Decuscope_Vol07_1968 Decuscope Vol07 1968

Decuscope_Vol07_1968 Decuscope_Vol07_1968

User Manual: Decuscope_Vol07_1968

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HAVE YOU SENT IN YOUR ABSTRACT
FOR THE
DECUS SPRING SYMPOSIUM
IN PHILADELPHIA?
IF NOT, THERE MAY STILL BE TIME, LOOK THRU THE PILE OF PAPERS ON YOUR DESK FOR THE GREEN
FLYER TITLED - uCALL FOR PAPERS u; COMPLETE THE SECTION CALLING FOR AN ABSTRACT AND MAIL IT
TODAY TO THE DECUS OFFICE, IF YOU HAVE SYSTEMS PROGRAMMING TO TALK ABOUT, COMPLETE THE
SHEET REFERRING TO WORKSHOP PARTICIPATION,
IN CASE YOU HAVEN'T HEARD, THE SPRING SYMPOSIUM WILL BE HELD AT THE BELLEVUE STRATFORD HOTEL
IN PHILADELPHIA ON APRIL 26TH AND 27TH, SESSIONS HILL BE HELD ON THE FOLLOWING APPLICATION
AREAS: BIOMEDICINE, TYPESETTING, EDUCATION, AND HIGH ENERGY PHYSICS,
THE FOLLOWING WILL SERVE AS CHAIRMEN FOR THEIR RESPECTIVE SESSIONS:
GENERAL MEETINGS CHAIRMAN
WORKSHOP CHAIRMEN
PROFESSOR PHILIP R, BEVINGTON
ROGER PYLE
PDP-8 LINE:
DIGITAL EQUIPMENT CORP,
PHYSICS DEPARTMENT
MAYNARD, MASSACHUSETTS
STANFORD UNIVERSITY
STANFORD, CALIFORNIA
BIOMEDICAL SESSION
PDP-9:
JAMES MURPHY
DIGITAL EQUIPMENT CORP,
PROFESSOR BELMONT FARLEY
MAYNARD, MASSACHUSETTS
JOHNSON FOUNDATION
UNIVERSITY OF PENNSYLVANIA
PHILADELPHIA, PENNSYLVANIA
PDP-IO:
DAVID FRIESEN
MASSACHUSETTS INSTITUTE OF
EDUCATION SESSION
TECHNOLOGY
CAMBRIDGE, MASSACHUSETTS
DR, SYLVIA CHARP
DIRECTOR OF INSTRUCTIONAL SYSTEMS
BOARD OF EDUCATION
MODULES:
SYPKO ANDREAE
PHILADELPHIA, PENNSYLVANIA
LAWRENCE RADIATION LABORATORY
BERKELEY, CALIFORNIA
TYPESETTING SESSION
RICHARD MCQUILLIN
INFORONICS INC,
CA~BRIDGE, MASSACHUSETTS
CDt.CUS PRESIDENT)
HIGH ENERGY PHYSICS SESSION
PROFESSOR THOMAS DAY
PHYSICS DEPARTMENT
UNIVERSITY OF MARYLAND
COLLEGE PARK, MARYLAND

PRESIDENT'S LETTER

CONTENTS

As new President of DECUS, I wou:d like to report tothe membership about some new developments in the Society.

PAGE

President's Letter.
Editorial

The newly installed Executive Board has vacant positions. My
election to the presidency created a vacancy in the office of
Programming Chairman. To this office I have appointed a
present board member, Mike Wolfberg, the previous Publ ications Chairman. In addition to this, newly elected Nancy
Lambert has been unable to take office as Recording Secretary
due to a new job unrelated to DEC hardware; so anyone interested and able to contribute actively to DECUS administrative affairs by serving on the Board may contact me for further details.

.....

DECUS Annual Report - 1967 . .

3,4

DECUS Canadian Symposium

4-6

7-10

Programming Notes . . . . • •
Text Facility for Use with PDP-8

7,8

Multiplexing of Data Address Bits for PDP-8
3-Cycle Data Break Facility . . . . .

8,9

Punching Binary Tapes on the LI NC-8 .

With the rapid growth of the Society, it is becoming apparent
that some changes may be in order in Executive Board structure.
We need more help in keeping the high momentum that we have
had for the past few years. I feel that these are two mainareas
of immediate need: Programming and Meetings. I have asked
Mike Wolfberg to structure the Programming Committee along
product I ines. This has been started with Mike reviewing PDP-8
software as it comes into the DECUS Library. Dave Friesen of
M.I.T. is doing the same forPDP-6/10 software, and Mike is
look i ng for someone to rev iew PD P-7/9 softwa re .

Wanted

Letters

10, 11

Modu Ie News. .

11-13

New DECUS Members

14-16

Digital Software News

17-24

PDP-5, 8, 8/S . .

17-20

PDP-7/9 . . . . •

20-24

The last couple of technical meetings have been tremendous
undertakings for our previous Meetings Chairman, Don Molony.
The meetings have had about two hundred attendees, and this
number cou Id easi Iy double in the next few meetings. Therefore, I have asked Phil Bevington to look for people to work
on the Meetings Committee, especially to help with the East
Coast meetings. Anyone interested in working on this Committee should contact Phil at Stanford.
Also on the subject of meetings, we have received good reports about our last meeting in Anaheim, in particu lar the
hand Iing of the workshops. Next time we intend to expand
on this plan and schedule workshops for each product line and
modu les. Anyone who wishes to present a paper pertinent to
anyone product line (e.g., a new assembler) will be given
a chance to do so at an appropriate workshop. The remainder
of the meeting will be for application-oriented papers in Education, High Energy Nuclear Physics, Biomedicine, and Typesetting. We are organizing these sessions well in advance this
time, along with session chairmen to set up and run these sessions. Hopefully, we will have a very useful meeting in
Philadelphia.

NOTE
The volume number of the last issue of DEC USC OPE was erroneouslyomitted. The issue (Season's Greetings on the cover)
should be numbered Vol. 6, No.6.

DECUS PROGRAM LIBRARY NOTE

As a final note, I wish to report on the new format of the Board
Meetings initiated in January. We are now having meetings
with everyone present by using a WATS line between DECUS
headquarters in Maynard and Stanford University. The first
meeting was very successfu I, and we hope to continue with the
system.

DUE TO THE LARGE BACKLOG OF REQUESTS FOR
PROGRAMS ANNOUNCED IN THE LAST ISSUE OF
DECUSCOPE, WE ARE NOT INCLUDING ANY ADDITIONS IN THIS ISSUE, WE ARE, HOWEVER,
PLANNING ON SENDING OUT AN ANNOUNCEMENT
OF NEW PROGRAMS AROUND THE MIDDLE OF
MARCH,
THIS WILL ENABLE US TO "CATCH
UP" ON REQUESTS BEFORE MORE COME "POURING IN", PLEASE BEAR WITH US UNTILTHEN,
THE

DECUS

We, on the Executive Board, are most happy to receive suggestions from the membership. Our purpose is to have a better
and more useful Society. We are growing rapidlyand wart to
keep our momentum through enlightened administration.

PROGRAM LIBRARY

Richard J. McQuillin
DECUS Preside'lt

EDITORIAL

DEC US ANNUAL REPORT - 1967
John B. Goodenough
President - 1966-1967

On the cover of this issue we have tried to illustrate the extraordinary growth of DECUS since its inception in 1961.
During the past year, we have more than doubled in growth
as well as service to the users.

The attached report of the DECUS Executive Secretary presents
a statistical summary of DECUS activities during 1967. The
purpose of the present report is to interpret these statistics and
assess the events that affected DECUSls operations during the
past year.

Below are listed the statistics showing DECUS activity for 1967
along with a comparison to i 966. Foi iowing these statistics
is a report by 1967 1 s DEC US President, John Goodenough,
which outlines what has been happening in DECUS during the
past year.

The single most important development in DECUS is the tremendous growth in membership--DECUS now has more than
twice as many members as it had at the end of 1966. This
growth has had important effects on our three primary activities: (1) the holding of technical symposia; (2) the distribution of computer programs; and (3) the distribution of information by means of DECUSCOPE, the DECUS newsletter.

DECUS Statistics for Year 1967
MEMBERSHIP

1967

1966

New Applications

1189

424

Total Membership
(Removed 31 in 1967)

2008

850

Delegates

925

385

Individuals

1049

465

Module Users (64)

Meetings
Our larger membership is reflected by the increasingly professionalqualityof thesemi-annual DECUSmeetings. TheSpring
and Fall DECUS Symposia were attended by 200 persons--the
largest attendance yet for a DECUS meeting; and at the Fall
meeting, over thirty technical papers were presented, more
than ever before. The increasing technical depth in DECUS
means that meetings can be organized with parallel sessions
devoted to relatively narrow technical areas. The Spring
Meeting in 1968 wi /I be the first to fu lIy take advantage of
DECUSls greater technical depth.

34 (not a Iready
members)

Non-Members

480

160

Tolal on mailing list

2488

1010

2775

1975

Number of programs subm i tted
(104 accepted, 23 in process)

127

Total number of programs in library

294

198

none

DECUSCOPE
Circulation

A larger membership is also evidenced by the interest in regional and special purpose meetings. During 1967, a special
one-day Biomedical Symposium wa s held in New York, a
meeting of Canadian members was held in Canada, a meeting
of European users was held in England, and a Module Users
Group was organized within DECUS.

PROGRAM LIBRARY

Number obsoleted
Number of request!; completed

950

Number of programs issued to requestors

4655

1692

Number of tapes involved in requests

8815

3460

Paper Tapes
DECtapes
Number of tapes reproduced (verified)

To meet the potential needs and problems posed by these and
future special interest groups, the DECUS Constitution was
amended in 1967 to provide for a special form of organization
within DECUS--the Special User Group (SUG). Each SUG
wi /I have its own Chairman and may organize its own meetings
or technical sessions with the aid and support of DEC US. The
DECUS European Committee is the first DECUS Special User
Group.

8690

Prol iferation of meetings imposes a severe burden on the DECUS
staff and detracts from the importance and qua Iity of the sem iannual general DECUS meetings. The DECUS Board has informally adapted the pol icy of discouraging meetings that are
separate from the Spring and Fall DEC US Symposia. Instead,
groups with special interests will be requested to organize
special sessions at one of our semi-annual meetings. We feel
that this pol icy wi /I increase the qua Iity and interest of the
DECUS meetings, decrease the burden on the DECUS staff,
and better serve the needs of all DECUS members.

124
9300 (approx.)

PERCENTAGE OF INCREASES
135% Increase in membership growth
146% Increase in number on mailing list
125% Increase in size of DECUSCOPE (minus insert section)
40% Increase in DECUSCOPE circulation (affected by revising mailing procedure)

Financial
DECUS derives income from the holding of its technical symposia. Our meetings are budgeted to cover expenses without
making a profit, but surplus from any meeting is added to the
treasury to cover any deficit that might occur in future meetings.
It was decided this year that the primary purpose of the DECUS

102% Increase in number of programs issued
175% Increase in number of programs issued
170% Increase in tape reproduction

DECUS CANADIAN SYMPOSIUM

treasury is to provide a hedge against unexpected costs at future meetings. In particular, it was decided that funds from
the treasury cou Id not be used to defray trave I expenses of any
electedmember of the DECUS Boardwhoistravelingon DECUS
business.

The second DECUS Canadian Symposium was he Id at the Skyl ine
Hotel in Ottawa on February 23. Below are abstracts of the.
papers presented. Proceedings of themeetingshould be avail-.
able in Apri I.

Since most of the DECUS operating expenses are covered by
the DECUS-DEC Support Agreement f DECUS has no need and
no intention of bui Iding up a large treasury.

SMALL COMPUTER APPLICATIONS IN A POWER SYSTEM

Program Li brary

J.D.A. Griffin
Ontario Hydro, Research Division
Toronto, Ontario, Canada

The increase in membership and the addition of new computers
to the DEC product line resu Ited in an explosive growth in the
number of programs distributed by DEC US. Approximate Iy
9,300 program tapes were duplicated (and verified), filling
approx imate Iy 950 requests for programs. The DEC US program
Iibrary is clearly in active use by the membership.

This paper concerns the use of a PDP-S to investigate possible
computer appl ications in certain areas of power system operation. Study thus far has centered primari lyon computer-based
re lay protection and on computer-controlled displays for control rooms. For the initial investigations, a method of generating CRT displays has been developed which, being both
effective and low-cost, may find application elsewhere.

The tremendous number of tapes distributed placed extreme
demands onthefacilities and procedures for duplicating tapes.
Present procedures allow for a two to three week delay in filling a request, but problems can be anticipated in 1965 when
present duplicating facilities become saturated.

AUTOMATIC PROCESSING OF ABSORPTION SPECTRA
DECUSCOPE

Roch Lafrance
Canadian Armament Research
and Development Establishment
Quebec, P. Q., Canada

The monthly DECUS newsletter has grown in size, primarily
because of the distribution of DEC Program Maintenance notices within DECUSCOPEand because of the inclusion of letters from members. Both kinds of information are felt to be a
significant addition, increasing the usefu Iness of DEC USC OPE
to members. Offsetting the increase in size, the DECUSCOPE
mailing list and mailing procedure was revised to insure that
copies were not distributed unnecessari Iy.

In the experiment to study the high-altitude atmospheric composition, a large number of absorption spectra are recorded
with a FM-FM telemetry system.
Automation of the data processing replaces the use of a planimeter by electronic integrations controlled in width and position by a program. From these integrals, the absorption of
a given spectrum band is computed, as well as other experimental parameters such as altitude and temperature.

DEC US-DEC Support Agreement
The activity in the program library and the large attendance
at technical symposia show that DECUS is meeting important
needs of itsmembers. Ourabilityto meet these needs ispredicated on the sU,)port DEC gives DECUS as described in the
DECUS-DEC Support Agreement. 1967 marked the first full
year of operation under this agreement, and the agreement
has proven usefu I and workable.

A computer, the PDP-S/S, and an interface consisting mainly
of five counters sum the signal frequencies given by the FMFM telemetry system with an accuracy of 0.1 cycle and allow
more than 500 integrations per second. The counter time base
is a reference frequency recorded on the magnetic tape. This
automatica Ily compensates for the wow and flutter of the playback recorder.

Commendation

Finally, the system controls a pen recorder to reproduce at high
speed the most interesting parts of the spectrum.

The DECUS Executive Secretary is provided under the Support
Agreement, and the DECUS Board is particu larly apprec iative
of the initiative and good judgment exercised by Mrs. Angela
Cossette in carrying out her responsibi Iities.

USE OF THE PDP-S/S FOR DATA ACQUISITION
AND CONTROL OF THE AERODIST
AIRBORNE SURVEY SYSTEM

FALL 1967 SYMPOSIUM PROCEEDINGS

Gordon R. Symonds
Department of Energy, Mines and Resources
Ottawa, Ontario, Canada

The proceedings of the Fall Symposium he I din Anaheim,
Cal ifornia on November 10 and 11 are now avai lable. Copies
are being mailed to all meeting attendees. ,h,nyone else interested in obtaining a copy should contact the DECUS office.

