devices (e.g.

disk drives) should be hooded or placed in other rooms. Chairs and

desks should be designed for both operator comfort and efficiency.

Provisions in the layout of individual work stations as well as the

entire work area should allow for the special requirenents of CRTs,

keyboards, printers, and other devices.

A recent National Institute of Occupational Safety and Health

(NIOSH) study of clerical CRT operators investigated psychological

and social effects [COHE82]. As a result of the introduction of

large ccmputers, office work began to resemble an assembly line with

production quotas and rigid work assignments. This change resulted

in increased stress levels for clerical workers. Microcomputers can potentially cause the same types of problems. However, because

microcomputers allow the operator more control over the syston, it

is possible to avoid the assembly-line nature of work. Tasks can be

structured in a less restrictive manner to minimize the negative

impact on clerical users.

45
CHAPTER 3 - Federal Users

TABLE 3-3. CLERICAL USER CHARACTERISTICS AND DESIRABLE SYSTEM ATTRIBUTES

USER CHARACTERISTICS DESIRABLE SYSTEM ATTRIBUTES

Specialize in limited range of

computer related tasks

Necessary to use microcanputer for

job

Systems with extra features for

performing a limited set of tasks may

be preferable to general purpose

microcomputer s.

High system availability is required.

It is desirable that the microcomputer

offer some gratification in the course

of use.

Limited computer background

LC3W tolerance for malfunctions

and problems

Large portion of day spent using

microcomputer based system

Need for formal and extended

training period (days to weeks)

Need for subsequent support is high

Training, documentation, and the user

interface (section 2.5) must be

appropriate for this level of computer

expertise.

Reliable equipnent with high level of

maintenance is necessary.

Keyboards, CRTs, work surfaces, chairs,

lighting, noise levels, and other

environmental factors should be controlled.

Extensive training should be provided

as part of computer installation and

for new users; software user interface

should allow for several levels of

expertise (see section 2.5).

Syston design, procur^ent, managenent,

and operation should anticipate the

need for extensive user support.

Support requirements may consume more

departmental resources than system

acquisition.

1^6
CHAPTER 3 - Federal Users

Training

Effective training is necessary to provide clerical users with both

the expertise and confidence necessary to master their systans. For

example, Ketchel [KETC82] points out that approximately six weeks

are required to gain proficiency in word processing, but most

vendors provide less than three days of instruction. During the

ranaining five weeks, the organization should provide additional

training (perhaps through seminars and close work v/ith more

experienced users) as well as a lighter workload.

3.2. ADMINISTE^TIVE USERS

Table 3-4 shows the important characteristics of administrative users (taken

from table 3-2) and the resultant requirements on microcomputer systems.

System reliability, a convenient user interface, high performance, and

effective documentation written for users with a limited technical backgrounds

are requirements which administrative users have in common with other

classes. Special issues for this class of users include the following:

Support

As a result of the unpredictable nature of some aspects of

administrative and managerial work and the need for rapid response,

administrative users require a high level of support for their

microconputer related tasks [FERR82, sr4EJ83, S'IU082]. Such support

can only be provided if the software, hardware, and communications

(see section 5.3) are coordinated through a central support

organization.

Validity and Control of Administrative and Financial Software and Data

Applications relating to accounting, personnel, and other

administrative tasks which are performed on microcomputers are

subject to a number of laws (e.g. The Paperwork Reduction Act, the

Privacy Act, or the Freedom of Information Act), rules (e.g. 0MB

Circular A71), and guidelines (e.g. [GAD78]). Users with cavalier

attitudes toward checking their results can cause incorrect data to

propagate through the organization.

Additional concerns are related to data validity, protection, and

access. The transfer of data files from a mainframe computer to a microcomputer means that in addition to ensuring data security (i.e.

validity, protection, and access control) at the central site, the

activities of users at dispersed locations must also be monitored.

^7
CHAPTER 3 - Federal Users

TABLE 3-4. ADMINISTRATIVE USER CHARACTERISTICS

AND DESIRABLE SYSTEM ATTRIBUTES

USER CHARACTERISTIC DESIRABLE SYSTEM ATTRIBUTES

Broad Scope of Ccxnputer-related

tasks

Microcomputer can be helpful but is

not required for performing job

Limited technical background

Hardware, system software should be

compatible with popular application

software. Flexibility is more

important than extended features in

one given area. Integration of

application software is desirable (see

section 4.7).

The system should be easy to learn and

provide a rapid response so that the

productivity benefit is immediately

apparent.

Software should be designed with an

appropriately oriented user interface

(see section 2.5). Documentation must

be easy to understand. On-line help

or tutorials desirable.

Jimaller portion of day spent

using compater

Low toleration for system malfunctions

Short time available for training

Extensive need for subsequent support

The physical impact of the system

should be minimized. Documentation

should be easy to read and designed

for quick reference (e.g. summary

sheets, indices, reference cards)

Hardware and software reliability,

availability of spares, and short time

to repair are crucial. Overall

availability is more important than

capacity, performance and technical

sophistication.

Software must be easy to learn —

preferably without requiring more than

a short period of reading prior to

getting started. Help screens, mo^us,

and user interface features (section

2.5) should be oriented to minimizing

what the user must know in order to

work with the program.

Readily available source is required

for answering questions, solving

problems on system operation, software

canmands, initiating repairs, and

other user needs. Rapid response time

necessary because of short turnaround

time for many administrative tasks.

48
chapter 3 - Federal Users

3.3. PROFESSIONAL USERS

Table 3-5 relates significant characteristics of professional users (taken

from table 3-2) to desirable microcomputer system characteristics. System

reliability, a convenient user interface, high performance, and documentation

for users with limited technical backgrounds are requirements which

professional users have in canmon with other classes. The following issues

affect professional microcanputer users:

Application Development

Although the microcomputer industry has addressed the needs of

clerical and administrative users with a large number of products

and services, this has not been the case for many professional

applications because of the much smaller market. Most professional

workers are not skilled programmers nor is it cost effective to use

their time for software development. Thus, professional users must

resort to adapting existing packages to their needs (e.g. using a data base management system for statistical calculations) , using

software available on larger systems, or performing the calculation

by hand. The extent to which new software developnent or conversion

of existing software resident on mainframes to microccxnputers should

occur is not clear given their current hardware and software

limitations. Unrealistic central computing charges can encourage

microcomputer software development or conversion of mainframe

software to microccxnputers where it is not warranted.

Support

The most effective support personnel in highly professional settings

are those who have a background in both the profession (e.g.

medicine- geology) and in conpiting. Such personnel are rare, and

their ability to support dispersed users (as opposed to more

geographically concentrated users working on a single mainframe or minicomputer) is limited.

49
CHAPTER 3 - Federal Users

TABLE 3-5. PROFESSIONAL USER CHARACTERISTICS AND DESIRABLE SYSTEM ATTRIBUTES

USER CHARACTERISTIC DESIRABLE SYSTEM ATTRIBUTE

Broad Scope of Conputer-related

tasks

Microconputer can be helpful but is

not required for performing j<±)

Shialler portion of day spent

using computer

Systen flexibility is more important

than extended features in one given

area. The hardware and system

software should be compatible with

standard applications (see chapter 4)

and profession-specific software

packages. System flexibility is more

important than extended features in

one given area.

Hardware, software must be easy to

learn and use. The performance of

the microconputer should denonstrate

an immediate productivity benefit.

Impact of system on work area should

be minimized: small size, no extra pcwer requirenents, low noise,

minimal extra cabling, etc.

Documentation should be easy to read

and designed for quick reference (e.g.

summary sheets, indices, reference

cards)

.

Varying expertise in conputing

Lew to high toleration for syston

malfunctions

Software should be designed with an

appropriately oriented user interface

(see section 2.5). Documentation must

be easy to understand. On-line help

or tutorials are desirable. More

technically sophisticated users may

need systons and software with more

features and higher performance.

Use of microcomputers as adjunct to

daily tasks requires high availability

which impacts maintenance and support

considerations. Seme users may not be

as affected by malfunctions and can tolerate longer down times and may

have more flexibility in their choices

of systans and capabilities.

50
CHAPTER 3 - Federal Users

TABLE 3-5 (continued) . PROFESSIONAL USER CHARACTERISTICS

AND DESIRABLE SYSTEM ATTRIBUTES

USER CHARACTERISTIC

Short time available for training

Need for subsequent support

DESIRABLE SYSTEM ATTRIBUTE

Software must be easy to learn —

preferably without requiring more than

a short period of reading prior to

getting started. Help screens, menus,

and user interface features (section

2.5) should be oriented to minimizing

what the user must know in order to

work with the program.

Most users need a local source for

answering questions and solving

problems on system operations. Some

may require profession-specific advice

in conjunction with their computerrelated inquiries.

51
CEIAPTER 3 - Federal Users

3.4. TECHNICAL USERS

The important characteristics of technical users (taken from table 3-2) and

the resultant desirable system qualities are shown in table 3-6. Technical

users have some requirements in common with other users (e.g. reliability,

documentation, and technical support). However, because of their knowledge of

systons and their ability to program, technical users may find that systems

designed for less sophisticated users are too limited in flexibility,

performance, or capabilities. Some of the issues for technical users

Syst^ requipCTents variance with other users

For specialized and advanced microcomputer applications (e.g.

laboratory automation, data collection, or process control),

technical users may require systems that are not the same as those

used by the rest of the organization. Thus, agency policies on

microcomputer procurement and usage should not inhibit the use of

"non-standard" systems when needed. Conversely, technical users

should recognize the importance of support, ergonomic, and related

needs of non-technical users they may be asked to assist.

Alternatives to microcoirputers

A large body of software, expertise, and peripherals has grown

around dedicated minicomputers in process control, laboratory

automation, and other specialized tasks. Although the

price/performance ratios of microcanputer hardware are superior to

those of some larger systems, both technical users and project

managers should note the relative immaturity of microcomputers and

the consequent paucity of support in any but the most "mainstream"

of applications.

Integration with larger systems

Technical users who need to integrate mainframe software with a microcanputer applications (e.g. a package which queries a database

on a central mainframe and presents the data to the user through a spread sheet program) face difficulties because there are no widely

accepted standards for passing graphical or spread sheet data (see

Chapter 4).

include

:

52
CEIAPTER 3 - Federal Users

TABLE 3-6. TECHNICAL USER CHARACTERISTICS AND DESIRABLE SYSTEM AITRIBUTES

USER CHARACTERISTIC DESIRABLE SYSTEM ATTRIBUTE

Broad Scope of Conputer

related tasks

Varying necessity

for microcanputer

job functions

Technical backgrounds

System ccmpatibility with advanced and sophisticated

application, utility, and systems software is

important.

Microcomputers in daily use must have high

availability — possibly at some performance penalty.

Systems used for research and development should have

more advanced features and higher performance.

Technically sophisticated documentation at a sufficient level to facilitate modification (for both

hardware and software) is highly desirable. Elaborate

user interfaces^ introductory-level documentation

are less important. Systems with provisions for

software development and hardware interfacing may be

desirable.

Some portion of

day spent using

systen

Variable toleration

for system malfunctions

Short time available

for training

Need for technically

sophisticated

support

For casual users, minimization of the systen impact

on the user's system working area of microcanputer is

desirable (small size, no extra power, low noise,

minimal extra cabling, etc.). To steady users,

performance, reliability, ease of use are more

significant. For both constant and casual users

software commands should be uniform, self-evident.

Systen performance, capabilities, price may be more

important than overall reliability to users who can tolerate extended down times or are capable of

performing their own hardware repairs.

Software must be easy to learn — preferably

requiring only a short period of reading.

Documentation should still contain reference features

and examples, but technical users do not require

extensive tutorial material.

Technical users are generally capable of

understanding manuals and the overall operation of

systems. However, if they need to modify the

software or to install it on a new system, they may

require support on a highly technical level — well

above that typically provided by most vendors or

retailers.

53
chapter 4 - Microcomputer i^lications

CHAPTER 4 - MICROCOMPUTER APPLICATIONS

As noted previously, microccmputers are general purpose devices which can be

used for a variety of tasks. Application software is the single most

important conponent for transforming a general purpose microcomputer into a system for performing such tasks. Table 4-1 shows the most common types of

microcomputer application software and indicates where they are discussed in

this chapter. Section 4.6 discusses application software for more specialized

purposes. Section 4.7 explains how these applications can be put together,

i.e. integrated to increase the capabilities of microcomputers beyond those

provided by the applications running individually.

TABLE 4-1. TYPES OF APPLICATION SOFTWARE

APPLICATION

SOFTWARE TYPE

SECTION

WHERE DESCRIBED

PURPOSE

WORD PROCESSING 4.1

DATA MANAGEMENT 4.2

SPREAD SHEET 4.3

PROCESSORS

GRAPHICS . 4.4

COMMUNICATION 4.5

SPECIALIZED 4.6

SOFTWARE

Creating, editing, and printing documents

Organizing, storing, and retrieving data

Performing calculations and formatting for

tabular reports (e.g. budget forecasts)

Presentation of data graphs and preparation of

diagrams and illustrations

Data transfer to and from other systems

Specialized computation tasks associated with

various job functions (e.g. accounting, statistics)

5^
Chapter 4 - Microcomputer /plications

4.1. WORD PR0CESSI1«3

Word processing software is used for creating, editing, and printing documents

such as memoranda, letters, formal reports, address lists, indices, and

contracts. It is particularly useful for repetitive documents (such as form

letters) or those assanbled from pre-written, standard sections.

The origins of word processing are the text editing programs used by

data processing personnel starting in the late 1950s. The actual term was

coined with the introduction of the first magnetic card typewriter in 1964.

Although slow and limited by present standards, the magnetic card typewriter

spurred the developnent of many similar products over the next five years, and

the notion of a "word processing" department began to replace that of the

"typing pool". In the early 1970s, word processing systems based on small

minicomputers with video screens were introduced. The first word processing

system suitable for business and professional use on a general purpose

microccxnputer was introduced in 1976.

According to a 1981 user survey [AE?B0813, word processing is the single most

commonly used application on microcomputers. All Government workers who

produce documents of any length are potential users of word processing

software. Table 4-2 summarizes the applications of word processing software

for the four types of Federal users defined in Qiapter 3.

Clerical workers spend more than half their working day with documents

[TE1GE83]. An extended set of editing commands helps to reduce the number of

keystrokes and thereby increases productivity. Full format controls are

necessary for the production of high quality documents and include features

such as flexible pagination, footnotes, proportional spacing, superscripts,

and special symbols (e.g. Greek alphabet or mathematical symbols).

Because of the decreasing level of secretarial support provided to many

professional and managerial workers in larger organizations [TEGE83] , these

workers will benefit from software that is easy to learn and use. Unless they

are producing long or elaborate documents, a "light duty" package which has

limited features but is easy to use is more appropriate than a full-functioned

package intended for clerical workers.

Technical users can also benefit from the "light duty" word processing

software for much the same reason as professional and administrative workers.

For those who spend an extended amount of time in software development, a package which can generate machine readable source code files as well as

formatted text files eliminates the need to learn two different sets of

editing commands. Low memory usage can be advantageous to workers using word

processors in a multitasking environment (e.g. editing software in one task

and canpiling or running it in another)

55
Chapter 4 - Microcomputer Applications

TABLE 4-2. USES OF WORD PR0CESSIN3

USER CLASS APPLICATIOJS

CLERICAL Substitute for standard typewriter

Production of form letters, address lists, and mailing labels

Document assembly (i.e. creating a document from pre-written

paragraphs or sections stored on disk together with some

portions of specially written material. Examples are

contracts, RFPs, policy documents, or regulations)

Production of lengthy documents, formal reports, or cameraready copy for publications

ADMINISTRA- Short letters and internal memoranda

TIVE

Preparation of progress reports: may include graphs and

tables produced with other application software

Other light typing to support managerial functions

Preparation of messages for "electronic mail"

Composing of rough draft material for longer reports and papers

(preparation of subsequent final document by clerical users is

easier if the initial draft is created by administrative

personnel on a compatible word processor)

.

PROFESSIONAL Short letters, internal memoranda, progress reports (similar to

administrative users)

Preparation of professional documents: either in rough form or final copy (depending on typing ability of user and

availability of secretarial support). May involve inclusion of

graphics and tables.

TECHNICAL Short letters, internal memoranda, progress reports,

professional papers and reports (similar to professional

users)

.

Preparation of software, software documentation using word

processor for traditional text editing functions

56
chapter 4 - Microcanputer i^lications

Auxiliary packages to aid in the creation formatting, and production of

documents include:

Spelling Checkers

Spelling checkers are the most common auxiliary programs. They

operate in two phases: (1) the program scans a document and flags

words not found in the system dictionary and (2) the user either

adds each flagged word to the dictionary or corrects it in the

document- Because these programs do not detect misuse of words,

proofreading is still required.

