l^Ssist NEWSLETTER vol.1, no. 4

DISCUSSION PAPER/ michel melton

An Overview of Display Terminals

Michael Melton
Battelle Columbus Laboratories

Columbus, Ohio

Overview

Display terminals can be generally classified into three categories: (1)

dumb, (2) semi-stupid, and (3) intelligent.

Dumb terminals offer a limited number of functions and most closely resemble

Teletypes. Semi-stupid terminals usually offer a certain amount of features,

most likely, data input editing and formatting. Some terminals in this class can

be tailored to fit a specific application via a limited programming capability.

Intelligent terminals are supported by software programs. The vendors typically

provide an operating system, an assembler or a compiler, I/O utilities, and one

or more application programs such as text editing or data entry. Programmable

terminals provide the user with the highest degree of flexibility, permitting

the terminal to be tailored to the user's environment. Some programmable termin-

als are available as turnkey terminals, which means that the program is furnished

by the vendor and the terminal is ready to use as soon as it is installed.

Cost is usually proportional to capability. Dumb display terminals are the

least expensive at $1000 to $2000. Intelligent terminals range upward from $6000.

Expensive items include increased memory, additional display units, and peripher-

als such as diskette or disk storage and printers. Semi-stupid terminals are

priced somewhere inbetween.

Some brand names in dumb terminals include Applied Digital Data Systems,

Beehive, Infoton, and Lear Siegler. Some of the semi-stupid terminals include

Hewlett-Packard 2640, IBM 3270, ICC 40+, and the Univac Uniscope. Some intelli-

gent terminals are Applied Digital Data Systems 70, the Beehive B800, Datapoint,

Four-Phase Systems Incoterm, Sycor, and Univac UTS400.

Most terminals introduced on the market in the last three years have been

microprocessed-controlled (i.e., intelligent). Microprocessors are cheap, cut

design, development, and production costs, and they lend themselves to a variety
of applications that can be implemented by the vendor or the user. Computer
programs which control the functions of an intelligent terminal are called firm-

ware. The user can control the terminal's functions by either changing a set of

parameters or by adding new firmware to the microprocessor.

Display Functions

Some different terminal display functions are:

(1) Color - Few display terminals offer color but some offer up to eight colors

(2) Reverse video - A negative image of the data, data normally displayed in

white or dark background is displayed in black or white background

(3) Programmable brightness level

(4) Character or field blinking

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sist NEWSLETTER vol.1, no. 4

(5) Roll or scroll data is rolled up or down the screen, permits the user to scan

a large volume of data

(6) Paging - Data is stored on pages (a full screen) user is able to review any

selected page.

Editing Functions

Editing features include:

(1) Character deletion

(2) Line insertion

(3) Line deletion

(4) Erase

(5) Character repeat.

External I/O devices can add flexibility to the applications possibilities
for display terminals. A cassette tape drive or diskette drive can be used to

store display formats, data to be transmitted, or user programs. A printer can

provide hard copy.

Selecting a Terminal

Some questions you should ask yourself when selecting a display terminal are:

(1) What are the essential parameters for a display terminal that will satisfy

your needs?

(2) Who supplies the terminals with the features you desire?

(3) Maintenance provisions?

(4) Talk to users concerning problems encountered when installing it, failures

that have occurred, and any incompatibilities.

DISCUSSION PAPER/alice robbin

The Issue of Confidential Data: The Need for

Formulation of Policy by the Data Archive and Library

by

Alice Robbin
Data and Program Library Service
University of Wisconsin-Madison

The Issue of Confidential Data

I.

During the last decade there has been increased concern about the problems
of confidentiality involved in the collection and dissemination of individual
microdata. Concern has revolved around the government's perceived need to col-

lect increasing amounts of information at a microdata level for social policy
formulation and evaluation, types of information which potentially compromise