The Surveys and Mapping Branch of the Department of Energy,
Mines and Resources employs an integrated airborne survey
system which permits distance measurement, photo positioning
and extension of ground surveys over re lative Iy lorge distances
4

to Geodetic prec ISlon. The interface between the system-wh i ch inc ludes "Aerodist", a 3-channe I microwave distance
measuring un it, camera, radar profi Ie recorder and various
temperature and pressure measuring devices, and the PDP-8/s-is described. The processor is also used in the field office for
final data reduction by the computing section, giving the un it
high utility. Special operational problems encountered in
aircraft and field office use and their solutions are illustrated.

A PROGRAM TO SIMULATE NAND LOGIC SYSTEMS
I. A. Davidson
Northern Electric Company Research and Development
Ottawa, Ontario, Canada
A NAND logic system simu lator has been written for a
PDP-8/S. The network arrangement is described through the
Teletype keyboard, the input signals via the switch register
while the output levels are typed out. The simulator considers
the time taken for disturbances to be propagated through the
system unti I a stable configuration is found.

PDP-9T: COMPATIBLE TIME SHARING FOR THE
REAL-TIME LABORATORY

Various systems have been simulated, including the interface
logic for a card reader.

M. M. Taylor1, D. M. Forsyth 2 , and L. Seligman 3
Modifications have been made to the PDP-9 to permit realtime control of laboratory apparatus in a time-shared environment. The system is designed to accommodate about six
independent real-time users, providing each with device service latenc ies of under 100 microseconds and response latenc ies
of a few mi lIiseconds. At the same time, a simi lar number of
interaction or background jobs maybe sustained by this system
(e.g., editing assembling FORTRAN jobs). The PDP-9T system provides each user with a virtual memory space of 32K words.
Physical core of the PDP-9T may be expanded to 256K words.
The virtual user machine looks like an ordinary PDP-9 except
that (1) a few instructions trap to the monitor (e.g., HLT,
OAS); (2) an lOT instruction is decoded by hardware into 1
of 256 possible calis to the system monitor; and (3) programs
written to capitalize on the nature of the environment will
run more effic iently than those which pretend to be in an ordinary PDP-9. (This paper was given at the Fall 1967 DECUS
Symposium, Anaheim, California.)

SOME EXPERIENCES IN INTERFACE DESIGN
AND FABRICATION
E. J. Gabe and R. H. Goodman
Department of Mines, Energy and Resources
Ottawa, Ontario, Canada
An interfacehasbeenbuilt which will allow a 4-Circle X-Ray
diffractometer with optical encoders to be run on-line with a
PDP-8. Some considerations, which now seem obvious, came
to light only gradually during the course of the work. These
include: devoting considerable time to the planning stage of
the work to try to anticipate all likely needs, weighing the
advantages of hardware and software as a means of implementing
each part of the interface, and in the case of a complex interface, balancing the cost of hardware against purchasing additional computing power. Examples to illustrate these points
wi II be given and our present views on a reasonable hardwarel
software ba lance.

1. Defence Research Establishment Toronto, Downsview,
Ontario, Canada
USE OF ITERATIVE PROCESSES IN EVALUATION OF
STRESSES IN STATICALLY INDETERMINATE SYSTEMS
OF ELASTIC BARS

2. Harvard University, Department of Psychology,
Cambridge, Massachusetts
3.

Digital Equipment Corporation, Maynard, Massachusetts

Dr. Adolph Feingold and Herbert R. Alcorn
University of Ottawa
Ottawa, Ontario, Canada
The problem is statically indeterminate and results in a nonlinear system of equations which does not admit of a closedform solution. The ob ject of this paper is to present an iterative process suitable for computer application which may also
be conveniently used in solving other simi lar problems.

A SIX-CHANNEL MULTIPLEXER FOR THE PDP-8
DATA BREAK FACILITY
R. Krishna
University of ;askatchewan
Saskatoon, Saskatchewan, Canada

A REMOTE I NTERFACE FOR A PDP-8
A six-channel multiplexer for use on the data break facility
of the PDP-8 computer is described. It is designated MPX-1
and functions provided are very similar to those available in
Mu Itiplexer type DM-01 manufactured by DEC. However, the
internal organization of MPX-1 differs significantly. Unlike
DM-Ol which uses one modu Ie per bit for data and data address multiplexing, MPX-1 uses one gate per bit. As a result,
modules onthe required channels alone need to be plugged in.
This results in a more economical and flexible design. Important timing considerations for successfu I multiplexer operation
and how conservative timing margins are achieved in the MPX-1
are described.

Pierre Goyette
University of Ottawa
Ottawa, Ontario, Canada
This paper discusses the design and construction of an interface
that allows the computer to be used at a remote location joined
to the computer by a two-way commun ications Iink. The remote interface allows for 16 I/o channels and accommodates
an interrupt-like action. The communications hardware was
built using integrated circuits wit h a floating common to
achieve a match between the two sets of logic levels. Trans-

mission rates cah be varied. Since one of the prime requirements was programming ease, the design chosen was far from
the simplest in terms of hardware.

PDP-S (DISC) OPERATING SYSTEM WORKSHOP
Roger Pyle, Chairman
Digital Equipment Corporation
Maynard, Massac husetts

ON-LINE PSYCHOACOUSTIC EXPERIMENTATION
WITH A MI NIMAL PDP-sis

This lecture and discussion session is devoted to a presentation
of the design philosophy of the PDP-S Disc software. The
primary features exhibited are ease of use, increased thru-put
and user liberation from operator pane I switch dependency.

C. Douglas Creelman
Department of Psychology, University of Toronto
Toronto, Ontario, Canada

The following topics wi II be discussed:
An interpreter and operating system has been designed to run
observers in auditory signal detection and recognition experiments with a wide range of experimental designs possible. Control of durations of events is critical, and sets of II simu Itaneous"
events must be capable of being chosen. Duration control is
through a hardware c lock which drives a counter set under
program control. The c lock is connected to the program interrupt. The program uses the time the c lock is counting to
piace a subsequent set of lOT instructions immediately below
location f1 so the occurrence of an interrupt is followed as
closely in time as possible by a new set of events. Inc luded
in the system is facility to use PEST (Parameter Estimation by
Sequential Testing) to set stimulus parameters as a function of
recent observer responses; a procedure which reduces experimental time considerably.

1. The philosophy behind the monitor development and the
benefits to the user.
2. The user mon itor commands and interna I structure of the
monitor, including the core requirements, limitations, extensions, and I/o device handling.
3. The standard system programs attached to the disc system,
both for 4K memory and extended memory. A complete discussion wi II be given describing the way programs are saved
on the disc, the general usage of the disc as a program storage
and data fi Ie storage device.

THE WESTERN MULTI-COMPUTER SYSTEM
George Lake
University of Western Ontario
London, Ontario, Canada
The paper describes a combined remote access batch processing
system involving two computers directly coupled. The system
exploits the advantages of both machines.

PDP-9 OPERATI NG SYSTEM WORKSHOP

DECUSCOPE HAS BEEN PUBLISHED SINCE APRIL
1962 AND IS THE OFFICIAL NEWSLETTER FOR
DIGITAL EQUIPMENT COMPUTER USERS SOCIETY,

James Murphy, Chairman
Digita I Equipment Corporation
Maynard, Massachusetts

IT IS PUBLISHED PERIODICALLY AT THE DECUS
OFFICE, DIGITAL EQUIPMENT CORPORATION,
MAYNARD, MASSACHUSETTS,
TELEPHONE:

This lecture and informal discussion period is directed towards
the design philosophy of the PDP-9 ADVANCED SOFTWARE
Operating System which centers on use r convenience and
optimum core util ization.

EDITOR:

1. The comprehensive, device independent, input/output
programm ing system wh ich inc ludes hand lers for all the standard
peripheral devices.
2. The expansion and special ization capabi Iities ofthe system
to utilize all central processor and standard or non-standard
periphera I options.
3. The keyboard control for automatic storage, retrieval,
loading and execution of a II system and user programs.
4. Complete error analysis at monitor,
system program levels.

MRS, ANGELA J, COSSETTE, DECUS

CIRCULATION:

The subtopics wi II be:

input/output and

AC 617, 897-8821, EXT, 414

2,800 COPIES PER ISSUE

PROGRAMMING NOTES

2. The exact format must be followed; the pseudo-instruction
TEXT must be followed by a space, a delimiting character
(! in the example given), the text itself, and a repetition of
the delimiting character.
-- ---

TEXT FACILITY FOR USE WITH THE PDP-8

3. There is no provision for storing CR or LF in th is system.
If either of these is required, they may be generated in the
final text print-out by using % to give a CR and # to give a
LF. No CR or LF wi II be executed in the ASC II Iisting by
these characters; the punch shou Id be turned off, CR and LF
operated as required I and the punch turned o~gain to produce CR and LF in the ASC II text. For example, to produce
in the fi na I text:

David J. Dewhurst
Department of Physiology
University of Melbourne
Parkville: Victoria: Australia
Frequently it is required to generate printed text in the course
of executing a program. By far, the most convenient way of
doing this is to use the MACRO-8 text facility to introduce
messages into an ASCII program and to use a somewhat modified version of the Alphanumeric Message Typeout program
(Digital-8-18-U) to cause the message to be printed out when
the program is executed.

THE CAT SAT
ON THE MAT
the program given above wi II be modified as

An ASCII listing of this modified program can be found at the
end of this article. It uses addresses 4400 to 4457 inclusive,
se lected so that it can be used in con junction with anyone of
the four parts of the Floating Point Arithmetic Package (Digital8-5-5). It also uses the auto-index register 0017, which must
be avai lable whenever the program is called. In addition,
one other Page 0 address must be used to enter the program
indirectly (exactly the same way as the Floating Point Packages
are entered). It is often convenient to use address 0004 for
this purpose, although this precludes the use of DDT-8 for
debugging. This program must be compi led by the use of
MACRO-8, and the resulting BI N tape is stored for subsequent
use.

*0004
MESAGE, 4400

START,

Following %#, the punch is turned off, CR and LF pressed,
and the punch turned on again.

Examples

The characters represented by the ASC II codes Iisted be low
cannot be hand led by th is program.

The use of the text fac i Iity can best be shown by examples.
The program to type out THE CAT SAT ON THE MAT would
read as follows in ASCII:

Character

ASCII Code

*0004
MESAG E, 4400

*0200
KCC
TLS
JMS I MESAGE
! THE CAT SAT%#
ON THE MAT!
HLT

3,0,0
377
2,07
243
245

*0200
START, KCC
TLS
JMS I MESAGE
TEXT !THE CAT SAT ON THE MAT!
HLT

RUB OUT
BELL
#
%

/TEXT FACILITY (S-lS-U MODIFIED)
*44.0.0
MESS,

MACRO-8 wi II compi Ie this program by storing the text in
stripped ASC II characters, packed two characters per address,
and ending with 00 as a terminating signal. (This will put
HLT at address 0217 in the example given.)
The resu Iting BI N program is loaded, followed by the BI N
tape of the modified Digital-8-18-U program. The program
is started at 0200 when the desired message wi II be typed out.
The following points should be noted:
1. The print routine used by Digital-8-18-U must be initialized by TLS (NOr" by TCF), just as the Floating Point
Package routine must be initialized. Accordingly, neither
routine can be readi Iy used in con junction with the Interrupt
facility.

MSRGHT,

.0
CLA
TAD
DCA
TAD
DCA
TAD
RTR
RTR
RTR
JMS
TAD
JMS
JMP
.0

CMA
MESS
.0.017
I .0.017
MSRGHT
MSRGHT

TYPECH
MSRGHT
TYPECH
MESS+4

(continued)

TYPECH.,

AND
SNA
JMP
TAD
SMA
JMP
TAD
JMP
TAD
SZA
JMP
TAD
JMP
TAD
SZA
JMP
TAD
JMP
TAD
TSF
JMP
TLS
CLA
JMP

MTP,

I ~~17
M4~
.+3
C34~

MTP
M3

Figure 2 shows another possible method. This is simpler and
cheaper than the two previously mentioned. In this method
the address bit buses are connected to the unit address lines
through isolating diodes. If a bit is 0 to establish the correct
address code, the diode in that position is disconnected. For
example, if the address code for Unit 1 is (7754)S, then diodes
from bit 10 and 11 buses to the Unit 1 address Iine wi II be
missing.

.+3
C212
MTP
M2

MASK77,

~~77

M4~,
C34~,

~34~

M3,
C212,
M2,
C215,
C245,

(type R123 or similar). The first method requires one module
per address bit, whereas the second method requires one gate
per bit. Ifcost of the modules were the only deciding factor,
the re lative merits of these two methods can be worked out
assuming the required number of channels is known. For example, if on Iy three channe Is are needed, the second method
is obviously preferred because it costs only S 114 for 12 bits
against $156 for the first.

MASK77

.+3
C215
MTP
C245

When Unit 1 is selected, Unit 1 address line is driventoground
and all other unit address lines will be at -3volts. The diodes
associated with Unit 1 can now conduct and drive the corresponding buses to ground. Diodes associated with the other
units, however, remain cut off and, hence, have no effect
on the buses. The effect of this arrangement is that the contribution to the address buses will be only from the selected
address line, and the bus on which there is no diode will remain floating.

.-1
I TYPECH

774~

7775
~212

7776
~215
~245

The address buses are connected to the level inputs of the DC D
gates on the set side of the MA register in the PDP-S. When
these DC D gates are strobed during the CA cyc Ie, any bit
whose bus was left floating wi II be transferred as a "0" into
the MA. From the arrangement shown in Figure 2, it is easy
to verify the validity of the following table.

MULTIPLEXING OF DATA ADDRESS BITS FOR PDP-S
3-CYCLE DATA BREAK FACILITY
R. Krishna
University of Saskatchewan
Saskatoon, Saskatchewan, Canada

UNIT SELECTED

ADDRESS SET UP

----------------------------------------------------High-speed transfers can conveniently be handled by using
the data break facility of the PDP-S. Most of the high-speed
peripherals use the 3-cyc Ie data break. However, as the
PDP-S has onlyone channel avai lable for data break transfers,
it becomes necessary to use a multiplexer if more than one
device has to be connected to the break channel.

(7754)S

----------------------------------------------------2

(0032)S

-----------------------------------------------------

The multiplexer can be thought of as a collection of highspeed switches connecting the information lines from the peripheral devices to the computer in a predetermined order.
The multiplexer is also capable of distributing the signals from
the computer to the peripherals. All necessary signals for a
successfu I data break operation are Iisted in the Sma II Computer Handbook. Because (during a data break) peripherals
can communicate directly with the core, the address for the
location of current interest must be specified by the device.
For a 3-cyc Ie data break, this address is fixed on one address
per device basis and, hence, can be specified by proper wiring.
If a device is requesting access for a transfer, multiplexer
presents the corresponding address only to the computer lines.

(0034)S

----------------------------------------------------4

(0036)S

----------------------------------------------------5

(0070)S

-----~------~-~--------------------------------------

Two possiblemethodsofmultiplexingtheaddressbits are shown
in Figure 1. The first method uses And/Nor gate (type R141
or similar) modules and the second method uses diode gates

ADD0

ADDl

ADD2

ADDll

L
UNl SELECT
UNlADD 0
UN2SELECT
UN2ADD0
UN3 SELECT
UN3 ADD0
UN 4 SELECT
UN4ADD0

_1'!.N~QPll

UN5 SELECT
UN5ADD0

_l!...N~A.Q..oll

•

I
I

I
!