Formatting Programs

Formatting programs are a useful supplement for those users who

produce large, formal documents (Requests For Proposals, legal

briefs, contracts, reports, and papers) or those requiring a good

deal of control over the physical appearance of the final copy (e.g.

those producing camera-ready copy). These programs read document

files that have been prepared with a word processor and produce a printed output- They are controlled by conmands which are embedded

in the text file when it is created. In addition, some provide a specialized programming language in which a series of formatting

commands is invoked whenever a certain event occurs (e.g. at the

start of every even numbered page or at the end of each page).

Bibliography Maintenance

Bibliography maintenance programs manage the bibliographic entries

associated with a report. References are flagged in the text and

the appropriate citations may either be inserted as footnotes or collected into a formatted bibliography at the end of the document.

Grammar and Style Checkers

Grammar and style checkers perform a limited syntactical analysis

and scan for "suspicious" (i.e. sexist, stereotypes, or trite)

phrases and terms by means of a dictionary. These programs may also

search for passive constructions, lengthy or terse sentences, or excessive use of the same structures. Some programs produce

statistical summaries of average sentence length, the degree of

variation in length, or the number of passive sentences.

Mailing List Programs

Mailing list programs are used to maintain name and address files,

but some also have the capability to individualize documents through

insertion of a limited number of words and phrases at key points of

the document.

57
Chapter 4 - Microconputer i^lications

4.2. DATA MANAGEMENT SOFTWARE

Data management software (also referred to as "data management systems") is

used for entering and retrieving data in formats and orders specified by the user (e.g. alphabetically or chronologically). Information can be retrieved

by names, accounts, dates, and a variety of other identifying criteria called

"keys".

The basic terms associated with data management software are records, fields,

and files. Records can be thought of as the computer representation of a paper form (e.g. application blank, receipt, maintenance request, etc.). The

record is made up of fields which can be regarded as analogous to the blanks

on the form. A group of records are stored in a file.

Figures 4-1 and 4-2 illustrate the use of a data management syston. Figure

4-la shows a form for recording data on microcomputer procurements

announcements frem the Commerce Business Daily. The information was entered

into records through the data manager and stored in the form shown in figure

4-lb. Figure 4-2 shows a report generated by the data management software

from the completed file. The particular package had extensive formatting

control which allowed the generation of a 132 column report and a choice of

which fields were presented (the reader should note that not all fields on

figure 4-lb are shown on figure 4.2).

Table 4-3 defines three broad classifications of microcomputer data managenent

systems. At present, microcomputer based data management systems are not

comparable to data base management systems on larger computers because of

their limited capacities and their inability to allow more than one user

access to a single file. More sophisticated data management applications may

be possible through the use of "data base machines" [INTE82, EAGL82] which

could be connected to several microcomputers.

Table 4-4 shows some of the applications of data management software.

Clerical users can enter data and produce routine reports. However, fewer

clerical personnel can be expected to gain the same expertise with data

management software as with word processing software. If a long or complex

sequence of conmands is necessary, the data management software should have a means of storing and executing these sequences without operator intervention

(i.e. a data manipulation language).

Administrative applications of data management software include accounting,

personnel, inventories, and other tasks which require the retrieval or consolidation of information from paper forms. If relatively simple

manipulations are required a card file manager is suitable. More elaborate

tasks can be performed with data file managers or a full data base management

system.

58
COS»€RCE BUSINESS DAILY ANNOUNCEMENT OF MICROCOMPUTER PROCUREMENTS

DATE: RECORDER:

REFERENCE NO.

FEDERAL SUPPLY CODE HEADING

SYSTEM TYPE

AGENCY

PRIMARY APPLICATION (IF KNOWN)

SECONDARY APPLICATION (IF ANY)

TERTIARY APPLICATION (IF ANY)

SPECIFIED AS BEING PART OF LARGER SYSTEM?

TYPE OF COMMUNICATION CAPABILITY

TYPE OF GRAPHICS CAPABILITY

DBMS SPECIFIED?

BRIEF SYSTEM DESCRIPTION OR OTHER COMMENTS

(a) Form used Ific recording (jata

00028 Jvoj '.j^lSH 4 WILDIFE SERVICE

J^4.2 ||5.2 | 0.0 |

F |

3 |

2 |

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0 jl6 BIT MICRO W/ 64K RAn|

(b) Representation fii deia 3^ fields on. 5 fgCOrd

gure 4-1. Representation of Data In a File Management System

59
11.'15.'82

CONTENTS OF C8D DATA S^SE

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0 28<?-3l(7i MICRO «/ 43K. BASIC

0 HP-AiOO

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0 TEi TRONIC 3530 DEV SYSTEM

0 COHHCDORE 'business MACHINES

0

0 *iAN6 CIS 140 SrSTEM

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0 HP 9845B FOR MICROCPTft DEVLPMT

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0 5 EA HP 9826. v32t.-lA.9325-4A,

0 12 APPLES ON OMNINET

0 83 CRTS AT 7 SITES

0 ZOBEi SllHD!2 Z30 (4 MHZ)

0 100 MICROCGMPiiTERS

0 7 HkSTAS I«Cl 2780 CCrMUN,

0 2 HP vm'jA for DATA ACSUISITIO

0 EASLE EDP ON CCRvUS OMNINET

0 5 STANDALONE, 4 SHARED lQSIC

0 123K RAM. lTR QLiAL PRINTER

0 8 PLOTTERS, 4 PRINTERS INCL

0 4 WORK STAS, PERIPHS FOR OIS

0 COMPUTER TEChNISHES MODEL 30

1 MICRO K.' 51 2K

I ONV; C8002 S'STEM

0 APPLICATION NOT SPEC

0 DECMATE Systems

1 NETUORit. TOPClCS?, TREND ANAL.

0 FCLiR Phase iv.'^o 0 CAlCOMP <'25 PE m PLOTTER

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0 TEKTRONIi COLOR bRApHlCS,HDCPl

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0 2 ?ERCs SfcOS 0 LANIER EZl. LIST/MERSE. MATH

0 ONVi 3002 40 MB DISK

Figure 4-2. Report Created by Data Management System from the File

Shown in Figure 4-1.

60
chapter 4 - Microconputer Applications

TABLE 4-3 CLASSES OF MICROCOMPUTER-BASED DATA MANAGEMENT SOFTWARE

CLASS APPLICATION DESCRIPTION

Card file

managers

Data file

Manager

Data Base

Management

Systems

Small, informal

and temporary

data files maintained by inexperienced users

More formal applications such as periodic reports

on personnel and

inventory. Useful

where more capabilities than Card

file managers are

needed but where

full Data Base

Management System

is not required.

Full accounting

systems, statistical packages, and

other applications

involving the use of multiple files

and a complex

sequence of commands.

Cardfile managers are the least

sophisticated data management software and

are generally the easiest to use. They are functionally analogous to a small box of

index cards on which the user makes

entries. Records consist of fields of

limited length. These systems can not

perform any arithmetic operations.

Operators can enter and edit data and

retrieve information by means of key words.

Reordering of the records on the basis of

alphabetic or numeric values of a specified

field may also be possible. Reports

produced by card file managers are

generally not suitable for formal purposes.

Data file managers can handle longer records

than card file managers, can perform arithmetic operations on the data in the files,

and provide the user with greater control

over the presentation of data reports.

Some file managers also execute sequences

of commands (i.e. programs), a feature

which simplifies the generation of routine

reports.

The primary difference between data base

management systens (DBMS) and the previous

classification is the ability to manipulate

multiple files simultaneously (a data base

can be thought of as consisting of files in

the same way that a record consists of

fields) . DBMS software also can execute programs in the same manner as the

more sophisticated data file managers. The

language in which these programs are written (i.e. the data manipulation

language) may be either the internal

language of the DBMS or a more standard

high order language (e.g. BASIC or COBOL)

.

61
Chapter 4 - Microcomputer Applications

Professional users can benefit from data managonent software featuring data

analysis transcription, and presentation. Data from surveys, samples, or experiments can be stored, retrieved, manipulated, and displayed with relative

ease. The data managenent system can be used to retrieve selected data which

are subsequently processed by another program (e.g. a statistical analysis

package or an econonetric model). Conversely, it is frequently possible to

take the data written on a file by another program and convert them to a form

usable by the data management software for post-processing. Although most

professional users are not expert programmers, they may be capable of using

the more powerful data file and data base management software to create

applications which significantly increase their productivity and enhance their

research capabilities.

Technical users can reap the same benefits as administrative and professional

users. An important benefit of data management software is the ease with

which record-oriented applications can be created for other users. This

benefit is apparent for administrative applications which require data entry,

file manipulation, and report writing. Data base management packages contain

modules to perform these tasks, and the application programmer need only

define the file contents, the specific calculations to be performed, and

certain parameters for the report writer. As long as the basic data base does

not change, adding additional reports or data entry routines is a relatively

simple matter.

62
Chapter 4 - Microcomputer i^lications

CLASS

CLERICAL

TABLE 4-4. USES OF FILE AND DATA BASE MANAGEMENT SOFTWARE

APPLICATIONS

Data entry (if software has provision)

Generation of routine reports

ADMINISTRATIVE Accounting

Inventory

Project management

Planning and budgeting

Personnel applications (smaller scale)

PROFESSIONAL

TECHNICAL

Maintenance of data files (e.g. questionnaires, chemical

analyses on samples, etc.)

Bibliographies

Statistical analyses (either directly in the data manager

or in conjunction with other software)

Development of software for other applications

Project management and monitoring (similar to

administrative users)

Data files and statistical analyses (similar to

professional users)

63
Chapter 4 - Microcomputer i^lications

4.3. SPREAD SHEET PROCESSORS

Spread sheet processors enable a user to define a table, enter data into that

table, specify the calculations to be performed on the data, and present the

results in a useful format. Figure 4-3 is an example of such a table, which

is also referred to as a "model", for a part of an engineering project budget

projection. The expected hours for each task were entered, and the spread

sheet processor calculated the total hours by job classification (e.g.

Technician, Engineer III, etc.) and the cost projections (in another part of

the table not shown). Because changes in the number of hours or labor rates

in any classification would cause a recalculation of the entire model, the

spreadsheet is a useful tool for planning. Managanent personnel can easily

manipulate time allocations to make the project fit within a certain budget or estimate the effect of cost escalations by raising labor rates by a given

percentage at the end of each year. Spread Sheet Processors are so named

because this process is analogous to the preparation of a "spread sheet" by

accounting and management personnel. These programs were conceived of as

managerial planning, budgeting, and decision making aids. However, they are

also useful for other problems where repeated calculations are necessary.

When VisiCalc, the first spread sheet processor, was introduced in 1979, its

purpose was not generally understood [BRIC83]. However, within a period of

two years, VisiCalc and its competitors became the most common microcomputer

application package for managerial users [MORL82]. A number of authors

[FERR82, WOHL82, ROMA83, HIRS83] state that spread sheet processors were the

primary motivation for the introduction of microcomputers into large

organizations.

There are two general types of spread sheet processors: interactive and noninteractive. Interactive packages perform the specified calculations as the user enters data or defines mathonatical operations. Non-interactive packages

require the user to create a file which contains all data, commands, and

formatting information before the spread sheet results are presented. The

primary advantage of interactive packages is the ability to rapidly develop

spread sheet applications. In a recent evaluation of three spread sheet

processors. Bishop [BISH82] reports development times of 1 and 2 hours for two

interactive packages and 8 hours for the non-interactive package. On the

other hand, some non-interactive spreadsheet processors use a form of model

development which is easier to understand. In addition, because a series of

non-interactive models can be run in batch mode (i,e, without operator

intervention once execution is started), a user needing to prepare a set of

monthly reports based on a relatively small number of inputs can use an editor

to prepare the files and can delegate the execution and printout of the models

to a less skilled assistant.

Table 4-5 shows possible applications of spread sheet processors for the user classes defined in Chapter 3. Because this software has been oriented toward

administrative and professional workers, clerical uses are limited. As was the

case with data management software, clerical workers can enter data or generate routine reports if the procedures are well defined and training has

been provided. However, such training will probably occur on the job because

little clerically oriented training (either material or courses) is available

for spread sheet programs.

64
LABOfi DlSTRIBUTIOt* Bv TASK

flONTH flONTH BCNTH MONTH flONTH «ONTH f.ONTH hONTH MOf<TH HONTH HONTH TASfc

13 14 1

J

l6 n 16 1*5 20 21 22 23 /J TTiT At

EtsGU^EER III 30 30 ^,\) 30 0 c Ov Ah

EliiSiKEER II 20 20 20 2'.' 2>.'- <:'.• v' ~ V

w'V 6'.i 7C

OS.'

TASt 1 ENblNEER 111 40 40 360

TECH 5TAFF 60 SO 720 SUBTOTAL 120 120 1080

TAS^ *.!

ENE.I«EEf> 11 15 15 15 15 60

E^'biNEEft 1 40 40 40 40 l60 TECHNICIAN 80 SO 80 80 320 SUBTOTAL 135 135 135 135 540

TASK 4,2 ENblXEER 11 - - 15 15 15 15 ------ - 60 ENGINEER I - - 20 20 20 20 80 TECHNICIAN - - 80 80 eo go . 320 SUBTOTAL - - 115 115 115 115 460

TASK 5 EN6INEER III - - - - - - 40 40 40 40 40 50 - 250

TECH STAFF - - - - - - 80 80 80 80 60 100 - 500 ENblNEER I 15 15 15 15 15 25 - 100 Subtotal 135 135 135 135 135 ns - 850

flONTHLV TOTAL HOURS 170 170 330 300 300 300 185 215 190 170 195 235 60 7000

60 30 30 30

50 50 50 50

60 60 60 60

160 160 160 160

PERSON HOURS

EN6INEER III 70 70 60 30 30 30 70 100 75 75 100 IIC 60 1780 TECH STAFF 80 80 - - - - 80 80 80 80 80 100 - 1720 ENcINEER II 20 20 50 50 50 50 20 20 20 - - - - {,20 ENblNEER I - - 60 60 60 60 15 15 15 15 15 25 - 1000 TECHNICIAN - - 160 160 160 160 1600

SR. ENGINEER - 210 SCIENTIST 70

40 40 40 40 40 50

80 80 80 80 60 100

15 15 15 15 15 25

135 135 135 135 135 175

185 215 190 170 195 235 60

70 100 75 75 100 lie 60

80 80 80 80 80 100 20 20 20

15 15 15 15 15 25

FIGURE 4-3. SAMPLE SPREAD SHEET MODEL

65
Chapter 4 - Microcanputer i^lications

Administrative users can independently develop sinrple mcxJels for planning and

budgeting but may need expert assistance for more elaborate models which

evolve from their initial work [FERR82]. If the spread sheets are used for

accounting purposes or critical decision making, validation or verification of

the model is necessary. Checks for correctness within the model (e.g. do all

the line items add up to the total allocation?) are a useful means of

achieving this result.

Professional and technical workers can use spread sheet processors for simple

data operations (e.g. addition, multiplication, seme transcendental s). Spread

sheet processors are also useful for parametric studies (i.e. the effects of

changing input values on the results) on simple models. Technical users can

use spread sheet models for both their own purposes and to support the needs

of other users.

66
Chapter 4 - Microcomputer Applications

CLASS

TABLE 4-5. USES OF SPREAD SHEET PROGRAMS

APPLICATIONS

CLERICAL Data entry and preparation of standard reports

ADMINISTRATIVE Budgeting

Project and contract monitoring

Financial and manpower projections

PROFESSIONAL Project and cost monitoring (similar to

admini strative

)

Simple parametric analyses

Specific calculations amenable to presentation in

tabular form

TECHNICAL Project and cost monitoring, parametric analyses

(similar to professional, administrative)

Preparation of applications for other users

67
Chapter 4 - Microccmputer i^lications

4.4. GRAPHICS SOFTWARE

The increasing capabilities of microconputer systons and the growing amounts

of information which Government workers must handle provide incentives for

the use of graphics software. Microccmputer based packages encourage graphics

in situations where they have not previously been used because they can be

generated rapidly and inexpensively and they are easily modified. Even

where the microcomputer generated output is not of adequate quality, it

provides good drafts and speeds the production of final copy. Graphics

systems can be classified as follows:

Data Display

Display of numerical data generated by other applications or manually

entered by the operator is generally handled through the three types of

graphs shown in figure 4-4. Bar graphs (4-4a) can be used to display

absolute quantities (e.g. the amount of coffee imported frcm Brazil each

year), pie charts are useful for displaying proportions (e.g. the

proportions of coffee from South America, Central America, and Africa),

and scatter plots are a general means of displaying the relations between

two or more variables.

Drawings and Illustrations

In addition to graphs for display of numerical data, microcomputers can also be used to create drawings. Less sophisticated systems can be used

to create simple line drawings such as block diagrams, flow charts, or figures created with a digitizer. More sophisticated systems can create

conplex engineering drawings and manipulate the data to enable canputer

aided design. Because of their additional hardware requirements, the

cost of these latter systems can be several times that of the basic

microccmputer.