",lAOO"~ 1",2""'''~ :,"5ADD"~
, t--cP !~
~_

UNlSELECT

UN2SELECT

METHOD 1
METHOD 2

Figure 1.

o--4--"'--_4-_-J'L...._--A_ _"'-_ _---<"'>

ADD 0

o-~~'---~-~~-~--~---<"'> ADD I

o-~~'---~-~~-~--~---<>ADD2

o-~-4'---~-~~-~---~---<"'>ADD3

()-........--1~-+--J'1'---"'---1'-----<>

ADD 4

()-~~L---~--J'~-~---~---<>ADD5

()-_~~~~--J'~~~--~---<> ADD 10
()-_~'----~--J'~-~--~-----<"'> ADD

UN I
SELECT

•

UN2
SELECT

UN3
SELECT

UN4
SELECT

Figure 2.

UN5
SELECT

••• '

~~
'

UN5SELECT

OADDll

integration routine (Runge- Kutta) or someth ing sim i lar.

PUNCHING BINARY TAPES ON THE L1NC-8

Information on routines of this type which are avai lable wou Id
be appreciated.

L. N. Law
Department of Psychology
Institute of Psychiatry
London, England

H. Kyle Collins, Jr.
Department 72-15, Zone 12
Lockheed-Georgia Company
Marietta, Georgia 30060

A problem occurs when attempting to punch a binary tape on
the LI NC-8 since all zero characters are om itted. This is due
to the PROGOFOP subroutine, TYPEIT, which uses the value
of the output character as a flag to indicate that I: ~ Teletype
is busy, and zero flag to indicate that the Teletype is free.
Thus, the next character in a string is loaded immediately on
top of any zero.

LETTERS
II

A solution is to use 7777 as a II busy" flag, independent of the
character value. A modified TYPE IT, which uses three fewer
locations, is as follows:

Dear Mrs. Cossette:

liThe letter from Omega-t Systems Incorporated requesting information about a digital analog simulator for the PDP-8 was
of considerable interest to us.

PRINT=21
"Dr. T. G. Coleman and I recentlydevelopedsuch a simulator
for another small computer, the IBM 1401, and plan to use
the same techniques to fit the simulator into the PDP-8 and
PDP-9. The system is known as PAS(150) for the Physiologica I
Analog Simulator and currently will handle up to 150 analog
blocks.

*1501
1501
1502
1503
1504
1505
1506
1507
1510
1511
1512
1513
1514

0000
2021
5306
6041
5304
6046
7240
3021
5701
0000
0000
0000

0
ISZ PRINT
JMP OKPRINT
TSF
WAIT,
JMP .-1
OKPRI NT, TLS
STA
DCA PRI NT
JMP I TYPEIT
0
/THREE
0
/SPARE
0
/LOCATIONS

TYPEIT,

Enclosed are copiesof two reprints describing the system. We
expect a more detailed article to appear in a future issue of
Computers and Biomedical Research.

"Wewould liketoknow of any other persons interested in such
an analog simulator as well as any group who might like to
prov ide some research support to further deve lop the system
for conversational mode operation.
Cordially,

HANTED

Fred R. Sias, Jr.
Research Instructor
The University of Mississippi Medical Center
Jackson, Mississippi 39216"

I am interested in programs for man-machine "conversation"
via the teletypewriter, in English-like sentences, for experiments in computer-aided behavioral therapy (like Colb/s,
Weizenbaum's, etc.), for information retrieval and library
searching (like M. M. Kessler's, Bobrow's, etc.), and for
simulation 0 f models of inductive inference and cognition
(like the work of Feigenbaum, Mursky, etc.). We have a
PDP-8 connected as a satellite to the University's 360/67 via
a 220 cps line. We also have a SOROBAN high-speed card
reader, high-speed paper-tape reader, high-speed tape punch,
and an I/o analog converter attached. I would also like to
know about programs now under development or in planning
in this connection.

Dear Mrs. Cossette:

liThe Gorman-Wolfberg technique for clearing all of memory
in the PDP-8 (DECUS 5/8-27a), inc luding the eight- instruction
program itself, can be slightly improved in efficiency by the
following minor alterations:
Absolute Clear

I am also inferested in any programs which store psychological
or educational tests, accept on-line responses from subjects,
and score these.

Location

Octal

f1f1f1f1

3f1f1f1
741f1

2772
2773
2774
2775
2776
2777

Manfred Kochen
Assoc iate Professor
The University of Michigan
Mental Hea Ith Research Institute
Ann Arbor, Michigan 48104

3f1f1~

3376

2f1f1f1
34f1f1
5372
3374
34~,0

Symbolic

3f1f1f1
SKP
DCA .+3
ISZ f1
DCA I f1
JMP .-4
DCA .-3
DCA 151

/START, AC=,0

"This reduces the execution time by about 10%, at ro additional cost in progral"1 space. Even t~i$ record can be beaten,

As part of our work on the PDP-8, we want to solve a set of
differential equations. In order to solve these we need an
10

Absolute Halt

however, bya basicail y different technique for absolute clear.
which also requires only eight if'lstructions, all conveniently
contiguous, and which is more than twice as fast:
Location

Absolute Clear
Location

Octal

Symbolic

7771

3776

DCA I .+5

7772

2011

IC7

7773
7774
7775
7776
7777

2376
5371
3374
%%%1
4411
3411

ISZ .+3
JMP .-3
DCA .-1
%%%1
JMS III
DCA III

%%%%

1...Ji:-

%%1%
%%11
7375
7376
7377

/START, AC=%

11
II

74y5%
74y51
74y52
%%%%

(Assumes locations
%%13 through 73t:4
clear.)

Octal

Symbolic

767yj
341%

767%
%%11
DCA I

1,0,0,0

TAD ,0

3411

DCA I 11
TAD y5
JMS I 11
DCA III
HLT

y5%1l

ly5y5y5
4411
3411
74%2

ly5
/ST AR T, AC=y5

Frederick R. Kling, Research Psychologist
Educational Testing Service
Pri nceton, New Jersey 08540

JlSince it is puzzling just why anyone would want to clear all
of memory, it might serve a usefu I purpose for readers to share
their reasons for deliberately wiping out RIM, etc. Our part i cu Iar reasons a II stem from a prob Iem we were hav i ng a few
weeks back with the night watchman. It seems that he had
discovered howto enlivenhis nightly rounds by turning on the
PDP-8, pressing random control keys, and communing in some
private, esoteric manner with the blinking lights. Inevitably,
he managed to bomb RIM and everything else. When both
pol ite and nasty notes had fai led to deter him, we resorted to
an absolute memory clear in hopes that the resulting dull, unchanging panel countenance wou Id strike him as non-communicative, thus terminating the nightly dialogues.

MODULE NEWS
At this writing approximately 65 users have appl ied for membership in the Module Users Group of DECUS. Below is a
listof the areas of application alongwith types ofmodules and
computers used by these members.

II For severa I nights a II went we II. Each morn i ng we found memory entirely blank, just as we had left it. One memorable morning, however, we discovered the following: Switch register set
II
at 2000, hash all through memory, and IICOGITO ERG typed
neatly on the teletype which was still switched on line. Our
best efforts at reconstruction suggest that our watchman started
the computer with memory all c lear, raised bit one in the switch
register as the computer cyc led through core, and then pressed
stop, deposit, and continue in thatorder--probably only once,
though we cannot be certain. We suspect he had a joyful reunion with the blinking panel lights but turned the computer
off in panic when it commenced typing out its precious message.

TYPES OF FLIP CHIP MODULES USED
Module Type
R series
A series
B series
K series
M series

% of Appl icants
97%
45%
34%
6%
3%

TYPES OF DEC COMPUTERS USED
Word Length

II What was the random address where he deposited ISZ %? Did
he deposit it more than once? And, if so, after how long an
interval? Was the computer about to concur with Descartes'
famous dictum? Or was it about to reach some more astounding
conc lusion?

12 bits
18 bits
36 bits

% of Applicants
63%
44%
6%

COMPUTER INTERFACES AND PERIPHERALS

II We may never know--our watchman has vanished, leaving
no trace. Since then, we have spentmany longhours clearing
memory and randomly inputing a single bit one (ISZ f5), producingmagnificentpanel displays for uptotwenty minutes and
more but nary a peep from the te letype. (Input locations 2%%
and 2%1 are excellent examples.) Recently we have begun
randomlyinputtinga second bitone afterthe panel lights have
stabilized. One Bit One and Two Bit One Artificial Intelli.gence Tests we call these experiments, and we earnestly sol icit
help in conducting them from anyand all PDP-8 users interested
in recovering the conditions that precipitated that fleeting
moment of cosmic sign ificance which our watchman, poor man,
was unable to comprehend.

Type of Application
A-D and/or D-A
Magnetic Tape
•Scope Display
Real Time Clock
Joining two digital computers
Data Acquisition Systems
Plotter
High Speed Data Channel
Multiple Teletypes
Pu Ise Height Ana Iyzer
X Ray Instrument
Punched Card Equ ipment

•• Oh, yes. One other reason we have found for calling Absolute Clear. It enables us next to call Absolute Halt:
11

Shaft Encode'
Drum Memory
Paper Tape
Microdensitometer
Data Transmission
Joining digital to analog computer
QRS Flag
CRAM
F lame Cutter
Milling Machine
Hewlett Packard Counter
SMP (Scanning-Measuring Projector)
Brain Scanner
Stepping Motor
WANG LOCI - 2
Measuring Machine

NOTE ON NEGATIVE INPUT LEVEL CONVERSION
R. Krishna
Department of Electrica I Engineering
University of Saskatchewan
Saskatoon, Saskatchewan, Canada
It is not uncommon for DEC Computer users to interface equipmentwith logic voltage levelsotherthan -3and Ovolts. When
it is a matter of converting higher negative voltages to DEC
Leve Is, it is logical and customary to use Negative Input Converter W511 modu les . Recently, we looked into methods of
gating thirty-eight -6V level signals into the PDP-8 accumulator. This, of course, could have been done with 19 W511
modu les for level conversion followed by 38 inverters before
gating with R123 modu les into accumu lator. The cost of 19
W511 modu les alone wou Id have been about S325 not ignoring
the fact that they occupy 19 slots on the mounting pane I. This
seemed out of proportion to the 7 R123 modu les which actually
perform the gating, at a cost of S140. In addition, use of
W511 modu les for level conversion makes it necessary to include 6 R107 modules at $150 to restore the correct polarity.
All this amounts to about $475 extra as a pena Ity. This convincedusto seek some other method of level conversion which
would be more compact and economical. The possibility occured to us to use W002 and R001 modules to achieve the
level conversion without inversion. The working principle of
the proposed method is very simple, as explained with the aid
of the diagram given below.

Ultrasonic Flaw Detector
AMP Credit Card Reader
Teaching Machine
Electrochemical Control
VIDICON Input
Communications Terminal
Auto Call Unit
Tacti Ie Perception Unit
Data Set
Process Control
Production Machinery
Disc Memory
Core Memory
STAND ALONE SYSTEMS

Forward conduction of silicon diodes D3 throu!!;Jh D6 provide
the -3V logic supply. If the input is at -6V, diode Dl is
reverse biased and the output wi II be at -3V because D2 can
conduct through R1 . When the input is at ground potential i
the output also tends to assume ground potential because Dl
can now conduct through R1 . Under these conditions, diode
D2 is reverse biased.

Type of Applications
Computer, Special Design
Signal Generator
Analog Mu Itiplexer
Sample and Hold
Clock
Noise Generator
Animal Behavior Tester
Integrated Circuit Tester
Television Encoder
Time Code Generator for 16 mm fi 1m
FM Receiver to Mag Tape Interface
Binary-Decimal Converter
PCM Simu lator & Decoder
Radar Range Error Detector
Controls for Automatic Machinery
Analog Data to Punched Tape Converter

This method of leve I conversion seems attractive, as long as
one is aware that load current flows through Dl when the input is at ground and wi II resu It in a voltage drop a:ross it.

-15V

Input
D3
D4
D5
D6

MODULE USERS - SEND IN YOUR MODULE APPLICATION NOTES FOR PUBLICATION. MATERIAL DSHEOCUUSLD
BE SENT TO: ANGELA COSSETTE, EDITOR,
,
MAYNARD, MASS. 01754.

- --

!!0~2 ~

MODULE APPLICATION NOTE

The same complement of DEC Flip-Chip modules can be used
to perform each of the above types of experiments. The basic
function being performed is the measurement and control of a
time interval. Figure 1 is a block diagram of a variable ratio
scheduler. Two separate binary counters are used! one to count
responses and the other to count reinforcements. The response
counter is reset by the output of a digital comparator which
compares the two counters. In this way! the number of responses required to produce a reinforcement can be made proportional to the number of reinforcements that have occured.

BIOMEDICAL RESPONSE SCHEDULING
Experiments involving the response behavior of animals may be
classified broadly as follows:
Fixed Ratio Schedu les
In these experiments, the animal is rewarded or "reinforced"
only after it has responded a fixed number of times. That is,
the ratio between responses and reinforcements is fixed. When
the fixed ratio (FR) is 1, the subject isbeing given "Continuous
Reinforcement", but more often the FR is much greater.

Module List
W051.
.1
W501
• ••• 1
R603
•••• 1
R202 . . . • • •
.. 5
R131
• 1

Variable Ratio Schedu les
In these experiments, the number of responses required for each
reinforcement varies in a fixed, sequential order. That is to
say, the ratio changes after each response. Typically! the
ratio may vary from one to ten during ten sets of responses.

Spectra Accumu lation
The experimenter is sometimes interested in obtaining a histogram of response intervals. This is usually part of still another type of experiment in which reinforcement occurs only
when the subject responds at a rate below a specific value!
usually expressed in seconds. This is known as Differential
Reinforcement of Low Rates (DRL). Typically! up to 20 time
intervals are investigated! and up to 100 events are recorded
in each time interval. This involves the use of twenty 7-bit
counters and twenty delays! plus the associated control circuits.
The following is a list of modules required to construct such a
20 channel analyzer:

Fixed Interval Schedules
In these experiments! reinforcement does not occur unti I some
time after the last reinforcement regardless of the response
activity. In addition, a I imit may be imposed o~ the p~r~od
during which the subject may be reinforced. ThiS condition
is referred to as a Fixed Interval with Limited Hold.
The hardware required to perform such experiments usually
consists of a variable-length counter which is initialized by
a reinforcement and a delay to control the hold time.

R202
R302
W051 •
R602

Variable Interval Schedules

.70
. 12

1
1

In these experiments! the interval during which responses are
not reinforced is varied after each reinforcement.

R202(2)
BINARY COUNTER
(4 BITS)

SUBJECT

NO. OF
REINFORCEMENTS

\
I

SWITCH
CLOSURES

WSOl

R603
NO. OF
RESPONSES

FIG. 1 - VARIABLE RATIO SCHEDULER

NEW DECUS MEMBERS
PDP-l DELEGATES

PDP-8 DELEGATES (Continued)

Raymond P. Holler
ITE K Corporation

Eldon L. Bolduan
Ca II-A-Computer

Herbert J. Mainwaring
Cadi lIac Motor Car

PDP-4 DELEGATES

C. W. Bright
Defense Research Estab Iishment
Canada

Manager
Esso Petroleum Company, Ltd.
England

Dr. J. G. Burns
Edinburgh University, Scotland

Richard Marlowe
March Photo Setting Inc.

Michael D. Busch
Cognitronics Corporation

Maurice J. Moroney, Jr.
NASA/Electronics Research Center

D. E. Clark
Un iversity of Manchester, England

D. E. Nunn
Road Research Laboratory
England

Timothy C. Rand
University of Michigan

PDP-5 DELEGATES
Jerry D. Ford
Electronic Associates, Inc.

PDP-6 DELEGATES
John J. Ki Iduff, Jr.
Brookhaven National Laboratory
John B. Locke
Rutgers University
K. Muller
Universitat Bonn
Germany

PDP-7 DELEGATES
A. Bishop
Royal Radar Establ ishment
England

Carl D. Cole
Western Electric Company

Leif Ohlsen
Autonemi AB, Sweden

H. E. Dawson
Imperial Oi I Enterprises Ltd.
Canada

Richard E. Palmer
State-Times & Advocate

Alick Elithorn
Medical Research Council, England

Jack W. Ponton
University of Edinburgh, Scotland

Ivan Pfennig
Fairchild Semiconductor

Richard L. Quillin
Call-A-Computer

Lex Fulton
Morton Newspapers, Ltd.
Northern Ire land

J. C. Ribes
Observatoire de Meudon, France

Joan Hamill
Transitron Electric Corporation

Allan H. Robbins
Manitoba Institute of Technology
Canada

Robert A. Hoffman
The Up john Company

T. F. Rogers
National Research Council, Canada

P. Howard
Atom ic Energy of Canada, Ltd.

Steve Seccombe
Benson- Lehner Corporati on

R. E. Hummer
University of Maryland

M. Seneret
La Radiotechnique RTC, France

Gerard L. Kearns
Picker X-Ray Corporation

Dr. Hideo Seo
University of Illinois

T. Axford
University of Birmingham
England

Henry P. Ki Iroy
Potter Instrument Company, Inc.

Sidney Si Iversher
California State College

Norman R. Be II
North Carol ina State University

Bruce M. Kolodny
Compat Corporation

Dr. Howard H. Sky- Peck
Presbyterian-St. Luke1s Hospital

Aleksander Bi linski
Perkin-Elmer Corporation

David Lange
University of California

Bland Smith
Tucson Newspapers Inc.

Jennifer Bostock
Com-Share, Incorporated

W. T. Lyon
Aluminum Company of America

D. N. Spinelli
Stanford University Medical Center

PDP-8 DELEGATES
John C. Alderman, Jr.
Georgia Institute of Technology
R. J. Alfandre
Standard Programs Corporation
Thomas Allen
Whirlpool Corporation

PDP-S DELEGATES (Continued)

PDP-SIS DELEGATES (Continued)

Steven J. Stadler
Grason-Stadler Company, Inc.

Gino Carli
Sandia Corporation

R. W. Prowse
Brunei University, England

Ross Tooley
Plessey Company, Austral ia

Dr. Glen D. Christofferson
Chevron Research Company

A. Reimer
Wh iteshe II Nuc lear Research Est.
Canada

Mssr, Trof! moff

1;>" ... ,.,I,.j r,,~

Societe Rhone Pou lenc, France

Beckman Instruments, Inc.

W. E. Tubbs
Stanford University Medical Center

Charles R. Conkling, Jr.
Infotec, Inc.

Thomas M. Valentine
Atomic Energy Authority, England

John W. Davidson
Durham College, Canada

Thomas C. Valuo
Benson- Lehner Corporation

Steven M. Davidson
N.S.M.S.E.S.

F. A. Van Hall
Institute for Nuc lear Physics Research
Netherlands

Justus Dunlap
Northwestern University

P. Vladimiroff
Texas Instruments, Ltd., England
D. G. J. Vogel
University of Manchester, England
Mrs. J. Wadsworth
Usher Institute of Socia I Medicine
Scotland

I\'VII",.. 1'-'1

. . . l-~ ...

' - " VI II t-'I VI I

Matthew L. Fichtenbaum
General Radio Company
Eugene Heal
Victor Comptometer Corporation
Floyd L. Hughes
National Naval Medical Center

Lawrence A. Rempert
RCA Laboratories
Hermann Riedl
Siemens-Ag, Germany
Dr. R. E. Robinson, III
Bowman Gray School of Medicine
J. Schuiling
N. V. Philips Co., Netherlands
Dr. Lothar Seifert
Siemens America Incorporated
Per Skaarup
Atomic Energy Commission, Denmark
Allen H. Smith
Hoover High School, California
Charles W. Smith
General Dynamics Corporation

Dr. J. P. Hurley
U.S. Naval Radiological Defense
Laboratory

F. E. Stafford
Northwestern University

Ernest A. Kruger
Data Control Systems

Les lie Thomas
Telecontrol Corporation

Birger Kvaavik
Axel Johnson Institute, Sweden

David H. Tyrell
Middlesex County College

R. F. LaFontaine
C.S.I.R.O., Aust:-alia

Richard Desper
U. S. Army Natick Laboratories

Ann Maybrey
University of Liverpool, England

Dr. R. G. Westberg
Philips Electronics Instruments

Dr. Robert H. Mc Kay
University of Hawaii

Andrew B. White
Geodyne Corporation

Christopher W. Parfitt
College of Technology, Ireland

PDP-9 DELEGATES

R. Willis Parlin
University of Minnesota

James J. Anderson
Minneapolis-St. Paul Sanitary District

Wendell Peacock
Harvard Medical School

J. E. Braun
California Computer Products, Inc.

N. C. Baust
The Plessey Company, Ltd.
Austral ia

Terry H. Pocock
Data Management Systems, Canada

R. E. Brown
British European Airways, England

Mrs. K. A. Porter
Cumberland Hotel, England

Craig A. Denison
Lawrence Radiation Laboratory
University of California

Dr. Bernard Weiss
University of Rochester
School of Medicine & Dentistry
Dr. W. E. Wilson
Batte Ile- Northwest

PDP-SiS DELEGATES
James G. Adams
Western Electric Company
Albert L. Adell
Western Electric Company
A. P. Baerg
National Research Counci I, Canada
R. A. Bailey
Defense Reg istry, Austra Iia
Tom Barrett
Infotronics Corporation

PDP-9 DELEGATES (Continued)

MODULE USERS GROUP MEMBERS

Richard M. Dunn
New England Power Service Company

Prof. C. W. Warren
Ohio State University

James J. Balliet
Western Electric Company, Inc.

Dr. Robert E. Dustman
Veteran's Administration Hospital, Utah

PDP-10 DELEGAT ES

Frederic R. Boswell
Case Institute of Technology

James A. Field
University of Waterloo, Canada

Roderick A. MacLennan
Sikorsky Aircraft

Wa Iter R. Burrus
Tennecomp, Inc.

Michael J. C. Hu
Stanford Linear Accelerator Center

L1NC-8 DELEGATES

Joseph G. Donnelly
National Security Agency

Ir. E. R. Koo i
Leiden State University, Netherlands

Dr. Stan ley A. Bri Iler
University of Pennsylvania Hospital

Tor Ling jaerde
European Organization for Nuc lear
Research, Switzerland

Gerald Cedarquist
Cooley Electron ics Laboratory
University of Michigan

Tony Ferrera
Stanford Research Institute

Bruce D. Link
Oregon Research Institute

Mrs. Mary Allen Clark
Washington University

T. T. Fong
Canadair, Ltd, Canada

C. B. Lou
California Computer Products, Inc.

Dr. D. L. Filmer
Purdue University

V. W. Gerth, Jr.
Washington University

Joseph T. Massimo
Brown University

R. L. Hershman
Naval Electronics Laboratory Center

Larry Green
University of California

Dr. Suresh C. Mathur
Lowe II Technological Institute

Miss Carole Kennedy
Lederle Laboratories

Vahe Guiragossian
Columbia Un iversity

Dr. Douglas Miller
Haverford College

Dr. Lewis E. Lipkin
National Institutes of Health

David E. Hartsig
Information Control Systems, Inc.

K. R. Morin
St. Pau I's Hospital, Canada

Joh n W. Moore
Duke University Medical Center

Howard E. Klausmeier
S. Sterling Company

John Pluth
California Computer Products, Inc.

Dr. Marvin A. Sackner
Mount Sinai Hospital

Gary B. Morgan
Idaho Nuc lear Corporation

Hamish F. Ross
University of Birmingham, England

Jan Spruit
Fe Is Research Institute

Donald W. Roland
Beckman Instruments

E. L. S igu rdson

Dr. M. G. Strobel
Dalhousie University, Canada

Stephen Russe II
Stanford University

Lawrence J. Van Cura
University of Wisconsin Medical
Center

Bruce Arne Sherwood
California Institute of Technology

University of British Columbia, Canada
Richard A. Simmermacker
California Computer Products, Inc.
Prof. B. M. Spicer
University of Melbourne, Australia

David E. Wood
Un iversity of Michigan

Donald R. Fanshier
Lawrence Radiation Laboratory
University of California

Paul A. Tharman
General Electric Corporation

Gordon E. Stokes
Idaho Nuclear Corporation

B. Michael Wilber
Stanford Research Institute

Dr. M. M. Taylor
Defense Research Estab Iishment
Canada

Frank Zimmer
Siemens America, Inc.

Rudolph F. Trost
University of Pennsylvania
Moore School of Electrical Engineering
16

DIGITAL SOFTWARE NEWS
sent on Software Trouble Report Forms, which are avai lable from
the Program library (address below). For more efficient service,
the following information should be included.

This newsletter is intended for PDP-5/8, 8/S, 7, 9, and UNC-8
users. It is compi led and published by the Software Maintenance
Group and contains information about the following.
1. Software Problems and Corrections:
Various problems with
Digital's standard library pragrams and manuals are discussed and
solutions given. In cases where no corrections are avai lab Ie at
the time of publication, they wi II be inc luded in a later newsletter.

Type and configuration of machine.

2. Brief but concise description of the problem. Include the
name and date of the Digital library program in use at the time
of problem.

2. Programming Notes: Various programming aids are discussed,
generally in response to customer questions • An attempt is made to
supplement the manuals where necessary. Suggestions for subject
material of these notes should be directed to the Software Maintenance Group (address be low).
3. A list and brief description of new and/or revised software
which is avai lable from the Program Library.

Listing of user program in use at time of problem.

listing of erroneous results and/or error messages.

Contents of AC and PC where applicable.

New and revised software, manuals, and Software Trouble Report
forms are avai lab Ie from the Program Library. When ordering, inc lude the document number and a brief description of the program
ormanual desired. At this time there is no automatic updating of
revised programs and manuals. They wi II be shipped only on request. Revisions and notifications of updates wi II be published
in this newsletter, which will continue tobe part of DECUSCOPE.
Direct all inquiries and requests to:

The Software Maintenance Group is responsible for the maintenance
of Digital's standard library programs. There is a software support person at most of the regional and district sales offices and
initial reports shou Id be made to them. In cases where they are
unavailable, reports should be directed to:
Software Maintenance Group
Digital Equipment Corporation
146 Main Street
Sui Iding 12 Second Floor
Maynard, Massachusetts
It is strongly suggested that all problems referred to this group be

Program Library
Digital Equipment Corporation
146 Main Street
Bui Iding 12 First Floor
Maynard, Massachusetts 01754

I. PDP-5, 8, 8/S

SOLUTION: This error can be corrected by changing five locations in core before building the Monitor on the DISC.

A, PROGRAMMING PROBLEMS

The locations to change are underlined be low. The other instructions
are given only as reference points and should remain as they are.

PROGRAM: PDP-8 DISC SYSTEM BUI LDER (DEC-08-SBAB)
On page 1, section 3, of the System Bui Iderwriteup (DEC-08-SBAB)
there are instructions for bui Iding a monitor. After completing step
c (Load BUI LD using Binary Loader), make the changes indicated
below. When the five locations have been changed and checked
continue with step d in the writeup.

PROB LEM: An error has been found in the DI SC Monitor Bui Icler.
This affects only those systems equipped with more than one disc
(i .e., one DF32 and one, two, or three DS32s) and will cause
fai lure in sue h systems.

CURRENT CONTENTS:
0306
0307
0310

1022
2731
4450

DBLK1
ISZ I SMFIX
JMS I DIOX

0333
0334
0335
0336
0337

0514

BLOCF, BLOC

/SET INDICATOR TO ADJUST FINAL BLOCK OF SAM STRING TO
/GIVE "SCRATCH AREA"
/WRITE THE "SAM" BLOCKS ONTO THE DISC.

{PREVIOUSLY UNUSED BY MONITOR

CHANGE TO:
0306
0307
0310

1022
5334
4450

DBLK1
JMP 0334
JMS I DIOX

0333
0334
0335
0336
0337

0514
2731
7124
3555
5310

BLOCF, BLOCK

/WRITE THE "SAM" BLOCKS ONTO THE DISC.

ISZ I SMFIX
STL RTL
DCA I ONEU3
JMP 310

B, PROGRAMMING NOTES
1. The following is a modified RIM Loader which will use the
high speed reader to load the Binary Loader and other RIM format

ABS.
ADDR.

OCTAL
CONTENTS

7756
7757
7760
7761

6014
6011
5357
6016

7762
7763
7764
7765
7766
7767
7770
7771
7772
7773
7774
7775
7776
7777

7106
7006
7510
5374
7006
6001
5367
6016
7420
3776
3376
5357
0000
5301

tapes.

The starting address is 7756, as in the low speed version.

SYMBOLIC
BEG,

TEMP,

RFC
RSF
JMP .-1
RRB RFC

/c lear flag and fetch char. into buffer
/skip when flag=l

CLL RTL
RTL
SPA
JMP TEMP-2
RTL
RSF
JMP .-1
RRB RFC
SNL
DCA I TEMP
DCA TEMP
JMP BEG+1
0
0

The following is a collection of execution timings of Math

/read buffer into AC, get next char. into
buffer
/rotate channe I S into
/ACbitO
lis it leader
/yes clear AC
/NO rotate c hanne I 7 to LI NK

/Iink set=origin
/store data
/store address
/next word
/temporary storage
/JMP to start of BIN loader

plicand is 0, the multiplication is bypassed. In this case,
execution time will be 22.5 jJsec if the multiplier is positive, and 24.0 jJsec if the multiplier is negative.

Routines for the PDP-S and PDP-S/S.
Si~gle Precision Square Root Subroutine - DEC-OS-FMAA

Maximum - Maximum execution time occurs when the sign of
the product is negative. This time is approximately 71 .0 jJsec.

Execution Time - Timing Equation - If the answer is N, the
time for the subroutine is (30 N(25.5)} jJsec.

Average - 66 jJsec

Single Precision Signed Multiply Subroutine - DEC-OS-FMBA
Execution Time - Without EAE

Double Precision Signed Multiply Subroutine - DEC-OS-FM DA

Minimum - When the subroutine discovers that the multiplicand is 0, it bypasses the multiplication loop. In this case,
execution time is 25.5 jJsec if the multiplier is positive, and
27.0 jJsec if the multiplier is negative.