High Resolution Color Graphics

High resolution color graphics represent the most sophisticated level of

microcomputer based graphics. They are useful for cartography, medical

applications, and specialized technical tasks. This capability requires

additional hardware and software which is beyond the scope of most users

(at the time of this writing). However, the advent of lower cost

memories, color displays, color hard copy devices, and 32-bit

microprocessors may bring the cost of high resolution graphics down to

acceptable levels in the near future.

The suitability of a graphics software depends not only on its processing

ability but also on the output devices it supports. Available graphics

software can produce drawing on printers, plotters, or other devices.

Graphics on printers can be produced with either the ASCII character set or

with special printer positioning and dot controls. Table 4-6 describes

graphics output from common hard copy devices, and figures 4-5 through 4-8

show some examples (Chapter 2 contains a more complete description of the

devices themselves).

68
ai S2 S3 B4 8& 86 67 68 8) SO 91 YEAR

(a) Bar Chart

(b) Pie Chart

A - • 0 — a - c

(c) Scatter Plot

Figure 4-4. Types of Graphics for Display of Numerical Data

69
Chapter 4 - Microcanputer i^lications

TABLE 4-6. CHARACTERISTICS OF GRAPHICS HARD COPY OUTPUT

TYPE OF OUTPUT RELATIVE RELATIVE RELATIVE

SPEED COST QUALITY

Character Printer* High Low Low

Dot Matrix

printer with

control over individual

dots and precision print

head control

Fully formed

character printer with precision print

head control

Plotter

Ink jet

printers.

Laser

printers

COMMENTS

Major advantage is ability

to use ASCII character set

-provides greatest flexibility, can be transmitted to

other systems, and can be

embedded in textual documents (e.g. diagram in instruction manual)

Medium- Low Medium- Dot matrix printer with bit

Low Low mapped capabilities can produce adequate graphics for

informal documents- No

standards for non-ASCII matrix patterns, print head

control. Thus, no transportability

Low Medium Medium- Fully formed character

High printers with precision

positioning can produce the

same quality lines and

symbols as dot matrix

printers and can produce

higher quality characters.

The primary disadvantages

are the absence of standard

printer positioning controls

and the length of time

necessary to produce a plot.

Low High- High Actually draws the graphics.

Medium and is capable of the best

quality (depending on

driving software). Not

efficient where much text

is to be included.

High High High Costs expected to decrease,

reliability, throughput

expected to increase as volume increases- Suitable for

both text and graphics

* either a fully formed character printer or a dot matrix printer being used

without individual dot addressability (see section 2.2)

70
Chapter 4 - Micrcxxxcputer Application Software

SCMTES IM.OT OF 30 S T VI DA RT) I Z EO V*L'Jf S OF RI2U VS. PRZIi*

-1

1 1

1

17

1 1

1

1 3

?

1 3 1

1 1

1 1

1

1

I'FAM STn.nrv. ^0BI7. Vfn. 1 . 2 32 3€-ni 3.3';n5E*of S^"PLE SIZE = 30

Figure 4-5. Scatter plot produced by a character printer: lines and points

are created using syiiix>ls frcm the ASQI character set

71
Chapter 4 - Microconputer Application Software

li.i

Ml I 1 i

72
chapter 4 - Microcccnputer Application Software

AVERAGE STOCK PRICES MARCH 1981-FiBRUARy 1982

75

35H 1 1 1 1 1 1 1 1 1 1 1 MARAPRMAYJUNJULADGSEPCXn'NCVECCJANFEB

MDOTH

Figure 4-7. Plot Produced by fully formed character printer with precision

position control (1/120 " horizontal; 1/48 " vertical)

73
Chapter 4 - Micrococpjter i^lication Software

0.250

0.225

0 30 60 90 120 150 180 210 240

DISTANCE FROM EDGE

Figure 4-8. Scatter Plot produced by plotter

74
Chapter 4 - Microcomputer /plications

Ideally, one would like to consider the capabilities of graphics software and

hardware devices independently. Unfortunately, standards for graphics have

not yet reached the point where this is possible. As a result, graphics

capabilities can not be obtained simply by buying the appropriate software,

and many users will not find a suitable canbination of graphics hardware and

software for their system at any price. Major software vendors, the Merican

National Standards Institute (ANSI), and the Association for Computing

Machinery (ACM) are attempting to address this problem by offering products or developing standards. However, there are no clear "winners" at this point,

and graphics standards remain a controversial and unresolved area.

Table 4-7 shows the uses of graphics software. Clerical workers may use

graphics output as part of their document preparation tasks or they may assist

users of other classes in the preparation of illustrations or graphs. The

primary use of graphics for administrative users is to present data

efficiently and to prepare diagrams (e.g. organization charts, project

schedules, etc.) for reports and meetings. Professional users may employ

graphics for the presentation of experimental data as well as line and bar

charts. Technical users have applications similar to those of professional

users. In addition, as microcanputer-based CAD systens becone more powerful,

they may increase the productivity of technical personnel.

75
Chapter 4 - Microcomputer implications

TABLE 4-7. GRAPHICS SOFTWARE APPLICATIONS

USER CLASS

CLERICAL

ADMINISTRATIVE

APPLICATIONS

Preparation of charts and graphs based on input

supplied by others or generated in the course of the

preparation of normal reports.

Graphs for reports, briefings, and other

presentations on the financial and management aspects

of department, contracts, other areas of

responsibility. Graphs are often a more efficient

way of presenting information and retaining audience

interest.

Generation of diagrams for internal use (organization

charts, project management schedules and diagrams,

etc.)

.

PROFESSIONAL Presentation of data generated by user or by other

programs.

TECHNICAL Presentation of data (similar to professional users)

.

Ccmputer aided design.

Generation of diagrams for design documentation,

reports, presentations.

76
chapter 4 - Microcomputer /plications

4.5. MICROCOMPUTER COMMUNICATIONS

Because Governinent activities require the coordination of the work of many

individuals, it is appropriate that microcomputer systems should be linked

together. This section discusses communication software and some of the

accanpanying issues of types of data canmunications systems.

Microcanputer communication software can be used by all classes of Federal

workers as shown in table 4-8. Reliability, performance, and ease of use are

important considerations in all user cases. A major use of computer

communication for clerical workers is as a replacement for the physical

movement of documents. Efficient communication can also enable several people

to work on the same document simultaneously even if they are physically

separated. The value of this capability may grow in response to pressure for

increased clerical productivity.

Teger [TBGE83] points out that the majority of managerial activities relate

directly to communication. Thus, managerial and administrative users can

benefit from the ability to quickly and easily move messages, data, and

documents by means of microcomputers.

The document and data transfer capabilities useful to the previous two classes

are also applicable to professional users. These users can perform their

mainframe computing tasks using microcomputers and ccxiimunication software.

File transfer capabilities would enable users to perform much of the

reduction of the mainframe program printout into a form suitable for

interpretation or presentation).

Technical users can benefit fran all these capabilities. In addition, they

can participate in the dissemination of botn computing-related topics by

accessing both public and private research networks. These networks often

contain public domain or Government developed software which these users can modify and introduce into their own agencies.

As with all types of computers, data communication with microcomputers

involves many technical issues. The Open Systens Interconnection Model of the

International Standards Organization [ISOBI], currently the daninant framework

for the design of computer communications systons, has seven different levels,

each of which may have one or more different standards associated with it.

Successful data communication requires that the communicating systems be

compatible at all levels; attaining this compatibility is generally a canplicated and highly specialized task.

However, the field is continuing to develop, and a unified approach to data

communications is emerging. One major international effort, the ISO Open

System Interconnection Model, was mentioned in the previous paragraph.

Another international recommendation, X.25, defines a means of data

interchange between systems through a public telephone system. Federal

initiatives include the selection of a limited set of options of X.25 to

facilitate rapid and efficient data conmunication [NBS83d] and a standard for

exchanging information between computer based message systems [NBS83e].

77
Chapter 4 - MicrocOTiputer /plications

TABLE 4-8. APPLICATIONS OF COMMUNICATIONS SOFTWARE

USER CLASS APPLICATICN

CLERICAL Transmission of documents to other sites for hard

copy output or review by remote personnel, storage

and retrieval of documents from centralized file

servers (on local area networks or in conjunction

with larger computer installations)

.

AEMINISIRATIVE "Electronic mail" (i.e. transmission of monoranda,

messages, reports by means of microconputer

communications)

.

Transfer of financial and administrative data to

and from larger installations.

PROFESSIONAL Access to data bases on either an internal system or from an information utility or value added network.

Access to mainframe computer for dumb terminal/

intelligent terminal applications.

Electronic mail (similar to administrative users)

.

TE(2HNICAL Access to larger computers and computer networks for

applications similar to professional users.

Use as software component in development of

distributed computing networks.

78
Chapter 4 - Microcomputer i^lications

Data COTimunication standardization efforts within the Government are described

in a recent article [BLAN82]. Readers intending to implement systans are also

referred to the "Current List of Documents" from the Systems and Network

Architecture Division of ICST [NBS83f].

Section 4.5.1 discusses asynchronous serial communication and section 4.5.2

discusses data communication using telephone lines, a common transmission

medium for asynchronous communication. Section 4.5.3 discusses microconputers

as parts of a minicomputer or mainframe-based network, and section 4.5.4

describes local area networks.

4.5.1. Asynchronous Serial Conmunication

Asynchronous serial communication requires only an RS 232C port or a modem

(see section 2.2.8) and is therefore one of the most widely used conmunication

methods. Microcomputer software for asynchronous serial communication

software is available for at least the following three general functions:

Teletype emulation

Teletype or "dumb terminal" onulation allows the user to communicate with

a remote system as if the microcomputer were a teletype terminal — i.e.

to display characters as they are received and to send them as they are typed in. Examples include retrieving news items or responding to

electronic mail on a larger remote syston.

Teletype emulation requires a minimal amount of processing by the

microcomputer, and is the "lowest common denominator" of computer

communications. Thus, most mainframe computers and (and computer

networks) support this type of communications. However, because all

processing and storage must be performed by the host conputer (as opposed

to the local microconputer) , communication, remote computing, and storage

charges can be relatively high.

File transfer

File transfer is the ability of the microcomputer to either send or receive (and store) a file, and is a useful capability for manipulating

data either before it is sent or after it is received. Some general

purpose file transfer programs require that the files contain only ASCII

characters. Where material containing object code or arbitrary symbols

is to be transferred, more advanced file transfer programs must be

employed.

File transfer is a useful capability for pre or post processing of data.

For example, one could use a text editor or word processor to prepare a source program or document file, send the file to the central computer,

and then perform additional operations (e.g. compilation and execution or simple printing) at the remote site. Another example is the accessing of

financial data contained in files on the mainframe, storing them in a file on the microconputer, and subsequently manipulating that data with

local applications software (e.g. a data file manager for production of a

report)

.

79
Chapter 4 - Microcomputer i^lications

Intelligent Terminal Emulation

Intelligent terminal emulation packages allow a microcomputer to replace

proprietary or specialized terminals that have functions beyond those

provided by a teletype terminal. This type of emulation processes

specialized canmands from the ronote computer to enable the display of

variable intensities, color, or local editing. The integration of a microcomputer into an existing mainframe network may require more than

the simple purchase of a software package, and coordination with the

central data processing organization is necessary.

4.5.2. Microconputer Canmunications Via Telephone Lines

The easiest way to establish a communication link is by means of a telephone

and a modem. A modem is a device which converts digital signals to an audio

tone sent over telephone lines. Modems may be internal to the computer or externally connected by means of either an RS 232 port (section 2.2.8) or an

accoustic coupler. There are three major disadvantages to the use of

telephone lines:

(1) Telephone lines are not designed for data communication. Thus, data

transmission is slow and not always reliable. The most ccxrimon data

transmission rate is 300 bits per second (approximately 30

characters per second). IVhile such transfer rates are adequate for

short messages, a document of 10 pages may require 20 minutes or

longer for transmission.

(2) Extensive use of telephonic data communications ties up lines,

switches, and equipment needed for voice communication, and can

result in excessive telephone charges. If several microcomputers are

connected to a single larger installation through telephone lines,

specialized devices such as multiplexers or concentrators can be

used to reduce the number of lines. However, their use is neither

cheap nor always possible.

(3) Establishing a connection between two computers can be an awkward

process. The most usual way is to dial a telephone number, wait

for a tone from the receiving modem, and initiate data

communication. Microcomputer software and hardware capable of

automatically establishing contact by means of autonatic dialing and

log-on are available, but sophisticated telephone communication

equipment can easily cost as much as the microconputer.

These problems make tele^ione communications less than satisfactory for links

where a constant connection is required or a high volume of data is

transmitted. Special types of interoffice telephone systems called Private

Automated Branch Exchanges, or PABXs are available for overcoming some of

these problems in a local setting. However, PABXs are costly, and full

utilization of their capabilities requires custom design and technical

expertise. Thus, implementation of a PABX may result in a system which costs

several times the original purchase price of the microcomputers.

80
Chapter 4 - Microcomputer />^lications

Despite these drawbacks, the low technical risk, adequate performance, and

ease of establishing a connection have resulted in telephone lines becoming a popular means of microcomputer communication. The long term prospects for

telephone data communications can be judged by the fact that integral modems

come either as standard items or readily available accessories for the most

widely selling systems.

4.5.3. Microcomputers in Larger Computer Networks

Microcomputers can be incorporated into networks based on a larger computer

in a variety of ways. Connections can be established using either telephone

lines or connections through the output port of the microcomputer to the

larger system (see section 2.2.8). Higher data transfer rates can be

established using specialized conmunication hardware interfaces, specialized

software, intermediate communication controllers, and other vendor-specific

techniques.

Microcomputer software which emulates teletype or intelligent terminals

(section 4,5.1) can be used to establish a minimal level of interaction

between the two systems. However, higher levels of integration are beginning

to appear. One example is the combination of microcomputers and mainframes for

database inquiries [JOHN83b]. The microcomputer provides a "friendly"

interface which requests data from the user and formulates a command which can be processed by a mainframe data base management syston. Security provisions

are addressed either by having the microcomputer provide data on the identity

and authorization level of the user making the request to the central syston

or by having a local determination of access authorization. An even more

sophisticated interaction is possible if a microcOTiputer application package

such as a spread sheet analyzer is integrated into the "friendly" interface.

This integration allows the user to retrieve and process data without regard

to where it resides — i.e. true distributed processing.

Some manufacturers of both mainframe and microcomputers have introduced

special adaptations of their microcomputer products that are designed

specifically to function in their mainframe computer network. By means of

both software and hardware modifications, these units have capabilities which

are greater than standard microccsnputers with intelligent terminal emulation

software. Examples of such capabilities include being able to simultaneously

execute microcomputer software while accessing the remote mainframe and the

ability to manage several mainframe sessions from a single microcomputer.

The close coordination of microcomputers and mainframes raises a number of

management problens. Uninhibited access to the central mainframe can result

in an excessive load. Concerns of data validity, integrity, and security are much greater when users have both easy access to central agency data and the

ability to manipulate it using microcomputer applications which have not been

validated and approved by the central data processing entity. Finally, if

microcomputer procurements have been made without regard to the possibility of

integration, it may be technically difficult or impossible to achieve the

levels of performance and reliability necessary to implement distributed

processing.

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Chapter 4 - Microcomputer Applications

4.5.4. Microconputers in Local Area Networks

Local area networks consist of devices interconnected by high-speed short

distance lines. Among the potential benefits of local area networks are the

sharing of expensive peripherals, the facilitation of communication among

microconputers, and the integration of microconputers with minicomputers and

other types of office automation products. Local area networks vary in

performance and cost. The least expensive networks can be implemented at

approximately $500 per node (i.e. microcomputer or peripheral) while more

powerful systems can cost ten times as much [EISE83]. At least 40 firms were

active in local area networks at the end of 1982 tSMEJ82, HU3H82]. However,

the number of firms with viable products, support, and distribution is

probably much smaller. One recent article [FOST83b] cites an expert who feels

there are only two practical microconputer-based local area netwprks.

Lwer priced systems are available with transmission rates of .1-2 megabits

per second, and supporting software may allow the sharing of a hard disk.

High performance systems use rates of approximately 10 megabits per second,

and software support includes electronic mail and support for sophisticated

printers, long-haul communication devices (generally using asynchronous serial

communication over telepiione lines), and mass storage devices.

Local area networks (LANs) can be characterized in a number of different ways.

TWO commonly used characteristics are topology and coirmunications medium.

The topology refers to the manner in which they are connected. Figure 4-9

shows three common topologies available in current local area network

products. The star facilitates the sharing of resources such as hard disks,

communications devices, printers, or common data files which are located at

the central node. Two popular microcomputer-based local area networks use this topology [EISE83, SAAL83] which is appropriate as a small and low cost

means of implementing a network. However, because traffic is limited by the

throughput of the central node which is in turn limited by cost constraints,

such a topology is not optimal for a large number of nodes.