Execution Time - Without EAE. As is true for Single Precision
SignedMultiply, the execution time for Double Precision is a function of the number of binary l's in the operands.
Maximum - The maximum execution time is 1 .605 msec.

Maximum - Maximum execution time occurs when the sign
of the product is negative and the multiplier consists (in binary) of all l's. This time is approximately 350 jJsec.

Average - Average time wi II be around 1 .4 msec.
Execution Time - With EAE

Execution Time - With EAE
Minimum - When both the multiplicand and multiplier ore positive;
24S.3 jJsec.

Minimum - When the subroutine discovers that the mu Itipl ier
is 0, the multiplication is bypassed and execution time is
9 iJsec. Also, when the subroutine discovers that the mu Iti-

Average - 270.0 iJsec

Average - With EAE. The EAE floating-point multiply is at least
1100 fJsec faster than the non-EAE version. The EAE floatingpoint divide is at least 1165 fJsec faster than the non-EAE version.
The Normalize routine, used by all arithmetic routines, may be
summari zed ~

Single Precision Signed Divide Subroutine - DEC-08-FMCA
Execution Time - Without EAE
Minimum - 58.5 fJsec (Divide check).

Number of
Shifts

Maximum - 478.5 fJsec.
Average - 460 fJsec. (approximate Iy).

Execution Time - With EAE

1
2
12
24
34

Minimum - When the dividend and the divisor are both positive
and divide overflow occurs because the high order dividend is
greater than or equa I to the divisor; 46.5 fJsec .

Non-EAE (fJsec)

EAE (fJsec)

45.0
78.0
111.0
445.5
844.5
1174.5

51.0
83.5
84.5
75.0
121.5
131.5

Maximum - When the dividend is negative, the divisor a positive
non-zero numberJ and no overflow occurs; 106.5 fJsec.
The alignment subroutine (add and subtract) may be summarized:
Average - 98.0 fJsec
Number of
Shifts

Double Precision Signed Divide Subroutine - DEC-08-FMEA
Execution Time

1
2
3
12
24

Minimum - 1 .424 msec.
Maximum - 1.705 msec.

Non-EAE (fJsec)

EAE (fJsec)

38.2
78.0
17.2
475.2
952.5

82.0
83.0
84.0
93.0
91.5

Average - 1 .650 msec .

Logical Subroutines (Inclusive & Exclusive OR) - DEC-08-FMIA

Double Precision Sine Subroutine - DEC-08-FMFB

Execution Times - Inc lusive OR requ;res precise Iy 32.0 fJsec.
clusive OR requires exactly 46.0 fJsec.

Ex-

Execution Time
Minimum - When the argument is a multiple of; 70 fJsec.

Arithmetic Shift Subroutines (Single & Double Precision) - DEC08-FMJA

Maximum - Without EAE; 10.6 msec.
With EAE; 2.78 msec.

Execution Times - Time needed fora given shift may be calculated
from the following equations.

Average - Without EAE; 10.4 msec.
With EAE; 2.6 msec.

Single Precision Shift Left
Single Precision Shift Right

Double Precision Cosine Subroutine - DEC-08-FMGB

Sing Ie Precision Shift Right

Execution Time -Calls Double Precision Sine, therefore, in general
Double Precision Cosine averages from 75 fJsec to 93 fJsec longer
than Double Precision Sine.

Double Precision Shift Left
Double Precision Shift Right
Double Precision Shift Right

Minimum - Occurs when the argument is O.
tion time is 55.5 fJsec.

In this case, execu-

Logical Shift Subroutines (Single & Double Precision) - DEC-08FMKA

Four Word Floating Point Package - DEC-08-FMHA
Execution Times - Without EAE. Execution times are very difficulttoestimateasthey greatly depend upon the data on which the
Floating Point package is operating . Generally, average times
are as fo Ilows :
FADD

- 382 fJsec +42(N}where N is the numberof shifts needed
to align the binary points.

FSUB

- FADD time -+42 fJsec.

Execution Times - Time needed fora given shift may be calculated
from the following equations.
Single Precision Logical Shift Right
Double Precision Logical Shift Right

FDIV

- Approximately3.4msec.

FGET

156 fJsec .

FPUT

172 fJsec.

FNOR

168+N(42) fJsec where N is the number of shifts; +84
f-lsec if the argument is less than zero.

FEXT

140.5fJsec.

22.4 + 6.4 N fJsec.
36.8 + 24.0 N fJsec.

C. NEW &REVISED PROGRAMS &MANUALS
I. NEW

Approximate Iy 3.3 msec.

FMPY

22.4 + 6.4 N fJsec.
For Positive data 22.4 + 9.6
N fJsec.
For Negative data 22.4 + 11.2
N fJsec.
40.0 + 20.8 N fJsec.
For Positive data 40.0 + 24.0
N fJsec.
ForNegativedata40.0+ 25.6
N fJsec.

PROGRAM: PDP-8 DISC SYSTEM EDITOR (DEC-08-ESAA)
The PDP-8 Editor (DEC-08-ESAB) has been modified to operate in
a disc environment. The functions are essentially the same as in
thepapertapeversionwithsome changes to the command set. The
disc version of the Editor is avai lable from the Program Library under
the following code numbers:
Document - DEC-08-ESAA-D
Binary tape - DEC-08-ESAA-PB

II. PDP-7/8

PROGRAM: PDP.-8 DISC SYSTEM DDT (DEC-08-CDDO)
DDT -8 has been considerably modified to operate in a disc environment. The disc version consists of a resident section containing
core swapping and break point logic, plus an essentially invisible
portion containing the search, modify, examine and control logic.
Disc DDT operates as described in the DDT manual for the paper tape
version (Digital-8-4-S}with IJ few exceptions. It is avai lable fror'll
the Program Library under the following code numbers:
Document - DEC-08-CDDO-D
Binary tape - DEC-08-CDDO-PB

PDP-7/9 BASIC PROGRAMMING PROBLEMS

PROGRAtv'I: DDT
PROB LEM: After the user types an I (apostrophe) and before control is transferred to the user1s program, DDT issues a line feed to
the teleprinter. If the user clears the flag and turns on the interrupt before the te leprinter flag appears, an unwanted interrupt
results.

PROGRAtv'I: PDP-8 DISC SYSTEM PIP (DEC-08-PDAA)
PIP (Peripheral Interchange Program) is a general utility program
designed, as the name implies, to transfer fi les between devices,
list directories, and de lete unwanted fi les from either disc or DECtape (with the last two features listed above). The preliminary
version of PIP is available from the Program Library under the following code numbers:
Document - DEC-08-PDAA-D
Binary Tape - DEC-08-PDAA-PB

SOLUTION: A modification has been made to DDT which wi II
avoid the problem by waiting for the flag before transferring control
to the user program. A new version wi II be avai lable from the Program Library late in January.

PDP-9 ADVANCED SOFTHARE PROGRAMMING PROBLEMS

PROGRAM: SYSTEM GENERATOR (SGEN)
The above three programs are the descriptive documents and wi II
be supplied free of charge and without request to users who currently have disc systems.

PROB LEM: lOPS 07 is output about 10 minutes into the generation
due to incorrect. DAT slot assignments.
SOLUTION: The following .DAT slot assignment must be made
correctly:
-10,-14 to OLD system
-J!)to NEW system

REVISED

Example:
($) A DTAO -10, -14/DTAl -15
wi II create a new system on the DECtape on Unit 1 from the existing system on Unit O.

PROGRAtv'I: ODT -8 DEC-08-COCO
The article describing the rewritten ODT which appeared in the
last newsletter (Christmas issue of DECUSCOPE) stated that if the
user places a breakpoint on an instruction which references an
autoindexregister, the autoindex register will not be incremented
when the user requests a "continue". The article suggested that
the user should increment the appropriate register himse If before
requesting the continuation of his program.

PROGRAM: FORTRAN IV
PROBLEM: Error messages are not always output with the lines to
which they apply.

This latest version, ODT-8, DEC-08-COCO, has rearranged the
breakpoint processor to enable it to test for page zero references
and execute them as such. In this version it is no longer necessary for the user to incrementautoindices, ODT -8 wi II handle them
properly.

SOLUTION: The line in error can be either the line printed out
with the error message, or the line immediately preceding it.

This version, as did the previous one, uses essentially the same
command set as DDT -8 but without the All mode.

PROBLEM: The call statement processor does not work correctly
in 16K, 24K and 32K machines.

ODT -8 is avai lable from the Program Library under the following
code numbers:

SOLUTION: Using SYSTEM, make the following patches.

ODT
ODT
ODT
ODT

PROGRAM: FORTRAN IV (DECtape version dated 11/14/67)

(Low core version, origin 1000) DEC-08-COC1-PBi
(High core version, origin 7000) DEC-08-COC2-PB
(source) DEC-08-COCO-PA
(Writeup) DEC-08-COCO-D(L)

Mount the system DECtape on Unit 0, WRITE LOCK.

Load SYSTEM at 17720

3. When the computer halts, set AC switch 0=0, type F and depress CONTINUE.
4. When the computer halts, make the following patch, being
careful to note core size involved.
Core Size

NEW

16K
24K
32K

MA Il~DECS

Address Switches
11141
11141
11141

AC Switches
025420
045420
065420

5. Set AC switch 0=1, type F and depress CONTI NUE. ER wi II
be output to the teleprinter, indicating that SYSTEM is unable to
writeon Unit O. Put Unit 0 on WRITE ENABLE. Type F, and depress CONTINUE. When the computer halts, FORTRAN IV has
been rewritten on the DE Ctape .

MAINDEC-08-D2NA New CR01C Card Reader Test replaces
MAINDEC-08-D201
MAINDEC-08-D6GA NeVi A/D "Calibration Check" replaces
MAl N DEC-845

MACRO Assembler goes back once again to obtain the definition.
This process wi II never cease and for this reason, the usage of the
macro MAC, as given below, will not be properly processed.

PROGRMA.: FORTRAN IV
PROBLEM: There are several major bugs in the current version of
the compi ler. They are:
1.

.DEFIN
MAC, TAG1, TAG2,TAG3
LAC TAGl
SAD TAG2
DAC TAG3
MAC
TAG1, TAG2, TAG3
.ENDM

Hollerith constants do not work.

2. Unary minus is placed before exponentiation in the hierarchy
of events. The use of parenthesis does not always eliminate the
error.

PROGRAM: MACRO-9 MANUAL DEC-9A-AM9A-D and DEC9A-AM9B-D.

Statement functions do not work correctly in all cases.

4. Long involved iterations will occasionally give completely
erroneous results or loss of accuracy.
5.

PROB LEM: An incorrect macro generation is given in Section
3.6.3, page 3-9.

BACKSPACE, REWIND and ENDFI LE do not work.
SOLUTION:

SOLUTION: A new version of the compiler will be issued in the
near future which wi II eliminate these problems.

MACl
TAG1, TAG2, (400,(777, TAG3
should cause the generation of:
LAC
TAGl
TAD
TAG2
MAC2
(400, (777
XOR
(400
AND
(m
DAC
TAG3

PROGRAM: FORTRAN IV and MACRO-9
PROBLEM: The versions of FORTRAN IV and MACRO-9 currently
being shippedwith PDP-9systemswill not allow DEOape input and
output for assemblies or com pi lations in less than 16K systems.
SO LUTI ON: Sma lIer versions of both the Assembler and the Compiler are being prepared and, for your convenience, will be
shipped directly to your installation as soon as they become available. This should occur no later than March 15, 1968.

The line

MAC2

(400, (777 is missing in the manual.

PROGRAM: CONV (DEOape version dated 11/14/67)

PROGRAM: MACRO-9 (DEOape version dated 11/14/67)

PROBLEM: The 7-to-9 Converter lists only to the teleprinter.

PROBLEM: The pseudo-op .END is occasionally not recognized
in programs that contain macro calls which contain no real arguments.

SOLUTION: Using SYSTEM, make the following patches to enable
listing on any device.
1.

Mount the system DECtape on Unit 0, WRITE LOCK.

Load SYSTEM at 17720.

SOLUTION: Using SYSTEM, make the following core patch.
1.

Mount the system DEOape on Unit 0, WRITE LOCK.

Load SYSTEM at 17720.

3. When the computer halts, set AC switch 0=0, type C and depress CONTINUE.
4.

3. When the computer holds, set AC switch 0=0, type M and
depress CONTINUE.

When the computer halts, make the following core patches:

Address Swi tc hes
4.

When the computer halts, make the following core patches:

Address Swi tc hes

12325
12345
12347
12364
12366
12562

AC Switches

13414
13415
13416

157177
557355
613520

AC Switches
002766
000766
002766
000766
002766
002766

,~~

(~
~
5. SetACswitchO=l, type M and depres~QNTINUE. ER will
)
be output to the te leprinter, indicating thaf\~ unable---ro--

5. Set AC switch 0=1, type M and depress CONTI NUE. ER wi II
be output to the te leprinter, indicating that SYSTEM is unable to
writeon Unit O. Put Unit 0 on WRITE ENABLE, type M, and depress CONTINUE. When the computer halts, MACRO-9 has been
rewritten on the DEOape.

write on Unit O. Put Unit 0 on WRITE ENA~pe M, and depress CONTINUE. When the computer halts, the Monitor has been
rewritten on the DECtape.

PROGRAM: MACRO-9

PROGRAM: KEYBOARD MONITOR (version dated 11/14/67)

PROBLEM: Recursive calls within macro definitions initiate an
unending processing of that macro.

PROB LEM: In configuration with API, occasiona IIy a double PIC/
API interrupt wi II occur.

SOLUTION: Recursivecallsshouldnotbeused. (Please reference
the macro definition given be low as an example.)

SOLUTION: Using MONITO, make the following patch to inhibit
these double interrupts.

When a call for the macro MAC is encountered by the Assembler,
it searc hes memory for the defi ni ti on to expand the mac ro . Si nce
there isanothercall for MAC contained within the definition, the

Mount the system DEOape on Unit 0, WRITE LOCK.

Load MONITO at 17720.

in the fie Id.

3. When the cor:nputerhalts, set AC switch 0=0, type M and depress CONTINUE.
4.

1. BLOCK mode will not work correctly if only the BLOCK ON
command is issued. It is necessary to issue a TOP command immediate Iy after the BLOCK ON command.

When the compi ler ha Its, make the fo IIowing patc h.

Address Switches

AC Switches
2. CLOSE NAME wi II not work if the OPEN command contained
a NAME. Issue a CLOSE only and the file will be closed with the
name given in the OPEN command.

000401
740040
220255
600376
200006
705504
400356
620003
140000
120000
760111
200242
620367
060203
440255
620255
040152
750200
705512
740010
500547
040203
240344
060152
240343
741400
060242
600257

151
256
257
260
337
340
341
342
343
344
373
374
375
376

377
400
401
402
403
404
424
425
426
427
430
431
432
433

3. Filesarenotmanipulatedcorrectlyif .DATslot -14is assigned
to DTA1(2-7)and. DATsiot -15 isassigned to DTAO. After closing
thefilewillbeon the scratch device (-15), rather than the input/
output device (-14). This can be avoided by (1) assigning both
-14 and -15 to the same device or (2) using PIP to transfer the file
back to the original tape after the editing process is complete.
4.

SOLUTION: Anewversionofthe Editor will be distributed in the
near future which wi II eliminate these problems.
PROGRAM:

LINKING LOADER

PROB LEM: The error message . LOAD 3 is not listed in the manua I.
SOLUTION: . LOAD 3 indicates a subroutine not found, which
means that the Loader was unable to resolve a global. The name
of the global, with an address field of all zeros, will be output to
indicate what is missing.

C. PROGRAMMING NOTES
PI AND DEVICE HANDLERS

5. SetACswitch 0=1, type M and depress CONTINUE. ER will
beoutputtotheteleprinter, indicating that MONITO is unable to
write on Unit O. Put Unit Oon WRITE ENABLE, type M and depress
CONTINUE. When the computer halts, the Monitor has been rewritten on the DECtape.

Disabling the PI by System Device Handlers
At the present time one device handler on Iy (DECtape) keeps the
Ploffwhile servicing interrupts and three reasons for this are: (1)
the timing between a change from search to read/write is critical
(200 fJsec), (2) as a system device DECtape is so relatively slow
that optimum response time seems desirable. Since interrupts from
other devices can cause timing errors requiring reinitiation of
DECtape I/o, response time could be adverse Iy affected, (3) the
maximum time during which the PI is normally off (97 fJsec) seems
insignificant for all but very special systems. Now, either such
systems should be equipped with API where the critical devices are
placedon API levels higher than DECtape, or the user may easily
a Iter the DECtape service routines if he has on Iy a PI. Be low is a
time summary on the basis of function during which the PI is disabled. (DTDF is assumed to be first in the PI skip chain. 5 fJsec
should be added to PI times for each position be low the first.)

Please note thatthischange will change the typeout of ".IOPS" to

"I".
PROGRAM: MONITOR
PROB LEM: When using the system macro . TIMER, care must be
taken not to do any Monitor calls (CAL), inc luding . TIMER..,in the
subroutine handling the interval interrupt. Since the interval interrupt can occurat al1Y point in the program, it is possible that it
wilioccurwhileanotherMonitorcall (CAL) is being processed. If
a second were then issued, the program would blow up.
SOLUTION: A version of the Monitor wi II be distributed in the
near future which will eliminate the problem.
PROGRAM:

It is not always possible to delete the last line of a file.

PI
67
67
97
*127

KEYBOARD MONITOR

PROB LEM: If a DECtape is used in the system immediate Iy after
having bee" formatted, an . lOPS 14 (directory full) error wi II
occur.

fJsec
fJsec
fJsec
fJsec

API
58 fJsec
581Jsec
88 fJsec
118 fJsec

Function
READ/WRITE complete
Search to Search in same direction
Search to Search, tum around
Parity Error

67 fJsec is taken as both minimum and average given the re lative
frequency of the above functions.

SOLUTION: Before an attempt is made to use the tape, the directory mUft be cleared. This is most easi Iy done by using the N
command in the Monitor or the Z switch in PIP.

PROGRAM; EDIT

Another note should also be made: select, mark track and EOT
during READ/WRITE are considered irrecoverable and an exit to
the Monitor is made, disabling all other I/O. A change would
have to be made ;'1 en V ;ronn'1ents sensitive to such en arrangement.

PROBLEM: The following problems exist in the version currently

*Provided DTEF is placed high in the skip chain at SGEN time.

LINKING LOADER AND BINARY MODES

PDP-9 NEW PROGRAMS

At assembly time, output modes (abso lute/re locatable) shou Id not be
mixed in the same program. The assembler assumes re locatable mode
unti I it encounters a . LOC with an absolute specification. Then
itdeclares the entire program absolute. This can be disasterous at
load time.

DEC-9U-EUMS-PH

MONITO enables patching of the Monitor and skip chail10n the
DECtape version 0 f the advanced software. This program wi II
automatically be shipped to customers with DECtape machines.
DEC-9U-EUSA-PH

Example: If . LOC withan absolute specification is used within the
body (not at the beginning) of a program, the entire program wi' I
be loaded, as though it were absolute binary, with a starting address of O.

DEC-9T -QFBA-PA
The initial mode of the Editor is line-by-line, which is most useful
for a fairly long program which has only a few edits. It is much
faster than operating in BLOCK mode.

FORTST

FOInST is a source program written in FORTRAN IV which is part
ofthe checkout package for the advanced software, both DECtape
and paper tape versions.

Unlike the Basic Editor, there is ~need to issue a READ before
editingcanbegin. It is necessary only to issue one of the locative
requests; FIND, LOCATE or NEXT. NEXTwillaccess the first line
of the file, whileFINDand LOCATEwillaccess the line requested.

PDP-9 NEW MAINDECS (Tapes and write-ups)
MAl NDEC-9A-D1 EA-PH
MAl NDEC-9A-D6GA-PH
MAl NDEC-9A-D6HA-PH
MAl NDEC-9A-D6JA-PH
MAl N DEC-9A-D6KA-PH
MAINDEC-9A-D6LA-PH
MAl N DEC-9A-D6tv\A-PH
MAl NDEC-9A-D6NA-PH
MAl N DEC-9A-D60A-PH
MAINDEC-9A-D6PA-PH
MAl NDEC-9A-D6QA-PH
MAINDEC-9A-D6RA-PH

Theexample following assumes paper tape input. Forpurposesofillustration, the following short program will be the input file.
Necessary chonges are indicated in parenthesis.
C TEST
(Change date)
C 1-28-68
(Incorrect FORMAT statement number)
READ(4, l)X
Y=X
(Should be Y, not X)
WRITE(3, 10)X
10 FORMAT (F6.3)
(No STOP statement)
END

Extended Memory Address Test
A-D Calibration Test
AF040 Diagnostic and Demo
339 PJMP Test
339 POP Test
339 Push Button Test
339 Instruction Test
339 Visual Display
Little Pictures for a 339
VF38 Search Logic Test
339 Character Generator Test
342 Character Generator Type in
Progr<;~m

The underlined characters are those typed by the user; the others
are responses made by the Editor.

PDP-9 REVISED MAINDECS (Tapes and write-ups)

EDITOR

MAINDEC-9A-DOHB-PH
MAIN DEC-9A-D1 CC-PH
MAl N DEC-9A-D1 DB-PH
MAINDEC-9A-D2FB-PH
MAINDEC-9A-D6AB-PH
MAl N DEC-9A-D7 AB-PH

>LLi.

1-28-68
>C /1-28/2-2 J.
2-2-68
:;,Nd

.,.IT-

READ (4, l)X
>C /1/10 ~
READ (4, 10)X
>L WJ.
WRITE (3, 10)X
,)C /X/Y ~
WRITE (3,10)Y
10
J..10

C;YSTEM

System enables patching of all DEC supplied system piogioms, eX~
c luding DDT and the Linking Loader, on the DECtape version of
theadvancedsoftware. This program wi II automatically be shipped
to customers with DECtape machines.

USING THE EDITOR IN L1NE-BY-UNE MODE

MONITO

EAE Part 2 Test
Extend Memory Control Test
Parity Option Test
CR01E Card Reader
Display 34H, 30D, 370
Basic Exerciser

PDP-9 DOCUMENTATION
DEC-9A-AM9B-D

MAC RO-9 Manua I

This manual is a revision of the MACRO-9 Manual and includes
corrections and some additions. It is not a major rewrite of the
manual.

J..

DEC-9A-C7 AA-D

FORMAT (F6. 3)

P DP-9 Advanced Software Checkout
Package

This write-up is a concise checkout test of the PDP-9 advanced
software for both the paper tape and DECtape versions. It makes
use of three tapes in addition to the advanced software: FORTST
(DEC-9T -QFBA-PA), CANRUN7 (DEC-9T -QCAA-PA) and CANRUN9 (DEC-9T-QMAA-PA).

INPUT

>~STOPJ..
~

EDIT
)CLOSE ~
EDITOR

DEC-9A-AF40-DN

Supplement #1 to FORTRAN IV:
Advanced 8K DECtape Systems Software

Announcement of the small version of FORTRAN IV.

D. NEW AND REVISED SOFTWARE

DEC-9A-AM9A-DN

PDP-7 REVISIONS
DEC-07-CDDA-PM
DEC-07-CDDA-LA

DDT
DDT Listing

Supplement #1 to MACRO-9:
Advanced 8K DECtape Systems Software

Announcement of the sma II version of MACRO-9.
23

IMPORTANT
PLEASE DIRECT ALL REQUESTS FOR LIBRARY MATERIAL MENTIONED IN THE DIGITAL SOFTWARE NEWS
SECTION TO THE DEC PROGRAM LIBRARY, iN THE PAST, MANY OF THESE REQUESTS HAVE BEEN SENT
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WHICH SHOULD BE USED FOR REQUESTING DtC PROGRAMS, IHESE FORMS ARE SUPPLIED WITH E8CH
SHIPMENT OF DEC SOFTWARE, AND ADDITIONAL COPIES MAY BE OBTAINED BY CONTACTING THE DEC
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DEC PROGRAM LIBRARY
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24

Pin',(-Or~gin.a

tor r S Copy

CONTENTS

MEASUREMENT OF SPONTANEOUS MORPHOLOGIC
VARIATIONS IN THE ELECTROCARDIOGRAPHIC P-WAVE*
Melvin D. Woolsey, Daniel A. Brody,
and Robert C. Arzbaecher
Division of Cardiovascu lar Diseases
College of Medicine
University of Tennessee
Memphis, Tennessee

PAGE
Appl ication Note:
Measurement of Spontaneous Morphologic
Variation in the Eiectrocardiographic r-'yVave

Acknowledgment . . . . . . . . . . . . . . . . . .

Programming Notes
Single Instruction Operation of PDP-8
FORTRAN (4K) . . . . . . . . . .
Note from C. S. I. R. 0., Austral ia

6
6,7

Note from DEC Re: PDP-9 Skip on Flag.

Note from Defence Research Telecommunications

FOCAL Points and FOCAL Abstracts

Software for Sa Ie

Letters . . . . .

11, 12

Module Users News.

LAP6-1 C . . . . . .

13, 14

New DECUS Members

15-19

ABSTRACT
A real-time computer-oriented data acquisition and analysis
system is described for measuring the spontaneous morphologi c
variations in the electrocardiographic P-wave. A wavefol1T1
index is obtained by comparing each P-wave on a beat-by-beat
basiswithareference P-wave. Agraphic history of the P-wave
morphology is produced by plotting th is waveform ,index versus
time. When structural changes in the P-wave are present the
waveform index is further used to separate the P-waves into
families and these families are averaged.
INTRODUCTION
During a recent investigation of the high-fidelity atrial electrocardiogram we observed and reported 1 1

The number

in the 9,th array.

is the number associated with the kth node

Rules for computing these numbers wi II be

given shortly.
One noti ces that every node has a sol id and a dashed line

General

drawn to it from two nodes in the previous array.
will now be used in computing the numbers

The Discrete Fourier Transform (DFT) of a set of N equally-

N-1

where W=e

-~TIi

and i=

from node A and that the dashed I ine comes from node B in the

X Wik

previous array.

The collection SO' Sl' . . . ,

associated with B; that is,

The sol id I ine denotes a

multiplication process, whereas the dashed line indicates

It would seem that computation of the complete spectrum
2
{SJ would require N complex multiplications. But if N
I
is an integer power of 2, then an algorithm developed by

addition.

Thus, in Figure 1 the number associated with the

second node (k = 2) in the first array (9,= 1), (k is written in
binary) is given by:

Cooley and Tukeyl called the Fast Fourier Transform (FFT)

enables computation of the spectrum with only N log 2 N

(11-1)

X(l 0) = X(l 0) W + X(OO)

Th is important development can reduce
because this node contains a 2 inside, indicating that the

computation time by as much as 99 percent. The purpose of

solid line comes from node 10 in array 0 and that the dashed

this paper is to present and verify that algorithm as well as

line eminates from the node 00.

to explain its implementation.
II.

is formed as follows: Take the number
c
associated with A and mu Itiply by W . Add this to the number

SN_1 is called the frequency spectrum of the data set {Xi}.

complex mu Itiples.

associated

with the various nodes. Call the number in the kth node of
th
the 9, array C. Suppose the solid line is drawn to that node

spaced time samples X ' Xl . . . , X - is defined as:
O
N l

S·=L
I
k=O

These lines

The number within the kth node of the 9,th array is formed by

The FFT Algorithm

the following process: Write k as a binary number of '0 bits.
No reasons will be given for the validity of the algorithm;
however, a set of ru les wi II be presented in this section.

Sca Ie that number ('0 - 9,) places to the right, fi II ing the new Iy
It

vacated bit positions with zeroes.

is hoped that the reader will blindly accept them until they

the bits (or invert the bits).

are verified in the next section.

and 9,=3.

Suppose there are N time samples to be transformed and that
N is an integer power of 2; that is, N=2'O.

In binary form k=0110.

bits makes the number in the 6

array of N nodes and associate sample Xo with the first node

Scaling this'O -9,=1

Reversing the order of the
rd
node of the 3 array 1100 =

12.

(which will be labeled 0), Xl with the second node (which

Let the binary representation of k be:

(11-2)

will be labeled 1), and so on (see Figure 1). Call this verO
ti cal array X , so that the sample X is associated with the
k
kth node of XO. Remember that k runs from 0 to N-l; k will
be expressed as a binary number.

For example, let '0=4, k=6,

places to the right gives 0011.

Draw a vertical

Then reverse the order of

where each k. is a bit of value 0 or 1. Then the procedure

Now draw in '0 other such

for locating

vertical arrays of N nodes to the right of XO. Label the
l
O
verti cal array immediate Iy to the right of X by X and the
1
one to the right of X as X2 and so on to x'O

t~e solid and dashed arrows of the

kth node in

the 9,th array is as follows: The solid line to the kth node
.
th
.
st
In the 9,
array comes from the node In the 9,- 1 array whose
address is the same as k's except bit k

'0-9,

is set to 1. The

dashed Iine stems from the node in the 9, - 1st array whose

Just as in Figure 1, each node or circle in the drawing has
a number within it.

address is the same but bit k 9, must be O. For example,
'0 nd
take the second node (k = 10) in the 2
(9,= 2) array. Here

* After September, 1968, 813 Yale Station, New Haven,
Conn ect i cut.

'0-9,=2-2=0.

Now k=k1kO=10.

Setting kO=l gives 11 so

the sol id I ine comes from node 11 in array 1.

Putting kO = 0
(111-1 )

results in 10. Thus, the dashed line comes from node 10, as
shown in Figure 1 .
The Fourier Transforms are given by the numbers associated
with the rightmost array X a, in bit inverted order.

For

example:

(11-3)

is the column vector consisting of the N data samples.
1
To express x P in terms of XP- , take
(111-2)

By using the above ru les, a tree-graph for any N = 2'0 inputs
can be drawn. The numbers associated with the nodes in the

cP for

and solve for

first array are caleu lated from the inputs by using the arrows.

each p, giving a recursion formula

which wi II enable computation of x'O (the transforms) from

The numbers of the second array are ca leu lated from those of

X (the samples).

the first, and so on, until the numbers associated with the
last array are known. These are then unscrambled by bit

Define R.Q,(j) to be j shifte~ .Q, places right with %IS filling in

inversion and are the Fourier Transforms. The tree-graph

the vacated positions and
~

i to

be bit inverted j.