The linear bus topology is also useful for sharing devices as well as

facilitating communication between any of the nodes. The linear bus has been

standardized on 4 levels of the ISO reference model [IS081] as IEEE Standards

802.3 and 802.4 [IEEE83a, IEEE83b]. Because of its developmental and

commercial history, the linear bus has become increasingly important for

medium and large sized local area networks.

At present, the ring topology is not as prevalent as the star and linear bus

but has been used in process control applications together with the token

passing access method. In this application, each monber of the network gets

access to the communication channel (i.e. the token) for a set time at

predefined intervals). Standardization for ring-based local area networks

using token passing is curroitly in progress as IEEE P802.5.

82
STAR

LINEAR BUS

RING

Figure 4-9.

O

Tc|X)logies for Local Area Networks

83
chapter 4 - Microccanputer Applications

The coimnunications medium describes the nature of the links between nodes.

Lower performance systems use "twisted pair" links, i.e. copper wire and

connections similar to the RS-232 (section 2.2.8) standards. The advantages

of this medium are low cost and the ease of connecting and disconnecting

devices. Higher performance systems use coaxial cable and radio-frequency

type coimiunications. TVo types of transmission techniques are available over

coaxial cable: "baseband", in which all devices share a single communication

channel and "broadband", in which devices can ccmmunicate with each other on

dedicated frequencies (some broadband networks have a baseband channel).

Optical fibers, the newest communication link, allow the highest data transfer

rates and solve many of the problons associated with electrical signals (power

surges, radio frequency interference from electric motors, etc.). However, it

is the most difficult and expensive communications medium to install, and is

still somewhat experimental.

In addition to the general type of network to which the microcanpater will be

attached, there are additional issues associated with the software support.

For example, one of the most common motivations for using a LAN is resource

sharing. One such resource is a mass storage device (a "file server"). In

some current systems, the file server is nothing more than a hard disk drive

with a controller to prevent several users frcm accessing it simultaneously.

Each user has an independent directory, and no provisions are made for file

sharing. More sophisticated file server software allows for the accessing of a single file by multiple users with access controlled by means of a password

system. A still higher level of sophistication would allow simultaneous

access to a given file (e.g. for data entries and queries from multiple

operators). If the network architecture allows for the inclusion of a minicomputer as a file server, other functions at these higher levels might

provide for some form of distributed processing for software development (e.g.

ccxnpilation on the central device while editing is performed locally).

Local area networks are a topic in and of themselves, and a complete

discussion of the issues involved is beyond the scope of this report. An MBS

publication [NBS82] contains a more complete exposition of this subject.

Protocol and physical interfaces of local area networks are currently in the

process of being standardized under the IEEE Project 802. In addition to the

802.3, 802.4, and 802.5 standards which were noted above, work is under way on

a metropolitan area network (802.6) as well as an overall architecture (802.1)

and logical link control protocol (802.2).

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Chapter 4 - Microcomputer Applications

4.6. SPECIALIZED SOFTWARE

Specialized software includes application packages not covered in the previous

sections. Traditionally, these specialized programs have been written by the

end user (or programmers employed by the end user) because of the small number

of installations with the same hardware and software, a fact which inhibited

the development of third party software. However, the advent of

microcomputers changed this situation, and many specialized software packages

are currently available for purchase. In addition, other microcomputer

software such as data base management systems or spread sheet analyzers can be

used to construct applications. Custon software development is also an option

for unique applications.

Purchased Software

Although applications such as project management, capital assets

management, or electronic design are of less general interest than word

processing, packages have been developed for these purposes.

Unfortunately, they are not as readily available as the more standard

types of applications and are often more expensive. Despite these

difficulties, specialized software packages can significantly increase

the productivity of specialists working in these areas, and the cost is

frequently recovered within a short time after their purchase.

Data Base Management Systems and Spread Sheet Analyzers

Users who cannot find software for their application should first

consider a data base manag^ent system or spread sheet analyzer before

enbarking on a software development effort in a more traditional computer

language. Their generality has enabled these software products to be

extended beyond their original intended applications. These programs

have been used for accounting, statistics, cost estimation, project

management, and real estate calculations. Even if the generic

applications do not provide adequate capacity over the long run, they can serve as a guide and specification to the developers implementing the

final product.

Custom Programming

In cases where software meeting the needs of end users is not available,

custom programming may be the only alternative. This is the most costly

and uncertain option and should not be undertaken without expert

assistance in both iranagement and development. These efforts are also

appropriate if the product will be used on many systems. In other cases,

the software development aids, utilities, and the experience base on

larger systems may favor the development of the application on a minicomputer or a mainframe.

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Chapter 4 - Microcomputer i^lications

4.7. APPLICATION INTEGRATION

The previous sections described how applications can be useful to Federal

workers as stand-alone programs. However, if these programs can be

integrated, i.e. made to work together, microcomputers can provide greater

benefits. For example, a formal report containing textual material, numerical

data, and graphics prepared on a microcomputer requires a word processor,

spread sheet analyzer, and graphics program. Changes in the data would

require that the user re-execute all three programs and reassemble the

document. However, if the applications were integrated, users would make only

a single set of corrections to the spread sheet model, re-execute the

integrated program, and produce the final document. Table 4-9 lists some of

the benefits of integration.

Integration can be achieved through common file structures, integrated

programs, multitasking operating systems, and application environments.

Zil£ Conpatibility

File compatibility means that one application can read and manipulate the

file of another. In the example cited above, the word processor and

graphics program can read files produced by the spread sheet analyzer.

If the change in the example given above were made in a system with

compatible files, the user would only make changes in the spread sheet

program, and incorporate the results into the other applications.

Because of the ASCII standard, compatibility of files containing only

characters is not a problem. Thus, the file-level integration of

character oriented applications such as word processing or data

management is generally possible. However, file compatibility is more

difficult for spread sheet and graphics software. There is no current

standard for representing grapdis and spread sheets (i.e. the calculation

rules and the floating point numbers) which is generally accepted,

although a number have been proposed (e.g. [SOFT80]). The most practical

solution for this level of integration is the use of "companion"

packages, i.e. a set of application software which can process the files

of other software in the same product line. The disadvantage of this

approach is that users do not have the flexibility to choose the best

application in each area. Once they have chosen the first package, they

are comnnitted to the rest of the product line.

Integrated Packages

Integrated packages contain several applications in a single software

product. Integrated packages are easier to use than separate file

compatible software when several applications are being used for a given

task. Changes such as those presented in the above example could be

accomplished without having to execute applications individually and then

return to the operating ^stem.

One major disadvantage of integrated packages is similar to that of the

companion software packages: the user is committed to a single set of

applications — one or more of which may be inadequate. A second

86
Chapter 4 - Microcomputer Applications

disadvantage is that the files produced by integrated packages may not be

file compatible with any other software even if the data files contain

only alphanumeric characters (i.e. word processors and data managers).

Thus, unless the integrated packages produce ASCII files (or the user is

sufficiently knowledgeable to create them by means of operating syston

utilities), the output of the integrated packages can not be transmitted

to other systans or used by other software.

Single-user Multitasking Operating Systems

Single user multitasking operating systems combine the advantages of file

compatible software with the ease of use of integrated packages. Because

multitasking systems allow the "simultaneous" execution of a number of

tasks, users can keep several applications in RAM and move between them

by means of a simple keystroke rather than a series of commands to exit

from one application before starting up another. A major advantage of

this approach is a greater choice of individual applications which

alleviates the problems of being constrained to a single product line.

Disadvantages include the substantial hardware requirements of

multitasking operating systems and the difficulty of learning how to

"juggle" several applications simultaneously, a problem which may

preclude this approach for less sophisticated users.

Application Environments

i^lication environments are elaborate user interface programs which work

in conjunction with the operating system to provide users with the

ability to control several applications simultaneously. These

interfaces make the transitions between tasks easier than multitasking

operating systOTS for unsophisticated users. A significant advantage of application environments is that their

developers have defined file structures which overcome some of the

problems noted earlier. "Thus, graphics can be placed in the middle of a text file and transmitted to other systems (if they are equipped with the

same environments). Seme of the major software vendors who sell these

packages have stated their intention to encourage independent

programmers to develop applications in the same manner as operating

systems. Thus, these environments may eventually provide users with a wide range of choices of mutually compatible applications. However,

current software offerings for most application environments consist of a single line of products with the same disadvantages noted above.

8?
Chapter 4 - Microcomputer i^lications

APPLICATION

TABLE 4-9. APPLICATION INTEGRATION

BENEFITS

Word Processing/

Data Managenent

Incorporate reports generated by EBMS Management

documents produced with a word processor.

into

Word Processing/

Spread Sheet

Incorporate spread sheet calculations (either total or partial) into reports, memoranda, and other documents

produced with a word processor.

Word Processing/

Graphics

Incorporate graphs into reports and other documents. Note:

suitable only where single output device produces adequate

quality of both text and graphics.

Word Processing/

Specialized

implication

Incorporate results of specialized applications directly

into documents under preparation without need to retype.

Data Management/

Graphics

Plot (bar, pie, scatter, other) data in selected (or all)

records.

Data Managonent/ Transmit (or receive) data for inclusion in files.

CcHimunication

Data Managonent/ Entry, maintenance, modification, searching, sorting of

Specialized data records can be handled by file manager, actual

i^lication specialized analysis performed by other application

programs (either written in data manipulation language of

IBMS or as separate program in other HOD

.

88
Chapter 4 - Microcomputer i^lications

TABLE 4-9 (continued) . APPLICATION INTEGRATION

APPLICATION BENEFITS

Spread Sheet/

Gra0iics

Presentation of spread sheet results in an easily

understood form. This capability is useful when dealing

with larger tables or when presenting results to others

less involved with the details of the calculations.

Spread Sheet/

Communication

The ability to transmit spread sheet results or take data

from larger systems (e.g. econanic data from public access

computer networks) for use with a spread sheet model.

Spread Sheet/ Ability to take results of specialized program (e.g.

Specialized solution to a set of partial differential equations) and

Application perform sinple parametric studies on results without need

to rerun a complex application.

Gra^iics/ Transmission of graphic material to other users. Note:

Communication alternative for data plots is transmission of numerical

data in ASCII format and replotting at ronote site.

However, for diagrams, designs, and other non-data

oriented gra^iics, this may not be practical.

Graphics/ Direct plotting of results of specialized application.

Specialized

/plication

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Chapter 5 - Management Issues of Microcomputers

CHAPTER 5 - MANAGEMENT ISSUES OF MICROCOMPUTERS

This chapter discusses several topics on microcomputer usage and managonent.

Section 5.1 discusses the motivation for the use of microconputers and their

utility to the four user classes described in Chapter 3. Section 5.2 lists

factors affecting the costs of microcomputers, 5.3 discusses the risks in

their use, and 5.4 describes some of the means of avoiding or reducing theses

risks. Finally, section 5.5 lists currently available sources of

microcomputers available to Federal users.

5.1. MDTIVATION FOR USIN3 MICROCOMPUTERS

The demand for microcomputers in the United States is large and growing. A

major financial periodical [BUSW82] estimates the ccxnbined 1982 sales of the

four market leaders at $5.5 billion (including microcomputer hardware,

software, and subsidiary products). Estimates of 1982 shipments of personal

computers vary from 860,000 to 2 million (depending on whether home or entertainment systems are included) and a 500% increase is predicted by 1986

[DODG82]. Microcomputer usage in large organizations is growing even faster

than the general market. Most researchers predict that government and

corporate demand for microcomputers will equal or exceed the rest of the

market by 1986 [DODG82].

A driving force behind this rising demand is the need to increase the

productivity of white collar workers who now make up approximately one half

of the United States workforce [TEGE83]. One study quoted by Goldfield

[GOLD83] estimated the productivity gain of this sector at 5% over the last

decade while the corresponding increase for industrial productivity was 83%.

The Federal government has even more motivation to use microcomputers.

According to a recent General Accounting Office study [GA382], white collar

workers comprised 80% of the Federal work force and cost $81 billion in 1980.

Table 5-1 shows examples of how microcomputers can be applied to the tasks of

Federal workers. The low cost of hardware and standard software applications

and the fast response possible with microcomputers (especially for highly

interactive tasks) make them promising vehicles for increasing worker

productivity in a variety of functions.

In addition to individual productivity gains, microcomputer installations can provide more global benefits to agencies. Some of these include:

an increased level of operational reliability where compatible systems

are installed. Work can be moved to another computer if one system

fails

joint development and sharing of applications

gradual updating of inappropriate or obsolete equipment (updating of a central computing facility is always a high risk activity)

It is therefore not surprising that some Federal agencies have begun to

procure microcomputers in quantities of hundreds or thousands, and that these

systons now constitute a significant portion of Federal computer procuronents.

90
Chapter 5 - Managonent Issues of Microccanputers

In August, 1982, 45% of the data processing announcements in the Commerce

Business Daily» the most comprehensive single source of Government

procurement activity, were for microcomputers and an additional 27% were

for minicomputers whose performance capabilities were in the range of

contemporary microconputer systems. Because of their low unit prices, many

microcomputer purchases were not opened to competitive bidding (this

practice is allowed under current Federal ADP procurement regulations).

Thus, the level of purchases is probably even higher than suggested by these

figures.

CLASS

TABLE 5-1. APPLICATIONS OF MICROCOMPUTEEIS TO CLASSES OF USERS

APPLICATIOJS

CLERICAL

ADMINISTEyVTIVE

PROFESSIONAL

TECHNICAL

Document preparation

Data entry

Preparation of routine budget and fiscal reports

Document preparation

Planning and budgeting

Contracts administration

Personnel administration

Graphics for meetings and presentations

Document preparation

Bibliographies

Data management

Statistical and profession-specific calculations

Graphics for reports and presentations

Laboratory autcsnation

Terminal emulation (for interaction with larger

computers)

Other specialized applications

Software development and validation

Laboratory automation

Computer communication

Automated testing and data collection

Terminal onulation

Document preparation

Bibliographies

Data management

Other specialized applications

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Chapter 5 - Management Issues of Microcomputers

5.2. COSTS OF MICROCOMPUTER SYSTEMS

Although the cost of the microcomputer hardf^are and software is relatively

low, the cost of effective implementation in a large organization can be much

higher. The system costs start at the time the procuronent is initiated and

continue throughout its life. Major cost components include hardware,

software, procurement, site preparation, instal lation and implementation,

training, supplies, maintenance, and correnunications. Table 5-2 describes

these components in greater detail. It is quite reasonable to expect that the

total cost of the system will be several times that of the initial hardware

and software costs.

TABLE 5-2. MICROCOMPUTER COST FACTORS

CLASS ITEMS

Procurement Requirements specification

Consultations

Purchasing process (include preparation of RFP and

evaluation of bids if relevant)

Hardware Basic System (CPU, memory, disk drives)

CRT terminal (s)

Additional disk drives (e.g. hard disk)

Printer (s) (dot matrix and letter quality)

Modem

Attachments and accessories (additional RAM,

interfaces, cables, etc.)

Additional peripherals (plotters, joysticks,

digitizers, etc.)

Specialized interfacing costs (consider when adding

any serial device)

Furniture (CRT tables, chairs, printing stands, etc.)

Noise Hoods

Electrical power conditioning equipment and battery

backup units (as required)

Software Operating system (s)

Purchased application software

Software installation and modification

Custom developed packages

Cost of updates

Ongoing software support costs

(more)

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Chapter 5 - Management Issues of Microcomputers

TABLE 5-2 (continued) . MICROCa'lPUTER COST FACTORS

CLASS ITEMS

Site Preparaticai

Conversion

Implementation and

Installation

Training

Supplies

Maintenance

Air conditioning

Electrical work

Installation of Cables

Alteration of offices and work areas (including

carpentry work)

Lighting changes (desk lights, curtains, etc.)

Lost production time during site preparation

Inputting data to new system

Modifying (or rewriting) programs

Setting up files

Managing conversion effort

Lost production time during installation

Cost of running parallel operations

Planning and supervising costs

Freight Charges

Keeping track of the location of all hardware and

software components

Cost of training and supplemental materials not

included with package purchases

Lost production during training

Cost of providing space for on-site training

"Refresher" courses and ongoing training for new

employees

Disks

Paper

Ribbons

Anti-static mats and sprays

Cleaning supplies

Glare screens

Paper stands

Cost of maintenance contracts (if available)

Cost of transporting systems to repair depot (if on

site service is not provided)

Cost of spare units

Lost production time

Lost production data

Coimunications Telephone charges

Cost of components (cable, interfaces, software)

Cost of network installation

Outside network charges

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Chapter 5 - Management Issues of Microcomputers

5.3. RISKS OF MICROCOMPUTERS

Microcomputers create two types of risks: technical and organizational.

Technical risks are related to the inability of the system to function

according to expectations. Organizational risks arise because of the prdDlans

in implementing and managing microcomputers in large organizations.