Denote

.,J

for N=8 is shown in Figure 2.

[R.Q,(j)J by R.Q,(j).

Notice in Figures 1 and 2 that there is always one pair of

Consider

nodes in each array which has solid and dashed arrows coming

.,
..
p th array. IW rltmg
I In terms

X~,

the number associated with the jth node in the
0

f'Its b'It structure:

(111-3)

from the same nodes in the previous array. Also observe
that the difference of t~e numbers held within each pair of
nodes is always N/2.
00 and 01 of array 2.

X~OO)

Th€ algorithm gives

For example, in Figure 1 look at nodes
Both have dashed arrows com ing from

and sol id arrows from

X~01)'

(111-4)

p
p- 1
X. =X.
I
1'0-1'"

.
0(.. ,,'
+ W 'O-p
I ~p-1 ?I'O-p-1 10

And the difference be-

tween the numbers in the nodes is 2-0=2=4/2=N/2.

where the 1 and % replace the bit j'l!

Because

operators Z
. N
Wi +y =

wlwY

u-p

.
.
= Wi [COS1T - j SIN1TJ =-W l

X~OO)

and

X,
' , . '1 . ~f "'10
Ic'-l . "I'O-p+ 1 I ~ij

. Define the two

and I so that
n

(111-5)

and

only half the number of multiplications are actually needed.
To illustrate this, consider the node pair

(j) p- 1

(111-6)

X~01)'

From the graph in Figure 1,
2

X(OO) = X(OO) + X(Ol)

2
1
1
X(Ol) = X(OO) + X(Ol)

(11-4)

1
1
= X(OO) - X(Ol)

In this notation

(111-7)

From (111-2) and the definition of matrix multiplication
N-l
1
(111-8)
X~=L C~ XPI k=O
Ik k

Because

where C~k are the components of matrix CP , From (111-7) and

III. Proof of Val idity

(111-8) these components are given by:
Matrix algebra provides a convenient way to verify the FFT
algorithm.

if k=1 p (j).

If x P represents the pth vertical array of nodes

(p runs from % to a

then x P can be represented as a column

vector by:

C =1
jk

if k=Z (j)
p

Cfk=%

in all other cases

(111-9)

for each p= 1, 2, ... ,

Specifically for j=O and j=o-l,

By the recursion formu la (II 1-2)

(111-15) gives
(111-16)

and

(111-10)

By the definition of matrix multiplication extended to 0 matrices,
th
o-k.
Denote by Zl Z2 Z 3 14 (j) the composition of operators

element of K C

the pq

IIIlk~O C'-kJ

(111-11)

Zl (Z2(Z3(14(j)))) and let this definition include any number
and permutation of the operators Z. and I..

and (111-16) the set of N

From (111-15)

recursion formu las becomes:

pq
or

1 1 ... I 2Z 1Z (p) etc. through all permutations
1 2
0- 00

of operators I and Z.

p and q (= 9, o and.Q,O) are fixed.

where 9,1' 9,2' ... , 9,0-1 are dummy indices running from 0

L IT.C

0- j
I .Q,'Y .9,'Y . 1
u -I u -1That means their bit patterns

But for each term

to N-1. Make the following identifications,:
(111-12)
9, 0 ~ p,

are also fixed.

Note that each element of the operator string

Z. or I. sets the 0- jth bit of p to 0 or 1, but that each operaI
I
tor in the string has a different value of j, and hence affects

(111-13)

a different bit of p. The j=ooperator affects bit 0 and the
j=l operator affects bit 0-1 of p.
From (111-10) and the definition of matrix multiplication

affects all bits of p independently.

(111-14)
N-1
XO=L
9, 0 9, =0

N-1

'6-1

0-1

j=O

U
-

This means that the value

... Oo(p) is independent of p itself: p is a dummy
2
here. (I use 0. to represent the jth operator. 0. could be
I
I
Z. or I. .) Because q is fixed, then, so is the operator string.
I
I
In fact, defining
(111-17)

"f'

>II C
9,1'···9,

of q=Ol

So the operator string

.Q,0-j.Q,0-j-1

°q.

(111-14) is of the form of a discrete Fourier Transformation so

=Z'Y . if q.=O
U -I
I
I

it is reasonable to proceed by calculating the coefficients
and

°q.

=1 . if q.=l
0-1
I

IT .CI

the operator string

0_'

I
is not to vanish (and all
.Q,0-j.Q,0-j-1
vanishing terms contribute nothing to the summation) then
'6-'
each term C I
in the multiplication must not vanish.
.Q, . .Q, . 1
0-1 01According to (111-9) this means that either
Now, if a term

°°
1

, .. 00 is just

Therefore
q=O
~-1

(111-15)

° ... °
0

qo-2

(111-18)
(p)

and there is only 1 permutation of operators 0. for which the
l
o j
term
C does not vanish. From (III-18) the
I
9a
j-l

-fo -

recursion formu la (111-15) becomes

(111-19)

Now

L.
I

} (111-23)
).q.
I

In accordance with the defin it ion in (111-17), (111-19) says:
j
Co =1
£o-j£o-i- 1
co- j
£'0- j£'O- j-1

Because W =1

when

(111-20)

q.=O
I

It is easi Iy seen that
(111-24)

=wRj(£'O-j) when q.=l
I
(111-24) can be verified by carrying out the product

(111-20) can be written as
,.,
-WR.(-\, .).q.
I u -I
I

",-i
U

(q'O-l·· ·qO)(PO·· ·Po-1) according to the rules of binary

(111-21)

multiplication and then excluding all bits whose positions

£'0- j £'0- j- 1
are higher than '0-1.
It wi II be shown that the expression R.(Q,,,, .) is the same as
I u-I
R.(£ ). Now
I '0

(III-23) into (111-14)
N-l
x'O =Lw{pq) mod NXO
p
Because

Denote by B the jth bit of £'0 (=4) after the operator 0
qj
qj
has been appl ied.

q=O

W= e (-21Ti/ N) , ·t·
I IS

N-l

X
p

1
2
j
£ '0 - £'0 - ... 9a B
B
... B
'0
'0
q. 1 q. 2
qo
11-

Substituting

are unaffected by 0

b·
th a t
VIOUS

q;o-

(111-26)

XOW pq
q

p for

p in (III-26) and using the fact that p=p
N-l
(111-27)
x't=LxOwpq
p
q=O
q

... 0
qj-1

Hence

The algorithm says that the pth transform is the number associated with the

T.I C '0 i

Since the terms

~-i~ -j-1

term,

p node of the
p

N-1
S =LXOw
p q=O q

algorithm, is the same as (1-1), the definition of the DFT.

j=O

Hence the verification is complete.

L. denote the operation of shifting left by

I
places, with zeroes fi II ing in the vacated positions.

IV.

It is

Implementation of the Algorithm

This section presents and describes in detail a flow chart

apparent that

(111-29)
pq

One observes that (III-29), the result of application of the

W R.{~).q.
I
I

Let the operator

(1I1-28)

Combining (111-28) and (111-27) gives

(111-22)

last array, or

S =X~

do not vanish only for a

particular £1' £2' ... , £'0 -1 the summation is reduced to one

Hence

Therefore (III- 25) becomes

_ '0-1 '0-2
j
£ .- £ . £ .... £
.B
B
... B
'0-1 '0-1 '0-1
'0-1 qj-1 qj-2
qo

(111-25)

w{pq) mod N=W

since bits '0-1 to j of

Thus putting (111-24) into (111-23) and

(the basis for much of this flow chart is a Lincoln Lab Technical
4
Memorandum by Charles Rader ) for computation of the FFT
of a set of N time samples.
'0-1

An actual program, written in

PDP-8 FOCAL *, as we II as several sample outputs, are 1 isted.

=TI
j=O

Use of the flow chart (Figure 3) enables transformation of any

* Trademark
6

of Digital Equipment Corporation

exactly the spacing between mirror nodes.

N = 2 v points in place. This means that the only major
storage requirement consists of the initial data vector.

H is made to be

H+ 1, so its value is -(v- L) when the Lth array is being bui It.

The

great reduction in dynamic storage area is accomplished by

Finally, P is N-1, pointing to the last item of the current

operating on two nodes at a time-two nodes whose arrows

array.

stem from the same pair of nodes in the previous array.

In box 7, C is initialized to 1.

Referring to Figures 1 and 2, it is seen that the spacing be-

L
tween two such nodes in array L is always N/(2 ).

how many mirror node pairs have currentiy been handled.

Also,
The basic arithmetic is dealt with in box 8.

the difference between the numbers in any two such nodes

to the Kth power and multiplied by the number associated with
K
the pth node, X . Note that W can either be calculated
p
on the spot or stored ir a look-up table for speed. Because

each node and its mirror image in pairs eliminates the need
for additional storage space.
There are several symbols pecu Iiar to the flow chart that

5 gives the spacing between mirror nodes, it follows that piS

need explanation. A function R V appears in boxes 8 and 15.

mirror Q is located at P-5.

This denotes the operation of bit reversing the v bit binary

Hence, Q is set to P-5.

Addition

and subtraction operations are then carried out as specified

A "squiggly" bracket, } , enclosing severa I

by the algorithm and the mirror nodes in the old array are

operations means that those operations are to be carr ied out
simu Itaneously.

Lines 1 and 2

scale P V-L places right and bit invert the result, getting K,
N
the number within the pth node. W(=e -2rr i/ ) is then raised

is always N/2. 50 every node has a "mirror" node which is
L
which is found by spacing up N/2 in the array. Taking

number Q.

C is a counter which indicates

replaced by thier counterparts in the array being produced.

Finally, the square brackets in the first

line of box 8 denote taking the integer part.

Referring to Figures 1 and 2, one observes that we can

Now to a de-

proceed linearly up the array in the manner of box 8 up to a

tai led explanation of the chart.

certain point.
Box 1 consists of initial ization.

N is the number of samples

and v the power of 2 to which N corresponds.

the images of previously encountered nodes.

L gives the

number of the array currently be ing constructed.

From this point on we wou Id be working with

region must be skipped over.

5 is an

Hence, this

5ince the spacing of mirror

nodes is 5, it follows that such special points will occur

index which gives the spacing between mirror nodes in each
1
array. It is initial ized to N/2 = N/2. H is the number

every 5 nodes.

In order to stop Ii near increase in P (box 9)

at such points, C is incremented (box 11) on each cycle

-(v-L) and is initialized to -(v-1)=1-v.

through box 8. When C=5 (box 10) a special point has been

Boxes 2, 3, and 4 generate the first array from the data

encountered. 50 it is imperative to space past the" dangerous"

vector.

area by setting P to P-5 (box 13).

The reason for computing the first array apart from

However, before this is

the other arrays is that it requires no multiplications (examine

done we must check to see if we are at the top of the array,

Figures 1 and 2 and observe that the nodes in the first array

less we pioneer into regions which do net exist (box 12).

contain only 0 and N/2) , hence saving computation time.

P+1 =5 then we are within one "dangerous" region of the top

Q, the index of the array, was initialized to one below the

of the current array and are done.

middle node so that we move from the middle of the array to

before by spacing up 5 in the array. The loop, of course, is

the top, adding or subtracting mirrors as specified by the
N 2
algorithm (W / =_l).

term inated by box 5.

When this is done, box 5 checks to see if the calculation is

are performed on complex numbers.

complete.

parts must undergo the indicated operations.

If not, we continue as

One must keep in mind that all operations in the flow chart

If it is, the resu Its are reshuffled into proper order

by bit inversion. This is done by boxes 15 through 19.

50 both real and complex

A program using the algorithm in Figure 3 has been written

the computation is not over, we move on to the next array.

in PDP-8 FOCAL.

A listing and some examples are given in

Here the crux of the algorithm comes-L becomes L+ 1, sig-

Figures 4 and 5.

nalling the construction of the next array.

language which, as the length of the program demonstrates,

5/2.

lends itself quite well to the FFT algorithm.

Also, 5 becomes
L
Note that on the Lth time through 5 is just N/2 ,

FOCAL itself is an on-line conversational

The bit inversion

operation is accompl ished by a PDP-8 machine language
subroutine, shown in Figure 6.
function FNEW (

References

FOCAL has a special user

1. Brigham, E. 0., and Morrow, R. E., "The Fast Fourier
Transform," IEEE Spectrum, pp. 63-70, December, 1967.

) which enables the user to define a

function simply by writing the machine language code to
perform the desired operation.

2. Cooley, J. W., and Tukey, J. W., "An Algorithm for
the Machine Calculation of Complex Fourier Series," Math
of Computers, Vol. 19, pp. 297-301, Apri I, 1965.

Here FNEW (NU, U) treats

U as a binary number of NU bits and then inverts it.

When

the program text is abbreviated according to the ru les of the

3. Gentlemen, W. M., and Sande, G., "Fast Fourier
Transform for Fun and Profit/' Proceedings of AFIPS 1966
Fall Joint Computer Conference, Vol. 29, pp. 563-578.

FOCAL language, the program will transform up to 32 points
in 4K of memory. Since the FOCAL program is of value

4. Rader, Charles M., Lincoln Lab. (M.I.T.) Technical
Memorandum No. 62L-0075, October, 1965.

mostly for demonstration and verification purposes, a machine
language version is currently being developed by the author.

c.,

5. Singleton, Richard
"On Computing the Fast Fourier
Transform," Commun-ications of the ACM, Vol. 10, No. 10,
pp. 647-654, October, 1967~---

This will transform up to 2048 real points in 4K of memory in
under 5 seconds.

6. "What is the Fast Fourier Transform?" IEEE Transactions
on Audio and Electroacoustics, Vol. AU15, No.2, pp .4555, June,1967.

Figure 1 .

Tree-graph for FFT for N = 4

Figure 2.

x 3 (000'

, Sc

3
X (001)

, S4

X 3(010)

'52

x3(Ol1)

, S6

3
X (lCO)

'5,

Tree-graph for FFT for N=8

3
x (,Qi) , 55

x2(1i 1\

X 3 ":'

x 3 ;{,q.

ENTER

LO\l2 N + U
1+L
1/2 N .... S
1/2N-1 ..... Q

1-l)+H

xQ+~+xQ-xQ

}

XO-X~+!!2 .... XO+.'i2J

L+11i2 S H +1N- 1 _

L
S
H

8
[PX2H] .... U
Rv {U) ..... K

l
19

wK xp .... G

p-s .... Q
G+xQ .... XP}
XQ-G ..... xQ

DONE

Figure 3.

Flowchart for calculation of the Fast Fourier Transform

*C- TRANSFORM OF SINE vJAVE OF At'1PLITUDE 1.0

**C-

TRANSFORM OF COSINE WAVE OF Af'.1PLITUDE
*GO
WHAT POHER OF 2 PO INTS ARS TO BE
TRANSFORMED?:3
INPIJT THOSE POINTS.

*GO
t.-!HAT POt'JER OF 2 PO I NTS ARS TO BE
TRANSFORMED?: 3
INPUT THOSE PO I NTS

:.707
:1

:.707

: -.707

: - • 707
:-1
: -.707

: -1

: - • 707

:0
:.707

FOURIER TRANSFORMS
RE~L PART
IMAGINARY PART

0.00
0.00

0.00
-1 .00

0.00 .