5.3.1. Technical Risks

The technical risks of microcomputers can result in both total failures and

inadequate implementations. Although these problems also affect larger

computer systems, microcomputers are unique because they are installed in

large numbers and in settings where expert support is not readily available.

The failure of microcomputers to deliver the expected performance can be due

to any combination of the following causes:

Improper Specifications or Requirements

The most obvious reason for a system to fail to live up to

expectations is that users did not specify exactly what performance

was expected. Requirements and resultant specifications must

consider issues ranging from organizational policies to the

placCTient of electrical outlets, and must be understood by all those

involved with the system. In larger and more expensive conputers,

' generation of functional requironents and systems specifications is

an important part of a long computer selection process and is

performed by knowledgeable personnel. However, the lew prices of

microcomputers make such a process more difficult to justify

economically despite the fact that it is still necessary.

Less Capable Vendors

Low profit margins and high volume have limited the ability of

vendors to provide the required level of technical competence for

microcomputer sales personnel. The high rate of innovation

exacerbates this problem because no time is available to orient or train the sales force for each new product. These circumstances

have resulted in a greater frequency of misunderstood

specifications, product misrepresentations, and inadequate post- sale

support.

Less Technically Knowledgeable Users

The proliferation of microcomputer hardware and software has not

been accompanied by a corresponding increase in the number of

technically qualified personnel. As a result, the ability of

Federal users to resolve system problems is limited. Areas of

particular concern include multivendor systems, communications,

software installation, and customized applications. The only way to

resolve these difficulties may be to discard an entire systoiu

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Chapter 5 - Managonent Issues of Microcomputers

Hardware Reliability

Although the entrance of major computer manufacturers into the

microcomputer market resulted in the establishment of a higher

standard for manufacturing quality and hardware reliability, users may still face the possibility of getting an unreliable and

unmaintainable system. A way to reduce this risk is to procure

systems from qualified suppliers and major manufacturers.

Software Problems

Problems in software may arise from incompatibility with hardware or other installed software, programs not meeting user expectations, or poorly written code. Because of widely used operating systems,

microcomputers may actually offer users better protection than

larger systems for standard applications (i.e. word processing,

spread sheets, data management, graphics, and communications)

unsuitable software can simply be replaced with a competing product.

Unfortunately, these problems can not be so easily resolved in

specialized applications and custon developed code. The scarcity of

qualified microcomputer software experts coupled with the relatively

limited software development and debugging tools available for

microcomputers contribute to the problem.

Interfacing Problems

The difficulties of connecting peripheral devices such as printers,

plotters, and pointing devices to "standard" ports has been

discussed in Chapter 2. Microcomputer users are particularly

vulnerable because multivendor systems are quite common. As was the

case in software and hardware related problons, the relatively low

level of expertise that can be brought to bear on an individual

system is often insufficient to solve the problem.

As was noted in Chapter 5, establishing communication links between

a microcomputer and other computers can also pose problems.

Difficulties can arise on the hardware level, the software level, or both, and their resolution can be both time consuming and costly,

5,3,2. Organizational Risks

Even if microcomputer installations are satisfactory from the individual

user's point of view, they can pose a risk to the organization as a whole.

Most of the issues relate to control over information resources within the

organization. However, there are additional concerns over mastering the new

technology and the change in the nature of the centralized computing function.

The following is a partial list of risks which agencies may face while

implementing microcomputers:

Uncontrolled proliferation of microcomputers

The presence of a large number of inccropatible microcomputers within

a single organization presents an unmanageable situation to those

95
Chapter 5 - Management Issues of Microcomputers

responsible for maintenance, training, and support. The problon may

be exacerbated if there is a need to interconnect these systems to

internal minicomputers or mainframes.

Unfortunately, the adoption of organizational guidelines and

policies addressed at resolving this problon is not risk-free. A

poor choice of computers and the way in which they are

interconnected could freeze an entire organization into an obsolete

technology. A mandatory standard microcomputer system may be such a

poor fit to the needs of a significant number of users that their

ability to perform their tasks is impeded. Conversely, a standard

^stem may be overly elaborate and thus a wasteful investment.

Loss of control over data

The growth of microcomputer use complicates the control over

generation and disposition of machine readable data. This issue may

actually preclude the use of microcomputers in agencies dealing with

confidential or sensitive information. Even if the data being used

on the microcomputers are not so critical, end users may not

understand the need to back up files and validate their data.

Data in Federal agencies are subject to acts of Congress (e.g.

Brooks Act, Freedon of Information Act, and the Paperwork Reduction

Act,) and rules issued by the General Accounting Office and the

Office of Management and Budget [GAD82]. Agencies must comply with

these regulations in order to ensure the integrity and security of

data collected and generated by the Government [BRAI83]. If all

records are in the hands of the end user in the form of (erasable)

magnetic media, there can be no central access to that information

and no audit trail of what was done.

Loss of control over programs

Two problems concerning software usage on microcomputers are

unauthorized duplication and undocumented and unvalidated usergenerated applications. The presence of compatible systems makes

software interchange both necessary and desirable. However, it also

facilitates the generation of copies for use on systems other than

those for which the software was licensed. The legal liabilities of

such activities have not yet been definitively determined. However,

at the very least, agencies would probably have to pay for all

unlicensed copies, an unanticipated expenditure which can severely

limit system growth plans.

Undocumented applications are useful only to the author. Their

future value is lost, implications used for accounting purposes or

for making important decisions should be validated. Unfortunately,

the need or procedures for such validation may not be understood by

the program writers and users.

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Chapter 5 - Management Issues of Microcomputers

T^ngAQP b^twg^n MiCFQComputer Usei;s

^

jtiie centralized computing

The diffusion of control over information resources fran a centralized department to individual users will cause a number of

changes. Programmers and analysts who formerly worked on

mainframes may have to start supporting microcomputers with a resultant need to undergo retraining and a new period of learning.

In addition, microconputers may compete with other data processing

resources for budget and manpower allocations within the

organization. Widespread installation of microcomputers could

reduce demand for some types of data processing services offered by

the centralized department. This problem has received increasing

attention by a number of authors [STJ082, DODG82, DODG83, FERR82,

HCXJS82, CORT82, 0EIAR82, BLAN83].

5.4. PEIEVENTION OF PROBLEJyiS

Preventing the problems listed in the previous section implies a recognition

of the risks and explicit actions to reduce or avoid them. Mong the actions

that an agency can take are the institution of microcanputer policies, su^^rt

provisions, maintenance planning, and development of a training program.

These tc^ics are discussed in this section.

5.4.1. Microcanputer Policies

The primary goal of using microcomputers in an agency is to further its

organizational goals. Microcomputer implementation policies embody the

strategies for achieving this goal. These policies could, but do not have to,

suit the interests of individual users, but the user community as a whole

should benefit from policies which complement the overall mission of the

organization. The degrees of latitude in these policies may range from those

which encourage the installation of many different types of systems to those

which severely restrict the freedom of prospective purchases to a single

vendor. Agencies with sharply differentiated applications and technically

capable personnel may have policies which encourage experimentation with a

variety of systons; those with limited resources and more uniform applications

may wish to enforce a more restricted policy.

Areas which should be addressed in the organizational microcomputer

implementation policy include:

Standards for common interfaces, operating systems, processors,

languages, data formats, and other corr^atibility-related areas

System architectures (i.e. computers and the ways in which they are

interconnected) that allow for growth at the individual user level and

across an organization to support shared resources, multiple user

networks, and new technologies

Leverage of volume purchases to obtain preferential suj^rt from vendors

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Chapter 5 - Management Issues of Microcomputers

Internal support to assist users with problans and to reduce duplication

of efforts.

A good policy will allow for flexibility to meet changing organizational

requirements, growth of demand, and the fast pace of technological

innovation. From the user perspective, good organizational policies wcxild

ensure a consistent, high level of support and clear procedures for obtaining

approval of proposed installations.

The implementation of a microcomputer policy should fit the operating style of

the organization. Thus, it can range fran an informal system of giving advice

to users to formal controls with technical and consulting support. In a small

or highly decentralized agency with no resources to provide support, informal

advice to users may be the only feasible policy. In larger or more

centralized organizations, specific individuals can be designated to implement

a policy that includes selection guidelines, recommended vendors, standards,

and compliance incentives. In extreme cases where tight central control over

the use of information and systems is essential, a control function can be set

up to oversee and support all installations.

5.4.2. Support Provisions

Users of microcomputers may need a variety of types of support ranging from

simple help in the physical installation of equipment to technical and

analytical support in creating complex applications. Some users are

sufficiently knowledgeable to work without any support; others may require

extensive training and ongoing assistance. Federal agencies can choose to

provide some or all of the required support internally, they can depend on

the systons' vejndors, or they can turn to third parties such as consultants,

annaller organizations may not be capable of providing support because of both

staffing and cost considerations; larger organizations may already have

support staffs established which could add microcomputers to their

responsibilities. Because of their ongoing activities in support of other

customers, responsible vendors may be more capable of responding to

intermittent requests for assistance. Special requirements such as remote

installations, an unusual application, or one-time group training may be best

handled by consultants, who can provide a higher level of support for

specialized applications.

The support needs of microcomputer users can vary substantially with the

applications. Systems that are brought in for basic stand alone applications

(e.g. light typing or spread sheet-type problems) will result in relatively

light demands on the organization. However, the use of a specialized

internally developed program (e.g. a custom tax package for tax auditors)

causes much greater demand on the organization both in the implementation and

maintenance. As a result more support and control may be required.

5.4.3. Hardware Maintenance and Repair Planning

Planning for microcomputer maintenance is necessary in order to minimize down

time and the resultant significant losses in productivity. Two major choices

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Chapter 5 - Management Issues of Microcomputers

involved in hardware maintenance and repair planning are where to perform the

repairs and by whan the repairs should be done.

Possible repair locations include the site at which the systems are installed,

a local service location, and a remote service location. On site repairs

require that the service technician have an adequate supply of spare parts,

test equipnent, and tools at either the site or rapidly accessible location.

Local service centers require that the system be brought in for repairs;

central service centers require that the equipment be shipped to a distant

location.

The actual repairs can be done by an employee of the user organization, the

vendor, or third party repair service. When the user organization takes the

responsibility for maintenance, they take on the whole complex set of problems

of running a repair service which includes maintaining inventories of parts,

test facilities, and keeping an adequate staff. The greater the range of

systems to be supported, the more canplex the service requirements.

Factory service technicians may be the most straightforward method of

providing support; where warranties are involved, the vendor may require all

service to be done by factory authorized personnel. Use of factory personnel

may not be possible if the equipment is purchased from a smaller or newer

company which does not support equipment at distant locations. Generally,

service personnel from hardware vendors only service their own equipment.

Thus, multivendor systems are often difficult to service by means of factory

personnel.

Third party repair organizations can range from a single person working in the

back of a computer retail shop to a nationwide organization able to service a

wide range of equipment brand names and types. This may be the best way to

handle multivendor systems. However, as with internal repairs, warranties may

be voided.

Additional issues concerned with hardware repair include hours (typically 8-5

Monday through Friday), charges for off-hour service, guaranteed response time

and repair time, replacement of an entire system if repeated repairs are

unsuccessful, loaner systems for use while repairs are being made, and the

stockpiling of backup systems. In general, the more critical the syston, the

more service is required.

5.4.4. Training

Training is often necessary to enable users to gain the full benefit of their

systems and applications. Even if users are capable of reading and

understanding the documentation accompanying their systems, training can

frequently be econonically justified by shortening the learning period and

conveying information which may not be contained in the documentation.

Training can be provided by the vendor or the user organization in any of the

following ways:

Self-paced instruction manual

Computer assisted instruction

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Chapter 5 - Management Issues of Microcomputers

Audio and/or video tapes

Class Instruction

Individualized Instruction.

In general, the cost of training increases in the order listed above.

The effectiveness of any of these methods depends on the quality of the

instruction and material, the skill base of the trainee, the complexity of the

package, and the application requirements. The amount of time devoted to

training depends on projected use of the system or software package. If a user intends to rely on a particular system as a key tool in doing daily work,

then a substantial canmitment of time to training may be warranted.

Other factors to be considered in the development of a training program

include availability to users in ronote locations, hours available (swing and

night shift employees may not be able to come in during the day), validation

of success with provisions for follow up of in problem areas, advanced skills

training, ongoing trouble shooting, and special application training.

5.5. SOURCES OF MICROCOMPUTERS

This section describes sources of microcanputers available to Federal users. Section 5.5.1 describes microcomputer procurement through the General

Services Administration. Section 5.5.2 discusses procurement through the

internal entities of Federal agencies, and section 5.5.3 discusses external

sources of microcomputers.

5.5.1. The General Services Administration

The General services Administration has undertaken two new initiatives to

facilitate the purchase of microcomputers by Government Agencies: Schedule C

and the Federal Information Product Center. Federal Supply Code 70 (automated

data processing equipment) Schedule C is a specially negotiated pricing

schedule between the GSA and large volume vendors of microcomputers which

contains the lowest prices available to the Government under most

circumstances (exceptions are very large lot purchases by individual

agencies). Agencies place their orders with GSA which in turn combines the

orders, places them with the appropriate vendors, and then distributes the

microcomputers to the ordering organizations. The Federal Information Product

Center is a retail-store like setting operated by a contractor in Government

supplied space. The contractor acts much as any retail conputer store, i.e.

supplying microcanputers, general training classes, specialized training and

consulting (on a fee basis), and repair services. As a result of this

arrangement, it is expected that the Government will get better prices than

generally available in retail establishments while providing users with the

convenience and level of service that such stores can provide (see section

5.5.3)

.

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Chapter 5 - Management Issues of Microcomputers

5.5.2. Internal Sources

An alternative to GSA schedules is the centralizing of microccmputer purchases

at the agency (or even regional) level. Internal organizational entities can supply microcanputers in a number of ways including the following:

Internally Developed Microcomputer

If a large number (on the order of thousands) of microconputers are

to be installed, economies of scale may favor the internal

development and support of a microcomputer. The use of a standard

bus can reduce costs and enables users to install specialized

component boards in areas such as laboratory automation and data

collection. Common components can be locally stocked for readily

available spares with a consequent reduction of repair times and

cost. If canmon microprocessors and operating systems are used, a large base of software is available.

Centralized Purchases of Microcomputers from a Single Vendor

Ihis is the most easily implemented, justified, and certain approach

from the procurement and impl orientation point of view. Even if an external supplier is used, agencies may consider the use of

Government onployees for all support activities to increase system

availability and performance and to reduce the risk of being left

without support should the vendor abandon the product line.

Centralized Purchases of Several Conputer Product Lines

The purchase and support of several microccmputer lines reduces the

risk of obsolescence and dependence on a single supplier while

sacrificing some of the standardization advantages noted previously.

This approach is also functional in situations where microconputers

are being used in settings with widely varying user requirements

(e.g. document preparation and laboratory autcmation)

.

5.5.3. External Sources

The use of external sources provides the widest choice at sane penalty in time

and paperwork. It is therefore justified when making large procurements or pilot purchases. Federal acquisition regulations provide three purchasing

alternatives: GSA Federal Supply Code 70 Schedule A, competitive

procurement, and noncompetitive procurenent with sole source justifications.

GSA Schedule A is a list of prices that have been offered to the Government by

vendors of microcomputers. (Generally, these prices are discounted from list,

but further discounts are sometimes possible by means of direct negotations.

Competitive procurement is a more complicated process which involves

announcing the procurenent in the Commerce Business Daily, allowing vendors an adequate time to respond, and then evaluating the bids of all respondents.

The process may take several months, and is best used for larger procurements.

Noncompetitive procurement is possible if one source is clearly more

qualified. Justification for sole source procurements must be provided and

approved, a process which may also cause a delay of several months. An

101
Chapter 5 - Management Issues of Microcomputers

example of a case where such a procurement is justified is the enhancement of an installed microcomputer-based local area network.

Microcomputers, software, peripherals, and other accessories can be obtained

from a variety of sources including manufacturer's sales representatives

system integrators, retail computer stores, consultants, direct mail, user's

groups, and related sources.

Manufacturer's sales representatives have been the primary source of larger

computer systems, and continue to be a source for large volume purchasers of

microcomputers (such as Federal agencies). The primary advantage of buying

through these representatives is the ability to maximize agency influence

resulting from large orders. Interaction with these representatives can

facilitate the obtaining of proper support, favorable resolution of hardware

and software problems which are (or possibly are) the fault of the

manufacturer, early knowledge of new or planned product announcements, and

ability to obtain very specialized and expert advice in new or demanding

applications development. However, because of the costs involved in

maintaining a direct sales force and providing the additional user support,

manufacturer's representatives may not provide the lowest price for systems

and software. Moreover, the fact that sales representatives are largely on

commission may result in overly optimistic claims of equipment capabilities

and the overlooking of more cost-effective alternatives.

System integrators, also known as OEMs (Original Equipment Manufacturers),

provide complete systems based on components from a number of manufacturers.

OEM organizations have been a prominent distribution channel for

minicomputers, systems which both required a significant amount of technical

support and provided relatively high unit profits. In microcomputers their

major role seems to be evolving into serving as marketing and distribution

entities for smaller manufacturers which produce high-end systems and can not

afford their own sales organizations. Thus, the hardware offered by these

sources may provide some unique capabilities such as multiuser capabilities,

more advanced microprocessors, and more sophisticated operating systems.

However, these systems are generally not the popularly recognized (and highly

marketed) brand names, and their greater complexity and smaller production

runs will probably result in more operating problans and the consequent need

for greater support. Unfortunately, continued support of such products

depends solely on the viability of both the system integrator and manufacturer

and their commitment to a product line which may no longer be sold. In the

rapidly changing and highly competitive world of microcomputers, this

comonitment is far from assured.

Retail Computer stores are the most prominent distribution channel for

microcom.puters; estimates of their portion of sales range as high as 70%

[FINK83]. Three major types of computer stores can be defined: manufacturer

owned retail outlets, franchises, and independents. Manufacturer owned retail

outlets carry only a single product line and will not provide discounts for

small quantity purchases (unless the particular product is being

discontinued). However, because of the organizational ties, these outlets

provide the highest levels of product availability and support — in some

cases, they are the only sources for certain products. Franchise stores deal

with several lines of products, and are generally required to conform to

102
Chapter 5 - Management Issues of Microcomputers

minimum standards of service and support. Because of these standards and

their policies of selling the most popular ^stems, they provide a relatively

low risk means of purchasing systems. However, prices are generally dictated

by franchise-wide policies, their product offerings are limited to a few best

sellers in both hardware and software, and these dealers may have limited

abilities in the areas of technical support and service. Independent computer

stores comprise the largest and most heterogeneous portion of the retail

distribution channel. Sane independent retailers are quite similar to OEMs in

their high level of support — the only difference may be the existence of a store front. Others provide discount prices as a means of competing against

the better funded franchises and manufacturer-owned outlets. Most also rely

on personalized service, support, and technical capabilities to attract

follow-on business and referrals.

The effectiveness of all types of computer stores for the sales and support of

microcomputers can be seen in the fact that many large organizations procure

their systems through these outlets [BUSW82, FINK83]. Motivations for Federal

agencies to use these sources include policies encouraging the use of small

local businesses, the ease of procuring systems, and the level of support

provided to major clients. However, there are scsne drawbacks to the use of

computer stores as the primary microcomputer procurement and support source. The unstable, capital intensive, and highly competitive environment in which

microcomputers are manufactured and sold is not particularly conducive to

small businesses, and their long term survival is by no means assured.

Some microcomputer consultants have become sources of microcomputers through

their activities on implementing systems in small and some medium sized

organizations. Their operations are quite similar to those of OEMs and value

added dealers, but their comnitments to a particular manufacturer may be less

formal, and therefore more subject to change. Under the best circumstances,

consultants with expertise in the application area and good relations with

various manufacturers and distributors can provide the most cost-effective

means of implementing systems. Under other conditions, custoners have to pay

for the time to learn the particular application, and the consultant may not

be sufficiently knowledgeable to make the correct decisions. Because of the

relatively small number of independent microcomputer consultants, this channel

is relatively unimportant for most purchases. However, if many systems in a specialized application are being procured, a consultant with a good

reputation and relevant expertise may be the most appropriate source.

Mail order is generally the means of obtaining the lowest purchase price for

microcomputer systems, peripherals, and software. It is also the one with the

highest risk and lowest level of support. The optimal use of mail order

sources is the purchase of products already in use within the organization.

In these cases, the compatibility and performance of the products are known,

and testing of ordered products can be easily performed by comparing with

units currently in use (it is not uncommon for both hardware and software

shipped through normal mail or package handling companies to be defective when

it arrives). Knowledge of mail order prices is also important in conducting

negotiations with other sources of microcomputers. The ability to quote a lower price from a mail order source is often the most effective means of

getting a lower price from a more direct source.

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Chapter 5 - Management Issues of Microcomputers

User groups and "communities" which have congregated on various private and

government networks are a source for a variety of public domain software,

some of which is quite powerful. For example, one of the most sophisticated

RS-232/modem microcomputer communication packages is readily available from

the AEIPANET, and the New York CP/M User's Group has some 20 disks of software

available for the cost of the duplication, shipping, and handling.

Unfortunately, the quality of such software is not uniform, and direct contact

with the author (if known) is the only source of support. Thus, use of such

software requires a significant investment of time and expertise, and is not

recommended for non-technical users. On the other hand, if a public domain

software package can be adapted for use on a large number of Federal systems,

it may be preferable to the purchase of proprietary packages.

10^
Chapter 6 - Conclusions

CHAPTER 6 - CONCLDSIONS

Section 6.1 discusses recanmendations to end users and section 6.2 lists areas

where further guidance and standardization activities are desirable.

6.1. SUMMARY OF KEY POINTS

All readers considering the implanentation of microcomputers in their agencies

should be aware of the following:

Microconputer Technology is Advancing at a Rapid Rate

The performance advances made by mainframe manufacturers in two

decades have been made by microcomputer manufacturers in five years.

The unprecedented rate of new product offerings and a changing

market require full-time personnel for effective monitoring. Users

attempting to select microcomputers should either be cognizant in

the current state of the technology themselves or use the services

of those who are — especially for large procurements. The cost of

such expertise is justified by the value to the organization in

avoiding the risk of inadequate systems rather than the price of the

equipment and software being procured.

Microcomputers Require Constant Support

Unlike typewriters, copiers, or some other office equipment,

microccmputers require continuous support in the form of training,

maintenance, and new applications. The major objective of

organizational microconputer policies is to ensure that users have

such support. Unsupported systems soon become a liability to the

organization.

Application Software Should Be the Basis for Microcomputer System Selection

Although intuition suggests that the computer hardware is the

driving force behind computer acquisition, it is actually a

secondary consideration. Nearly all 'business' (as opposed to home

oriented) microcomputers have adequate computation capacity for

roost Government applications, but not all are canpatible with the

applications software which are required by users. Because the

software defines the functionality of the computer, it drives the

procurement decision.

Successful Inplementation of Microconputers Requires a Broad Perspective

A broad range of organizational, psychological, ergonomic, hardware,

and other issues must be considered. This large number of factors

may result in conflicts or incanpatibilities which must be resolved

by re- iteration of some of the steps in the selection procesa The

investment of time in the system procurement phase will result in

substantial benefits over the syston life.

105
Chapter 6 - Conclusions

User Responsibility and Control

A significant difference between microcomputers and mainframes is

the primary focus of responsibility: for mainframe computers,

primary responsibility and control is placed within a dedicated

department; in microcomputers, the end user has primary

responsibility.

This change in the focus of responsibility poses a challenge to

traditional ideas on the management and control of computing

resources in large organizations. Personal computers are

controlled by individuals, not data processing departments.

Although this control has resulted in greater responsiveness to

individual interests, it has caused significant problems for

managers of information resources in Federal agencies. As noted in

Chapter 5, this problem is not simply a matter of jurisdictional

disputes; Federal statutes require the oversight of Government data

processing equipment (including personal computers) to prevent

fraud, waste, and abuse. Thus, although end users now have

unprecedented access to canputers, they are subject to controls and

must be aware of the larger context in which they are working. This

context consists of both technical aspects — i.e. compatibility

with existing communication systans, mainframe computers, or local

area networks — as well as organizational aspects — i.e.

managenent of data security, data integrity, and other issues.

User Interaction

Users can control all aspects of the computer operation and can

therefore tailor computer operations to suit their own needs,

eliminate delays, and reduce costs. However, inexperienced users

also have an unprecedented degree of interaction with a very complex

system. Because of the limited expertise of most users, the syston

must provide a "friendlier face" to users (i.e. operators) than in

larger systans.

This interaction causes a number of differences in the way data

processing occurs on microcomputers. In larger systems, a number of

individuals with specialized knowledge of system operation, syston

programming, application programming and data entry are involved.

On a microcomputer these tasks are performed by a single individual.

Although the tasks are significantly simpler than the corresponding

ones on larger systems, end users must acquire a significant body of

knowledge in order to use these systems effectively. It is ironic

that the breadth of knowledge required of millions of

unsophisticated end users is not required of experts on the larger

systems.

Performance

Microcomputers typically have smaller memories and slower central

processing units than their larger counterparts. Thus, some

106
Chapter 6 - Conclusions

applications which run on larger canputers (e.g. large scientific or accounting programs) cannot be easily converted to microcomputers.

Security

Because a single user can have exclusive control of the entire

microcomputer system, microcomputer security is often less of a problem than security on mainframes. Users can physically ronove

and restore all critical data during the course their sessions, and

can store removable mass storage devices such as disks or tape in

the same manner as confidential documents and film. However, the

ability to easily transport machine readable data makes

organizations more vulnerable to the misuse of data by employees

with access authorization. Covert movement of a single disk or tape

across a security boundary to a compatible unauthorized system is

much easier than the movement of documents or the larger disks found

on minicanputers and mainframes.

Ccmmon Data

Data sharing is useful in administrative, legal, technical, and

other settings. Unfortunately, single-user microcomputer systems

are not amenable for communal access to a single data file.

Although multiuser systems allow common access to a single data

storage device (e,g. a hard disk), most do not have software which

allow common simultaneous access to a single file.

6.2. USEFUL AREAS FOR GUIDELINES AND STANDARDIZATION ACTIVITIES

Desirable guidance and standardization activities are discussed according to

the user classification of Chapter 3.

6.2.1. Clerical Users

Useful guidance pertaining to clerical users can be provided in the

following areas:

Erqoncxnic Design of CRTs and Keyboards

As has been noted previously, attention has been focused on the ergoncmic

aspects of CRTs and keyboards and their psychological and physiological

impact on operators. Ketch [KETCH83], Bond [B0ND82] , and other authors

have suggested a number of useful criteria, although all point out that

they are based more on intuition than on definitive research results.

Continued investigations in this area are in progress.

Integration of Microccmputers in Larger Systems

Standardization activities in the area of office autcmation will aid in

the integration of microcomputers into larger systems including the

ability to communicate with other computers and to process data files

produced by other software. Recent efforts from NBS include guidance in

107
Chapter 6 - Conclusions

the setting of requirements [^BS80], coded character sets for text

processing [1SBS81], and message interchange format standards [WATK82].

Application Software for Clerical Users

Clerical users can benefit from microcomputer software in the areas of

word processing, data entry, and ccanmunication. Guidance in the setting

of requirements and evaluation of existing systems is beneficial to

these personnel.

6.2.2. Managerial and Administrative Users

Useful guidance to managerial and administrative users can be provided in the

following areas:

Appropriate Usage of Microcomputers

Guidance on the appropriate use of microcomputers will maximize benefits

and reduce organizational risks associated with their introduction. As

experience with managerial and administrative usage of microcomputers

increases, knowledge of the important organizational variables which

determine appropriate and inappropriate microcomputer uses will become

available. Until that time, it should be recognized that extensive

commitments to microcomputer use in applications where there is no past

experience (in either the public or private sector) carries some risk.

Guidelines based on past successes and failures are frequently published

in trade journals [BLAN83, GULD82, MCCU82, OHAR82, ROMA83, STJ082,

SMEJ83, W0HL82, and others].

Office Automation

Administrative users will benefit from guidelines in office autanation

and in integrating microcanputers into such systems in a manner similar

to clerical users [G/^82, BECK82, MEYE82].

Communication with Larger Systems

Administrative users can benefit from the ability to retrieve information

fron a centralized ccmputing resource for local manipulation and display.

This capability involves communication standards on a technical level

as well as guidelines in the appropriate use of this information on the

organizational level.

Application Software for Administrative and Managerial Usage

At least five key microcanputer application software areas are useful to

administrative and managerial users: word processing, data managenent,

spread sheet analysis, graphics, and communication. The greatest

benefit of such software can be obtained if new products are tested and

evaluated in a centralized Government agency. In addition, guidance on

the setting of requirenents in new application areas is also useful.

108
Chapter 6 - Conclusions

Additional software related to specific functions (e.g. project

management or accounting) can be useful if it conforms to current

policies and guidelines. Standards for accounting software have been

stated by the General Accounting Office [GAD78], and numerous reporting

formats for project management have been defined by a variety of

Government agencies. Activities in the areas of certification of

software to fulfill these requirements on the parts of individual

agencies or centralized functions would be particularly beneficial to

managerial users.

6.2.3, Professional Users

Professional users can benefit from guidelines and standards in the following

areas:

Communication with Larger Systens

The ability to use software and data residing on mainframes (e.g.

statistical analysis packages or economic data) in conjunction with

software on microcomputers (e.g. spread sheet packages, graphics, or data

management systons) can result in large productivity increases for these

workers. Thus, these users will benefit from standards in computer

communication including both low levels (i.e. those related to the

control of the data flow and the actual physical interconnection) as well

as on the application level (e.g. converting data from a mainframe into a format usable by microcomputer applications).

Microcomputer Application Software

Professional users will benefit from standards in the five general

application areas given for administrative users. In addition, these

users will benefit from a central source of information and guidance on specific packages in medicine, agriculture, earth science, social

science, and other areas.

6.2.4. Technical Users

Technical users will benefit from guidance and standardization activities in

the following areas:

Software Development Practices

Disciplined software development practices may still be a novel subject

to many microcomputer programmers. Recently announced microcomputer

software development systems which are based on either specialized

microcomputer hardware or minicomputers may aid in this process.

However, the field is still relatively new, and additional conceptual

work is necessary. A companion report [NBS83a] discusses this area.

109
Chapter 6 - Conclusions

Lancfuaqe Processors

Standards for microcomputer language processors (i.e. compilers and

interpreters) currently lag behind the state of the industry, and, as a

result, the dominant products often become the de facto standards. In

sane cases, standards for compilers used on larger systons can serve as a useful basis for certification. Thus, the General Services

Administration has recently certified several FORTE^AN, CXBOL, and BASIC

implementations for microcanputers based on their standards for mainframe

compilers

.

Communications

The importance of communications for all user groups has previously been

stressed. However, the existence of standards in this area is

particularly beneficial to technical users who, in many cases, are

responsible for building computer networks and writing the communication

software. Current work by the IEEE, the ISO, and hardware vendors may

have a large impact on this area in the near future.

Data Formats

The ability to exchange data between two processes (on either a single

computer or two separate systons) depends on a uniform file structure and

data format. Work in this area is currently underway at NBS [WATK82],

and several microcomputer software vendors have published their own

standards for the transmission of spread sheet and graphics data.

However, with the exception of the ASCII character set, this area remains

largely unresolved, and additional work is necessary.

Operating Systems

One of the main reasons for the success of microcomputers has been the

dominance of a single operating system for the most common 8 and 16-bit

microprocessors. However, the advent of more powerful systons and the

introduction of numerous equivalent (but not compatible) products aimed

at both software developers and end users may change this situation for

the worse. Examples include the large number of UNIX variants and the

recent introduction of mouse-based operating systems or application

environments. Some standardization efforts are under way (e.g. the UNIX

standards committee of /user/group), but additional work in this area is

necessary to prevent the proliferation of different systems.

110
References

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BGAN83 Mike Egan, "Users Wary of Complex New Systems", MIS Week, February

23, 1983, p. 1

EIA69 Electronic Industries Association Engineering Department, EIA

Standard RS-232C; Interface Between Data Terminal Equipment and

Data Communication Equipment Employing Serial Binary Data

Interchange, Electronic Industries Association, Washington, D.C,

1969

EISE83 Bruce T. Eisenhard, "Corvus Omninet and Its Position in an

Hierarchical Network", Digest of Papers; Compcon '83, IEEE Catalog

No. 83CH1856-4, March, 1983, p. 247

FERR82 David Ferris, "User Support on IBM PC Crucial", Software News . December, 1982, p. 1

FINK83 H.E. James Finke, "Where is the Independent Dealer Going?", ISO

World , February, 1983, p. 56

FOST83 Edward Foster, "Serial Printer Market Warms to Thermal Transfer

Technology", Mini-Micro Systems , June, 1983, p. 103

FOST83b Susan Foster, "Networking Micros, Sharing Resources", Computer

Decisions, April, 1983

GAD78 Ccxnptroller General of the United States, Accounting Principles and

Standards for Federal Agencies — Title 2; Accounting, U.S. General

Accounting Office, 1978

GAD80 Comptroller General of the United States, Forest SErvice's REgion 5

Should Consider Less Costly Ways to Meet Word and Data Processing

Needs , U.S. General Accounting Office Report CED 81-15, October,

1980

GAD82 Comptroller General of the United States, Strong Central Management

of Office Automation Will Boost Productivity, United States General

Accounting Office Report GAD/AFMD-82-54, September, 1982

GLAT81 Hal Glatzer, Introduction to Word Processing , Sybex Publishers,

1981, U.S.A.

GULD82 Gary Gulden, "A Framework for Decisions", Compute rwor Id Qhr

November, 1982, p. 35

112
- Referaices

HAXH83 Peter Hayhouse, "Integration May Hold the Key to Future Software

Sales", Digital Retailing. July, 1983, p. 86

HIRS83 Alan Hirsh, "New Spreadsheet Packages Do More Than Model", MiniMicro Systems, June, 1983, p. 205

H0RD82 Ellis Horowitz, "The Office Workstation of the 80's1m ££J2Sl Office

Automation Conference, Merican Federation of Information Processing

Societies, March, 1982, p. 129

H0US82 Velina Houston, "Centralization a Problem", MIS Week , October 20,

1982

HUGH82 Jim Hughes, "Data Communications Technology", Computer Design . December, 1982, p. 211

IBM81 IBM Corporation, Guide to Operations for the IM Personal Computer.

1981

IEEE83a Institute of Electrical and Electronic Engineers, IEEE Standard

8Q2t3f CSMA/CD Access Method and Physical Layer Specifications, New

York, 1983

IEEE83b Institute of Electrical and Electronic Engineers, IEEE Standard

802.4 , Token-Passing Bus Access Method and Physical Layer

Specifications, New York, 1983

INTE82 Intel Corporation, Database Processor iDBP 86/440 Syston Summary

Austin, TX, May, 1982

IS081 International Standards Organization, Open Systens Interconnection - Reference Model , ISO/TC 97/SC 16, October, 1981

JCHN83 R. Colin Johnson, "Magnetic Disk Drives Ranain Leading Mass-Storage

Technology", Electronic Engineering Times. May 16, 1983, p,. 79

JCHN83b R. Colin Johnson, "PCS In Corporations: Last Hurdle Cleared",

Electronic Engineering Times. May 9, 1983, p. 1

KETC82 James Ketchel, "Human Factors Issues in the Design and Use of

Visual Display Terminals", MI££ Office Automation Conference . American Federation of Information Processing Societies, March,

1982, p. 129

JCILL83 Peg Killmon, "Tiny Floppies Squeeze in the Bits", Mini-Micro

Systems , May, 1983, p. 231

LEMM83 Phil Lonmons and Barbara Robertson, "Improving the User Interface at

Digital x^esearch". Byte. July, 1983, p. 286

LYNN82 Mary E. Lynn, "LANS, OA Integration Gain Credence, but...". Software

News. February, 1983, p. 44

113
References

MARK81 R.J. Markowitz, "Software Impact on Microcomputer Architecture: A

Case Study", piggst of Papers; COMPCON Spring IEEE Conputer

Society 81-CH-1626, p. 40

MCCU82 Tcm McCusker, "DPers Differ on Impl orientation of Micro Policies",

Software News , Decenber, 1982, p. 4

MEYE82 N. Dean Meyer, "Staffing an Office Automation Group", Computer

Decisions , Decanber, 1982, p. 78

MILL83 Frederick W. Miller, "Packing the Disks with More Data",

Infosystems , July, 1983, p. 79

MORL82 Peter Merely, 'V^etting the Most for Your Money", Computer Decisions,

Novonber, 1982. p. 74

NBS80 National Bureau of Standards Institute for Computer Science and

Technology, Guidance on Requirements Analysis for Office Automation

Systems, , NBS Special Publication 500-72, December, 1980

NBS81 Joan E. Knoerdel, A Survey of Standardization Efforts of Coded

Character Sets for Text Processing, NBS Special Publication 500-81,

September, 1981

NBS82 R.E. Rosenthal, ed,. The Selection of Local Area Computing Networks,

NBS Special Publication 500-96, November, 1982

NBS83a "Programming of Microcomputers" NBS ICST Special Publication (to be

published)

NBS83b "Selecting Microcomputer Systetis", NBS ICST Special Publication, to

be published

NBS83C "Selecting Microcomputers for Managerial and Administrative Uses",

NBS ICST Special Publication, to be published

NBS83d National Bureau of Standards, Interface Between Data Terminal

Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) for

(Operation with Packet-Switched Data Communication Networks, Federal

Information Processing Standard Publication (FIPS PUB) 100, July,

1983

NBS83e National Bureau of Standards, Message Format for Computer-Based

Message Systems, Federal Information Processing Standard Publication

(FIPS PUB) 98, March, 1983

NBS83f National Bureau of Standards, "Current List of Documents", available

from the National Bureau of Standards Systen & Network Architecture

Division, B218/Technology Building, Washington, D.C. 20234, 1983

(continuously updated)

114
Rochelle O'Hara, '"The Big Cheese", Computerwor Id November, 1982,

p. 45

Chris Peters, "The Microsoft Mouse", Byte , July, 1983, p. 130

L. Press, Low Cost Word Processing , J. Wiley & Sons, 1983

D.R. Ronan, "Executives Who Love Their Personal Computers", Computer

Decisions , January, 1983, p. 13

Chris Rutkowski, "An Introduction to the Human i^lication Conputer

Interface Part I: Theory and Principles", Byte, October, 1982, p. 291

Harry Saal, "Local Area Networks", Byte , May, 1983, p. 96

Henry Simpson, "A Human Factors Style Guide for Program Design",

Byte, , i^ril, 1982, p. 108

Hellena Smejda, "Local Area Networks to Grow at 28.6 Percent/Year",

Small Systems World , Decanber, 1982, p. 13

Helen Smejda, "Nightmares Ahead for Corporate Personal Computer

Users", Small Systems World, January, 1983, p. 13

D.C. Smith, et. al, "Designing the STAR User Interface", Byte , April, 1982, p. 242

Software Arts, Inc., "DIF Technical Specification", DIF

Clearinghouse, Box 527, Cambridge, MA 02139

Small Systems Group, CP/M Software Directory , Santa Monica,

California, 1982

Robert St. John, "Proposed 'Policy' Meno is First Step to Control",

Small Systems World , Septonber, 1982, p. 26

Sandra L. Tegler, "Factors Impacting the Evolution of Office

Automation", Proceedings of the IEEE , May, 1983, p. 503

Christopher Titus, et. al., 8080/8085 Software Design (Book 1), H.W. Sams Publishing Co., 1978, p. 200

David Whieldon, "Make Way for Micros", Computer Decisions , June,

1982, p. 184

Bryan Wilkins, "VDT Study to Focus on Abortions", MIS Week , Novanber, 17, 1982

Amy Wohl and Kathleen Carey, "We're Not Sure How Many We Have",

Datamation , Deconber, 1982, p. 106

115
References

WOQD83 George Woodmansee, "Vision Interface Design", Byte , July, 1983, p.

166

YOUN82 Arthur Young & Co., The Iinpact of Low Cost Conputing Technologies on

the Department of Defense , Report prepared for DoD, February, 1982

116
Appendix A - Glossary

APPEMDIX A - GLOSSARY

The major objectives in formulating the definitions in this glossary were

conciseness and simplicity. Thus, less common uses of some terms are not

presented. More formal and authoritative definitions are available in the

following sources:

American National Standards Institute, American National Dictionary for

Information Processing Systems. X3/TR-1-82, American National Standards

Institute, New York, 1982, (FIPS PUB 11-2)

Institute of Electrical and Electronic Engineers, IEEE Standard Glossary

of Software Engineering Terminology. IEEE Std 729-1983, Institute of

Electrical and Electronic Engineers, New York, USA, 1983

abort - the termination of computer program execution prior to its completion.

absolute machine code - a type of machine language which must be placed in a given part of memory in order to be executed.

acceptance testing - testing conducted to determine whether a system

satisfies specific criteria and to enable the customer to determine whether to

accept the system.

acoustic coupler - a device to connect a computer or terminal to the handset

of a telephone for data transmission (see also modem)

address - the designation of a particular memory location where data

are stored or a port location where a device may be accessed

algorithm - a finite set of well-defined rules that gives a sequence of

operations for performing a given task.

alphanumeric character - a letter or number

applications software - software which performs a specific task such as word

processing, spread sheet analysis, etc. (compare with syston software)

ASCII - Anerican Standard Code for Information Interchange. A standard for

the representation of 96 characters, digits, and printer control commands as a series of 7 bits. The ASCII code is the most commonly used standard for the

representation of characters in memory and for data communication.

117
J^pendix A - Glossary

assembler - a computer program used to translate a program expressed in an

assembly language (see below) into a machine language. This process is

usually accomplished by substituting machine codes for assembly language

mnemonics (see assembly language, below) and by replacing various forms of

syntolic addresses with specific memory addresses.

asseitbly language - a machine-specific language whose instructions are usually

in one-to-one correspondence v/ith computer instructions.

asynchronous serial communication ~ the communication of individual characters

over a communication channel as a series of bits. At the beginning of each

character, a "start" bit is sent to indicate a new character.

background processing - the execution of lower priority computer programs

when higher priority programs are not using system resources such as the

CPU. Example: a user is editing a document while printing another in

background.

back iie - a duplicate of a hardware systen, of software, or of data intended

as a replacement in the event of a malfunction.

batch processing or batch mode - the execution of a program or set of programs

on the basis of a single initiating action (compare with interactive

processing)

baud - A measure of transmission speed originally applied to teletype

terminals using the baudot code. Although not strictly the same, baud and

and bits per second are equivalent when used for digital communication with

the ASCII code (see ASCII, bits per second).

benchmark - the measurement of performance against a uniform set of standards.

bit - contraction of "M.nary digit". The smallest unit of information. A bit

can represent two values such as off/on, yes/no, true/false, or 0/1 (see also

byte)

.

bits per second - a measure of data transmission speed: number of bits

transmitted through a data channel in one second.

bootstrap - a short computer program that is placed in ROM and whose

execution brings an operating system (or other large program) into computer

memory.

£ES - see bits per second,

buffer - an area of RAM that is used to temporarily store data from a disk,

conmunication port, program, peripheral device.

bug - an error, mistake, or malfunction in a computer program (see debugging)

byte - usually a group of eight bits. Bytes are the most convenient units for

storing letters or characters (because of the ASCII code), computer

instructions, and syston status indications.

118
i^pendix A - Glossary

cathode tube display - A televisioii-like display that is commonly used

with a keyboard for displaying user input and computer responses. Also

referred to as "video display tube" or VDT.

cell - a location on a spreadsheet where either data or a formula is stored.

central processing unit - The "heart" of the computer which executes

instructions and computer programs.

code - (1) the representation of data or a computer program in memory such

that it can be executed by the central processing unit; (2) the process of

writing software; (3) one or more computer programs or part of a computer

program; (4) encryption of data for security purposes.

command oriented software - software which responds to a command string

entered by the user (generally through a keyboard). Compare with menu

oriented software.

coirpiler - A computer program which translates a high order language program

into machine language which can be executed by the central processing unit.

component - a basic part of a systen or computer program.

computer program - a sequence of instructions executed by the central

processing unit.

concurrent processes - processes (i.e. computer programs) that are executed

simultaneously.

conversion - modification of existing software to enable it to operate in a different language, on a different syston, or both

CPU - see central processing unit

CRT - see cathode ray tube display

cursor-location marker on a computer display screen, usually an

underline or rectangle.

custom software - software specially developed for an individual application.

data base - informal: information stored in a computer. More formal: a

(1) a set of data, part or the whole of another set of data, and consisting of

at least one file that is sufficient for a given data processing systen; (2) a collection of data fundamental to a system; (3) a collection of data

fundamental to an enterprise.

debuaaina - correcting mistakes in a computer program (see bug)

default condition or setting - a condition or setting that exists until

changed by the operator. An example of a default condition is a standard 66-

line page.

119
i^pendix A - Glossary

digitizing tablet - a device which indicates the relative position of a stylus

(or similar device) on a surface to the CPU.

disk - a circular, flat object made of plastic or aluminum and coated with

magnetic material used for storing information.

disk cartridge - a disk and the surrounding packaging material also referred

to as a disk pack. Generally used in relation to removable hard disks.

disk drive - the mechanical device and electronics which read and write data

from the disk into the CPU and memory.

diskette ~ a small disk. Generally used when referring to floppy disks of 8

inch size or smaller.

documentation - Technical data, including computer listings and printouts in

human-readable form which (1) document the design or details of the software,

(2) explain the capabilities of the software, or (3) provide operating

instructions for using the software to obtain the desired results from

canputer equipment. It also includes program listings or technical manuals

describing the operation and use of programs,

editor - a computer program that permits selective revision of computer stored

data,

efficiency - the extent to which software performs its intended functions with

a minimum consumption of resources.

execution - the process of carrying out an instruction or the instructions

of a canputer program by a computer.

field - a place in a record or file for storing an individual item of data

such as a name, account number, etc.

file - a collection of records or data which is stored, used, or generated by

a computer program.

filter - a program which takes the output from one program, performs an

operation on it, and passes it along to a second program. The term originated

in the UNIX operating system (see also pipe)

.

firmware - computer programs and data loaded in a class of memory that cannot

be easily modified by the user during processing.

floppy disk - a disk made of irylar or a similar flexible plastic material and

coated with magnetic particles and packaged in a paper jacket. Common

diameters are 5.25 and 8 inches. Also referred to as flexible disks.

font - typeface style (e.g. Italic, Courier, Letter Gothic, etc.)

footprint - the area of a desk, table, or other flat surface taken up by the

microconputer and associated equipment.

120
i^3pendix A - Glossary

foreground - the primary task being executed in a computer where several tasks

are being run simultaneously. Example: a user performing a text editing task

in foreground while another document is being printed in background.

hard copy - computer output printed on paper (as opposed to a disk or a CRT)

.

hard disk - a disk of aluminum or other rigid material which generally has

greater storage capacity and allows for higher access speed than a floppy

disk. Also referred to as a rigid disk.

hardware - the electronic and mechanical devices that comprise a computer

system.

help facility - software which controls the display of instructions on the

CRT screen when the user requests information while running a program.

high level language - see high order language

high order language - A computer programming language that does not reflect

the structure of any one given computer and that can be used to write machine

independent programs. A single high order language statement may represent

many machine operations.

iirplementation - (1) a realization of an abstraction (e.g. a system design) in

more concrete terms (e.g. the actual system); (2) the process of translating a design into a working computer program.

information utility - see value added network

instruction set - the set of instructions which a central processing unit

performs.

input - data entered into a system program by an operator, from a file, or from another device (e.g. a piece of laboratory equipment).

install - (1) the act of bringing a computer to the location where it is to be

used and performing tests to ensure that it is operational; (2) the act of

adjusting parameters on a purchased computer program so that it is compatible

with the particular hardware and peripherals on an individual systan.

installation - a way of referring to the computer system (e.g. "...this

microcomputer installation performs the following functions:..."); also can be

used as noun form of definitions (1) and (2) of install (above)

.

integration - ensuring that all components (both hardware and software) of a particular system work together and making the appropriate changes v^hen they

do not.

interactive processing - a type of program execution in which the user is

involved in the data input and control. Its purposes include the provision of

immediate feedback to the user, the exchange of information between the

computer and the user, and the correction of data input errors.

121
Appendix A - Glossary

interface - (1) a shared boundary; (2) a hardware component which links two

or more devices; (3) that function of a computer program which presents

information to an operator and accepts user responses.

interpreter - a canputer program which translates and executes each statement

of a compater language written in a high order language (e.g. BASIC or Pascal)

before proceeding to the next,

joystick - a stick-like pointing device (typically 1" to 3") which can be used

to indicate the speed and direction of cursor movement to the CPU.

justification - the alignment of letters on a margin (e.g. this glossary is

right-justified)

.

light pen - a pointing device which uses light from the CRT to indicate

position to the CPU.

maintenance - see software maintenance

machine language - a representation of instructions and data that is directly

executable by the central processing unit.

macroassent)ler - an advanced type of assembler that allows the user to define

a sequence of instructions that are inserted into a program during assannbly.

menu - a screen display which lists tasks the ccmputer can perform so that the

user can select the desired operation.

menu-oriented software - software which responds to the designation of a choice frcxn a menu (see above) rather than an explicitly typed in command.

merge - the combining of information from two sources (generally two data

files) into a third.

microcomputer - a computer system consisting of a central processing unit,

random access memory, and interfaces to pass data to and from peripherals

(such as disk drives) which is based on a microprocessor.

microprocessor - a central processing unit in a single integrated circuit.

modem - acronym for jnodulator /demodulator. During data transmission, the

modem converts the canputer representation of data (generally a voltage level)

into an audio signal for transmission of telephone, teletype, or intercom

lines. When receiving data, the modem converts the audio signal to the

computer data representation.

module - a well defined section of a computer program with a specific function

such as accounts receivable.

mouse - a small handheld pointing device which, when moved on a flat surface,

causes a corresponding movement of a cursor on a CRT

122
Glossary

multiprogramming - see multitasking

mu ltiprocessor - a computer which consists of several processors which may

execute programs simultaneously.

multitasking - the concurrent execution of several programs.

object program ox module - a fully compiled or assembled program that can be

loaded into a canputer memory and executed.

off line storage - storage of data on media which are physically removed fron

the system (e.g. a magnetic tape or a floppy disk) and stored elsewhere.

operating system - a computer program that controls the operation of the

computer including the execution of other computer programs, the routing of

data, and the control of peripherals.

output - information that comes from the computer as a result of its

processing.

overlay - the technique of running a r^rogram which is too large for the

computer memory by keeping inactive parts on disk.

parity bit - a bit indicating whether the sum of a previous series of bits

(generally a single character in asynchronous serial communication) is even or odd.

parity checking - the comparison of the sum of a previous set of bits with the

parity bit to determine if an error in the transmission or receiving of the

message has occurred.

password - a code word required to use a computer system or gain access to

program or data files.

patch - a modification of a program written in machine language that may be

used to replace another part of a program (which is generally an error)

without going through reassembly or reccHtipilation.

pe ripheral - a device such as a CRT, printer, or disk drive which is not an

integral part of the CPU and memory or devices which provides the CPU with

outside coirmunication.

pipe - the means by which data are passed through a succession of tasks (some

of which may be filters) . The term originated in the UNIX operating system

(see also filter).

pointing device - a device which u&ed to communicate cursor position

information to the CPU.

portability - a quality which describes the ease with which software can be

transferred from one computer system to another.

123
Appendix A - Glossary

print spooling - the ability to print the contents of a file in background

while another task is being executed in foreground.

prompt - a message informing a user that a system is ready for the next

ccMTiand, message, or other user action,

protocol - a set of rules that govern the way in which computers or other

functional units transfer data.

RAM - acronym for randan access memory (see below)

random access - the ability to access a particular data item without having to

read through all previous items.

random access files - files which are structured to allow access to any

particular record without having to search through all previous records in a

file.

random access memory - a memory that can be read or altered directly by the

CPU. The most common types of random access menory retain their contents as long as the system has power, but lose them whenever the power is turned off.

read-only memory - a memory that can be read by the CPU but can not be

altered. Generally this memory retains its contents in the absence of

electrical power.

read-write memory - see random access memory

real time computing - the performance of a conputation during the time that a

related physical process happens so that results of the computation can be

used to guide the physical process.

record - a collection of related data treated as a unit.

requirement - (1) a condition or capability needed by a user to solve a

problem or achieve an objective, (2) a condition or capability that must be

met or possessed by a system in order to satisfy a contract, standard,

specification, or other formally imposed document. The set of all

requirements forms the basis for subsequent development of the system (see

also specification).

sequential access - the ability to access data in a sequential manner, i.e.

the order in which it is stored. The best example of sequential access is a

file stored on magnetic tape. However, files stored on disks may also be

sequential.

software - computer programs, procedures, rules, and possibly associated

documentation and data pertaining to the operation of a computer system.

software maintenance - modification of a software product after delivery to

correct faults, improve performance or other attributes, or to adapt the

product to a different system.

124
Appendix A - Glossary

sort - the ordering of data (most commonly records) in a specific order, e.g.

alphabetically, in ascending numerical order, etc,

source code - the form of software used by programmers to create and modify

software.

specification - (1) a document that prescribes in a complete, precise,

verifiable manner, the requirements, design, behavior or other characteristics

of a system or component, (2) the process of developing a specification, (3) a concise statement of system requirements to be satisfied by a product or system indicating, whenever appropriate, the procedure by means of which it

may be determined whether the requirements given are satisfied.

support - the provision of advice and expert assistance in the operation of

the computer system and application software.

system - a collection of people, machines, and methods organized to accon^Jlish a specific set of functions.

system software - the operating systan and accompanying utility programs that

enable a user to control, configure, and maintain the computer system,

software, and data.

utilities - computer programs or routines which perform general data and

system related functions required by other application software, the operating

syston, or users. validation - the process of evaluating software to ensure compliance with

software requirements and correctness.

value added network - a network of computers owned or controlled by a single

entity which can be used for data transmission, electronic mail, information

retrieval, and other functions by subscribers.

virtual memory - a technique by which the central processing unit can use more

memory than is available in RAR The operating syston writes the contents of

inactive memory to a disk drive when that portion of memory is needed for

another purpose and retrieves the contents from the disk as appropriate.

Winchester disk - a type of rigid disk in a sealed unit.

125
Appendix B - Annotated Bibliography

APPENDIX B - ANNOTATED BIBLIOGRAPHY

This appendix lists some of the useful books and articles which were

encountered in the course of preparing this report. This list emphasizes

works which can be read with little or no previous computing background, and

are organized according to the follwing topics:

General Overviews

Microcomputer Market

Word Processing and Auxiliary Programs

Administrative i^lications

Communications

Organizational Issues

GEiSIERAL OVEE?VIEWS

Laurence Press, "Getting Started in Personal Conpjting", onCoirputing, Spring,

1981, p. 8

Describes microcomputers with an emphasis on the basic hardware

components. The article can be easily read by those without prior

knowledge of computing.

Carol Brown, The Minicoitpiter Simplified , The Free Press, New York, 1980

A book oriented to non-technical managers in organizations considering

the introduction of minicomputers. The volume is well written, and most

of the material on computer hardware and software development is relevant

to microcomputers as well.

D. Whieldon, "Make Way for Microcomputers", Computer Decisions, June, 1982, p. 158

Describes microcomputers from managerial point of view and does not

require any computing background for understanding. Gives examples of

applications and describes motivations for use. The article also

includes a discussion of organizational issues including management,

configuration control, and relations with the data processing department.

H.D. Toong and Amar Gupta, "Personal Computers", Scientific American, December, 1982, p. 86

A more serious and thorough overview intended for a scientifically

sophisticated audience but not one which is expert in computing.

Describes hardware, the functioral organization of microcomputers, some

of their history, market trends, and applications.

126
i^3pendix B - Annotated Bibliography

Otto Friedrich, et al., "The Computer Moves In", Time Magazine . January 3,

1983, p. 14

An easily read series of articles which describe the Time Magazine "Man

(Machine) of the Year". Although not technically informative and overly

sensational in some areas, the articles can provide readers with a feeling of the microcomputer industry personalities, major companies, and

some future market trends.

MICROCOMPUTER MARKET

International Data Corp., "Computer Systems and Services", Fortune. May 16,

1983, p. 24

A marketing oriented overview of the microccxnputer industry which is a digest of the results of past IDl studies. Although covering all aspects

of the computer industry, the bulk of the report covers microccmputing

and related topics.

Staff, "Special Report: Look Ahead 1983", Business Conputer Systems. January,

1983

A digest of projections and expert opinions and projections on the

microcanputer industry. Somewhat sensationalized, but some interesting

ideas, e.g. "the office of the future is as far off as it was five

years ago"; "by 1990, every manager will have computing power through

desk top systems"; and "computing power is a commodity.. like

electricity"

WORD PROCESSING AND AUXILIARY PROGRAMS

Laurence Press, Low Cost Word Processing , Addison Wesley, 1983

This book describes word processing on microcomputers and is oriented to

readers with no prior experience. As part of the discussion, the book

also describes microcomputer hardware, software, and integration of word

processing with other applications. A list of selection criteria, sample

hardware configurations, and vendors is also included.

Terry Kepner, "Spelling Checkers for the TRS-80", Popular Computing January,

1983.

This article compares four spelling checkers for the TRS-80 and in doing

so presents a checklist of 20 program attributes. A discussion of the

pros and cons of each program is also provided.

Robert Perry, "Mailing List Packages — a Mainstay for Business", Personal

CcHipiting . January, 1982.

This is a canprehensive article covering mailing list packages. Several

sample applications are outlined and package features are discussed.

127
Appendix B - Annotated Bibliography

Record definition, sorting, file size, retrieval, report generation, and

mailmerge are covered. Eighteen packages are reviewed briefly, each has

a one-paragra0i description and a checklist of features and capacities is

presented.

Karen Shelby, "Information Processing in a Legal Environment", Proc.

Synoptican X, Kansas City, MO, June 24, 1982

Defines the functional requirements of computing in a private legal

firm.The most important need is multiuser word processing (i.e. the

ability of several typists to work on the same document). Other needs

include timekeeping, schedules, and docket control.

ADMINISTE^TIVE APPLICATIONS

Andrew Fluegelman, "Visi-Calc versus SuperCalc, a Head to Head Comparison",

£C Magazine, August, 1982.

This article compares the two programs and in doing so establishes a framework for conparison with other interactive spreadsheet processors.

Some basic terms are defined and several general areas are covered,

including, interaction and data entry style, arithmetic precision,

formatting options and flexibility, display data types, replication,

cursor movement, block operations, windowing and protection, functions

and operators, speed of calculation and file transfer, output options and

documentation. An informal description of a pre-release version of

Multi-Plan appears in the same issue of the magazine.

Myron Berger, "Scenarios for Success: The Vision of Spreadsheeting",

Personal Computing, i^ril, 1982.

This is a short article written for the beginner. It briefly describes

what a spreadsheet program is and then gives a number of examples, based

on mini-interviews with users. The applications stress the ease of "what

if" analysis and cover areas such as proposal and bid preparation,

business plans, alternate budget scenarios, and aggregation of

departmental budget reports. Resources such as newsletters, users

groups, prewritten applications and books are also mentioned briefly.

Robert R. Mueller, "Business Planning Software", Personal Computing , November, 1982.

This article discusses non-planning applications of planning software,

makes the distinction between screen-oriented and program-oriented

programs, and covers the use of models. The author feels that the

program-oriented languages are easier for clerical people to run once the

model has been constructed by a professional. The necessity of

understanding the assumptions programmed into any model you use and the

risk of not doing so when using commercially available tonplates (preprogrammed models) is onphasized. A list of several software suppliers

is included.

128
Appendix B - Annotated Bibliography

Carl Heintz, "Evaluation of Financial Planning Packages", Interface Age, July,

1982.

This article sets out a framework for the comparison of financial

planning packages. Some earlier timeshared packages are mentioned for

historical perspective and the distinction between screen- and programoriented languages is drawn. The author feels that in general, screenoriented languages are less powerful, but siirpler for non-programmers to

learn to use, since they are less abstract. The bulk of the article is

taken up with brief comments on each of 28 attributes which may be used

in comparing programs. A checklist acccmpanies the article, scoring 32

programs on the 28 attributes.

Jack Bishop, "Beyond the Peaks of Visicalc", Byte, October, 1982, p. 29

This article compares three spread sheet processors with VISICALC and

includes some insights on spread sheet operation and user criteria in

addition to a discussion of the merits of the three packages.

M. Lasden, "Computer Aided Decision Making", Computer Decisions , November,

1982, p. 158

Defines the requirements for a computer-based "decision support system"

which includes data query and retrieval, spread sheet analysis, and

graphics. Points to need for mainframe based decision support systems on

the basis that some applications are too big for a microconputer in large

organizations.

COMMUNICATICNS

Michael Killen, "The Microcomputer Connection to Local Networks", Data

Communications, December, 1982.

This article summarizes an extensive report prepared by Strategic Inc.

It surveys the low-speed local network market, as opposed to Ethernet or broadband networks. There are about 12,000 low speed networks installed

as compared to 800 high speed networks. A typical configuration is four

personal computers with floppy disk, and a shared hard disk and printer.

Typical data rate is 3 million bps. The cost of a typical network

interface is $500 today and is expected to drop to about $50 by 1987

(compared to $2,000 and $500 for Ethernet). The author states several

advantages of LANs over timesharing and gives brief descriptions of 16

products. Four installation case studies are also summarized briefly.

The lack of standards is noted; however, Corvus and Datapoint are

encouraging other vendors to use their networks.

Wallace B. Riley, "Local Area Networks Move Beyond the Planning Stage",

Systems and Software, Novenber, 1982.

This article surveys LAN technology choices. Baseband and broadband are

both covered in roughly the same depth. Pros and cons of the two

approaches are mentioned. Issues and terms encountered in PC networks

129
Appendix B - Annotated Bibliography

(virtually all baseband today) such as randan versus controlled access,

collision detection and token passing strategies are summarized.

G. FitzGerald and T.S. Eason, Fundamentals of Data Communication . Wiley, 1978

This book provides a fundamental description of data communication.

Because it is intended as a textbook in managonent schools, the book is

rigorous but does not require a technical background. However, some

background knowledge of computing is necessary. Although not aimed at

microcomputers, the technical concepts it discusses in the areas of both

synchronous and asynchronous ccmnunication are relevant.

Tony Bove, "What is Teledon, and Why is AT&T Adopting It?", Datacast , No. 1.

Teledon is a presentation level protocol for the communication of text

and simple pictures between computers. The notation for describing

pictures consists of a "command" specifying text, point, line, arc,

rectangle, polygon, bit-mode or control-message, followed by coordinates

(9-bit accuracy) and operands. The notation is not fully specified in

this article, but a discussion of standardization in the general

"videotext" area is presented as are descriptions of 12 Teledon-based

projects in the US and Canada. Teledon interpreters have been

impl oriented on several personal computers.

Errol Smith, "Videotex", CP/M Review. January/February, 1983.

AT&T has proposed a new standard for picture and data transmission. It

is ncM being studied by ANSI. The protocol includes provision for text,

m.osaic graphics, lines and shapes, a redefinable character set, and some

control operations. This article summarizes the protocol.

GRAPHICS

Elisabeth Bayle, "Picture This and Do it Yourself", Personal Computing , August, 1982.

An introductory overview of business graphics applications and software.

Thumbnail sketches of several industrial applications are given. Short

reviews of several programs for the Apple, IBM and CP/M-based computers

are given. Presentation systems, including one which is capable of

limited animation and mixing of video and digital display are discussed

in addition to static graph-design systems. A list of vendors is

provided.

David Gabel, "Computer Graphics: The Perfect Visual Message", Personal

Computing. February, 1983.

This article gives an overview of business presentation graphics (bar

charts, pie charts, plots) on personal computers. It surveys input

devices (keyboard, light pen, trackball, mouse, digitizer) and output

devices (display, plotter, printer). Software is discussed in general

terms. An example using PFS Gra0i is shown and some sample applications

130
i^ipendix B - Annotated Bibliography

are mentioned. An index of hardware and software vendors accompanies the

article.

URGANIZATIONAL ISSUES

Amy Wohl and Kathleen Carey, "We're Not Sure How Many We Have", Datamation , December, 1982, p. 106

Discussion of the results of a survey of corporate microcomputers which

identifies significant problems in the areas of configuration control,

coiimunication, software, hardware maintenance, and support.

Robert A, Becker, "The Need for Rigorous Analysis of OA Proposals", Conputer

Decisions. November, 1982, p. 78

Discusses problems in implementing office automation systems among

users who are reluctant to use any kind of automated data processing

equipment and those who are overly enthusiastic about the hardware. Also

identifies difficulty of cost justifying installation of office

automation systems.

B.G.F. Cohen, M.J. Smith, and L.W. Stammerjohn, "Psychosocial factors

Contributing to Job Stress of Clerical VDT Operators", AFIPS Office Automation

Conference , American Federation of Information Processing Societies, March,

1982, p. 117

Describes the results of a NIOSH study of VDT (i.e. CRT) workers in large

organizations. Although the study was apparently (not explicitly stated)

for mainframe systens, the results have implications for microcanputer

based systens as well. Among the conclusions are that job stress from

other factors can be exacerbated by the introduction of computing

technology and that clerical workers experienced more stress than

managerial workers because the latter had discretion over the use of

their systems.

Ccmptroller General of the United States, Strong Central Manaqarient of Office

AutCTnation Will Boost Productivity, United States C^neral Accounting Office

Report GAD/AFMD-82-54, September, 1982

A study of five office automation installations in Government agency and

one corporation. The study pointed out a number of problsn areas and

cited problems in establishing cost justification and following the

progress of the syston after installation. The study has implications

for major purchases of microcanputers by Federal agencies as well as the

installation of microcomputer-based local area networks as well

131

NBS-n4A iREv. 2-8C) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

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1. PUBLICATION OR

REPORT NO. NBS SP 500-110

2. Performing Organ. Report No. 3. Publication Date

March 1984

4. TITLE AND SUBTITLE

Microcomputers: Introduction to Features and Uses

5. AUTHOR(S)

Myron Hecht, Herbert Hecht, Laurence Press

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National Bureau of Standards

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11. ABSTRACT (A 200-word or less factual summary of most si gnificant information. If document includes a significant

bibliography or literature survey, mention it here) This document is an introduction to microcomputers and their uses in the Federal

government. Basic concepts in microcomputers are discussed, and their uses by

clerical, administrative, professional, and technical Federal personnel are described. The motivations, costs, and risks of microcomputer use are identified,

and recommendations for successful implementations are provided. Appendices

contain a glossary and annotated bibliography.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

microcomputer hardware; microcomputer management issues; microcomputer software;

microcomputer technical considerations; microcomputers.

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