0.00

0.00
0.00

0.00
(il.00

Figure 4A:

FOURIER TRANSFORMS
REAL PART- IMAGINARY PART

FREQUENCY (CPS)
D",C.

0.00
1.00
0.00
0.00
0.00

1
2
3
4

0.00
0.00
·0.00
0.00
0.00

Figure 48

Ecamples of FFT Using FOCAL
9

TRANSFORM OF INTEFERE~CE PATTE~N FORMSD BY MIXING A SINE
WAVE OF AMPLITUDE 1.~ AND A COSINE WAVE OF AMPLITUDE 1.5

!:.fHc\'T POt"ER OF :? POINTS ARE TO BE TRANSFORMED?:3
INPUT THOSE POINTS.

FOU~IER TRANSFORMS
REAL PART IMAGINARY PART

:1•5

:t .76R
:t

0.0(7)
1 .5(7)

: - .353

0.~0

0.00
-1 .0-0
0.0'1

~.00

0.(7)(7)

0.QlVl

0.00

: -1 .5
:-1.768
: -1
:. J

Figure 4C

53
01.06
01.08
01.10
01.18
01.20
01.22
01.24
01.26
01.28
01.32
01.34
01.36
01.38
01.40
01.42
01.46
01.48
01.50
01.52
01.54

ERASE
ASK "WHAT 'POWER OF 2 POINTS ARE TO BE TRANSFORMED?""NU,,!
SET N=2tNU; SET TPN=2*3.14159/N; FOR I=0"N-l; SET XICI)=0
SET S=N/2; SET L=I; SET Q=S-I; SET H=I-NU
TYPE "INPUT THOSE POINTS.",,!; FOR I=0"N-l; ASK XRCI),,!
SET SR=XRCQ+S)+XRCQ); SET XRCQ+S)=XRCQ)-XRCQ+S);SET XRCQ)=SR
IF CQ) 1.26,,1.26; SET Q=Q-l; GOTO 1.22
If CL-NU) 1.28,1.54,1.28
S~T L=L+l; SET S=S/2; SET H=H+l; SET P=N-l; SET Z=I/C2tC-H»
SET C=1
SET U=fITRCP*Z); SET K=fNEWCNU"U)
SET COS=fCOSCTPN*K); SET SN=FSINCTPN*K)
SET GR=COS*XRCP)+SN*XICP); SET GI=COS*XICP)-SN*XRCP)
SET Q=P-S; SET SR=GR+XRCQ); SET SI=GI+XICQ);SET XRCQ)=XRCQ)-GR
SET XICQ)=XICQ)-GI; SET XRCP)=SR; SET XICP)=SI
SET P=P-l; If CC-S) 1.48,,1.50,1.48
SET C=C+l; GOTO 1.34
If CP-S+l) 1.52,1.26,,1.52
SET P=P-S; GOTO 1.32
DO 3; QUIT

03010 TYPE !,"fOURIER TRANSFORMS"" !,"REAL PART IMAGINARY PART",!!
0)3.20 fOR I=0"N-l;SET K=fNEWCNU,I>JTYPE %3.2,XRCK)/N,"
",XICK)/N.!
Figure 5:. Listing of FOCAL Program

ITHIS ROUTINE INVERTS THE BIT ORDER Of THE "NU"
IBIT WORD "U""WHERE NU AND U ARE THE ARGUMENTS Of
IK=FNEW CNU, U).
*27
fLIP-l
*fNTABf+15
fLIP

IBOTTOM
IPUT NEW FUNCTION ON TABLE

*4550
JMS I INTEGER
TAD fLAC+l
CIA
DCA CNTR
SPNOR
GETC
PUSHJ
EVAL
INTEGER
JMS
DCA K
fLLOOP, TAD U
CLL RAR
DCA U
TAD K
RAL
DCA K
ISZ CNTR
JMP fLLOOP
TAD K
DCA fLAC+l
JMS I fLOAT
JMP I EfUN3I

fLIP,

FLOAT,
CNTR,

5355

If IX fLOATING AC CfAC)
IflRST ARGUMENT CNU)

IDEf I NIT I.Ot-JS

INUMBER Of BITS
IMOVE PAST SPACES
IGET PAST COMMA
IEVALUATE SECOND ARGUMENT CU)
If IX FAC
IBUILD UP RESULT IN K
ITRANSPOSE U ABOUT ITS CENTER
IBY ROTATING U RIGHT AND K LEfT.
IBIT TO BE TRANSPOSED IN LINK.
IINSERT INTO LOW ORDER BIT Of K.
If OR ALL NU BITS.
IPUT RESULT IN FLAC+l AND fLOAT

IDONE.
Figure 6:

Bit Inversion Subroutine for FOCAL

(i'I

GETC=4514
PUSHJ=4507
EVAL=1602
INTEGER=52
fLAC=44
FNTABf=374
K=fLAC+2
U=fLAC+l
EfUN3I=106
SPNOR=4527
$

TECHNICAL SYMPOSIUM

DECUS FALL 1968 SYMPOSIUM

"APPLICATIONS OF SEA-GOING COMPUTERS"
January 13- 14, 1969
La Jolla, Californ ia

A "Ca II for Papers II has recently been sent out on the Fa II 1968
DECUS Symposium. The symposium, schedu led for December
12 and 13 at the Jack Tar Hotel in San Francisco, will follow
directly behind the FJCC (December 9-11). Arrangements
have been made to allow DECUS members planning on attending
both meetings to register at the Jack Tar for the whole period.
Special hotel registration cards for this purpose wiii be sent
to DECUS members shortly.

Sponsored by
San Diego Section of the Marine Technology Society
and
MTS Data Engineering Committee, Western Group

If Yot! are planning on presenting a paper, participating in a

A technical symposium on "Applications of Sea-Going Computers II wi II be co-sponsored by Scripps Institution of Oceanography and the Marine Technology Society at Scripps I campus
in January, 1969.

workshup'~r

panel discussion, please return your participation
questionnaire attached to the "Call for Papers II as soon as possible.
Session themes - Data Acquisition and Control, Interactive
Systems, Education, Biomedicine, PDP-8, PDP-9, PDP-lO,
and Modu les/Hardware worksJqops have already attracted several interesting papers.

Dr. William A. Nierenberg, Director of Scripps, is General
Chairman. In his words, 'The conference will concern itself
with the use of sea-Hoing computers, which enable scientists
to record data more easi Iy and to understand the data at sea
rather than to wait for the larer, delayed processing of data
on shore. II The program wi II review experiences to date with
sea-going data processing system .. and wi II exam ine the potent~al for computing machinery in mil itary and scientific marine
appl i cations.

For more deta ils contact the Executi~e Secretary, DECUS Office, Maynard, Massachusetts 01754, Khone: 617,897-5111,
Ext. 414 or 447

CECUS ELECTIONS
Executive Co-chairmen are Dr. John Mudie of SCrippS and
Charles Jackson, Chairman of MTS Data Engineering Committee, Western Group.

This is not only the year of the "elephant" and t'he' "donkey",
but alsoit's time again for reelection of DECUSofficers. Thi's
year it's t he offices of Equipment Chairman, Publications
Chairman, and Programming Chairman.

The program will consist of four daytime sessions andone evening panel. The subject area is a sequel to the ONR-NSIA
"Symposium on Automatic Collection, Processing and Analysis
of Oceanographic Data II held at Scripps in December, 1964.
Attendance is open to all interested scientists and engineers.
Invitations are also being extended to selected foreign
scientists.

Nom i nat ions to date for these oHi ces are:
Equipment Chairman - Sypko Andreae, Lawrence Radiation
Laboratory, Berke ley, Cal iforn ia
Publ ications Chairman - George Cooper, Logic, Inc., Detroit,
Michigan
Programming Chairman - Michael S. Wolfberg, Moore School
of Electrical Engineering, University of Pennsylvania, Philadelphia, Pennsylvania

Authors interested in presenting papers at the conference should
submit the title and an abstract of not more than 500 words by
September 30, 1968, to:

Additional nominations will be accepted up to October 1. All
nominations must be supported by three DECUS members.
(DECUS Bylaws, Article IV, Section E, 2 d.)

Dr. John Mudie
Applications of Sea-Going Computers
Scripps Institution of Oceanography
P. O. Box 109
La Jolla, Cal iforn ia 920Z7

The official list of candidates will appear in the next issue of
DECUSCOPE, and ballots wi II be sent out in early October.

DECUS PROGRAM LIBRARY NOTES
NEW PROGRAMS

Contributors whose topics are selected for presentation at the
symposium wi II be notified by November 15. All manuscripts
are due by December 31, 1968. All papers accepted will be
published in a special issue of theMTS Journal Q£ Ocean Tech~. General information concerning the symposium can
be obta ined from:

All new programs accepted since the publ i cation of the June
1968 Library Catalog wi II be announced in the next issue of
DECUSCOPE.

Mr. Charles B. Jackson
MTS Data Engineering Committee
P.O. Box 2158
La JolJa, California 92037

RE:

DECUS Programs Nos. 5-13,8-123,8-124, and 8-125

Due to reproduction costs invo Ived in completing the numerous
requests for card decks for the above listed programs, there

It is interesting to note that this program actually includes two
subroutines. First, in Part 1, the maximum of the set of integers must be found. In Part 2, the actual LCM computation
takes place.

will be a service charge of £10 for each card deck requested.
Anyone requesting one of these programs shou Id send a purchase
order ora check made payable to Digital Equipment Corporation
to the DECUS Office. All checks shou Id be accompanied by
a library material request form.

This program wou Id probably find its greatest use in classrooms
of the lower grades. It cou Id be a tremendous aid to the
teaching of fractions.

PROGRAMMING NOTES
- - - - FOCAL POINTS - - - -

Base to Base Integer Conversion - The FOCAL Base to Base
Conversion routine will convert any positive integer less than
2048 from one base system to another. Such a program would
find use in the teaching of high school mathematics where such
problems in numbertheory are encountered. The program does
not handle fractions, and it does not check the input number
to be sure that all of the digits are allowed in the specified
base. Readers are invited to write a more universal conversion
routine.

FOCAL POINTS was inaugurated in DECUSCOPE, Vol. 7,
No.2. The purpose of this column is to serve as a forum of
comments and/or programs written in DEC's new fami ly-of-8
conversational language, FOCAL. These programs and examples will be kept in printed form only and will usually be
distributed in groups. Ex isting categories are Engineering,
Plotting, Mathematics, Education, and Accounting. Other
group headings wi II no doubt be added rapidly. Anyone desiring
a setor sets of these write-ups should write the DECUS Office,
Maynard, Massachusetts 01754, indicating the category desired. Abstracts of additional routines follow. Each program
submitted either to an existing category or as a new category
should be submitted with a listing, an example of execution,
and a brief abstract which wi II be printed in this column. We
may also reproduce some results of their operation.

Prime Number Generator - The Prime Number Generator is a
program which will accpet a number, N, and type out all
primes less than that value. As soon as the program is fin ished,
it loops back and starts over again by asking for N.
One use for this program would be found in computer-aided
instruction in the lower grades where primes are first encountered.

This column will serve to disseminate information about modifications to the FOCAL system for special applications. However, the FOCAL program itselfand its documentation will be
distributed from the DEC program library.
Mathemat i cs
Submitted by:

Repeating Decimal Program - This routine computes the decimal
equivalent to any rational number whose absolute value is less
than 1. Such a program wou Id be very usefu I in the teaching
of fractions in school. Readers are invited to investigate computations with fractions greater than 1 .

DEC Applications Group

Square Matrix Mu Itiply - The arduous task of mu Itiplying two
square matrices is quickly done by this FOCAL Matrix Multiplication routine. The user inputs" N" indicating the number
of rows and columns each matrix wi II have. The computer then
requests input of the elements of the two matrices. The result
of the multipl ication is typed out in an understandable matrixlike format.

Subm itted by: R. E. McCu IIough, University of Colorado
Notable characteristics of this program are:
a.
It is expressed in on Iy five Iines of FOCAL script so that
it loads qu i ck Iy.

N-th Degree Polynomial Data Point Fitting Routine - This
program accepts the x- and y- coordinates for an unlimited
number of data points and calcu lates for the equation

b. It will process matrices of varying dimensions. Size of
each matrix is lim ited on Iy by memory capacity. (In 4K FOCAL
the Iimit is about 6 rows and columns.)

the coefficients AN which best fit the equation to the data
points. The fitting criterion is " least squares. II The program
allows the user to select the degree, N, of the fitting equation. N may be as large as 7 .

c. Because it inputs and outputs the matrix va lues in a matrixlike format, input transcription errors are less likely to occur.
. The readers are invited to investigate the general ization of
this algorithm to extend it to the processing of rectangular
matrices.

N-th Degree Polynomial Data Point Fitting Routine, with RMS
Error - This program is the same as N-th Degree Polynomial
Fitting Routine except that it calculates the RMS error between
the y-coordinates of the data points and the evaluated fitting
equation. It will accept only a limited number of data points
and the maximum equation degree allowed is inversely related
to th is number.

Least Common Mu·ltiple (LCM) - The LCM routine is a neat,
short program which will compute the LCM of any number of
positive integers. Input is in two stages. First, the number
"N" of integers is requested. This is followed by the input of
the i ntege rs .
12

Engineering

FAST LOGARITHMIC CONVERSION
FOR
DISPLAY OF NUCLEAR DATA

Second Order Differential Eguation - This is a routine to solve

2
D X _ K1

. g~

+ K2 . X = ~ given K1, K2, and initial values

C. A. Burke and H. W. Lefevre
Physics Department
University of Oregon
Eugene I Oregon

DT
DX
D2X
for X, DT' and -2-' The user also selects the time interval
DT
DT. The resu It is plotted on the TTY from time zero unti I
interrupted.

The following subroutine for generating a logarithm and seal ing
it for a ten-bit display results from a comment by Professor
Robert Brochers of the University of Wisconsin-liThe obvious
way to make a fast logarithmic display is to make it linear
between binades."

A check is made for off-scale values.
Accounting

LOGCAL is written for a PDP-7 with extended arithmetic. It
'generates a characteristic by finding the most significant bit
and tacking on the six next most significant bits for use in lieu
of a true mantissa. As listed below the routine plots numbers,
22 or less on the base line and plots 2 18 _1 at full scale on a
ten bit display. The maximum deviation from the true logarithm
is less than 1% of fu II scale with sixteen binades on scale.
There is, of course, no error for any number with a zero mantissa.

Subm itted by: G. L. Helgeson, Helgeson Nuclear Servi ces,
Inc.
Payroll Calcu lations - This routine is used to calculate payrolls.
It is based on the Ca Iiforn ia State Un~mployment Insurance rate
of one percent of the gross salary, FICA rate of 4.4 percent
of the gross salary, and withholding tax as given in Table 7
on page 21 of Circular E, Publication No. 15 (Rev. May,
1968) of the U.S. Internal Revenue Service.

The subroutine is entered with the number to be converted in
the accumu lator and returns with the logarithm properly sea led
for an immediate DYL.

To use it one identifies the individual by typing his name and
social security number with the Teletype on II LOCAL. II Then,
switching to " LI NEil and starting the program, one types a II 111
if the individual is single or 11211 if he is married. Next, one
enters the number of exemptions, then the number of pay periods
per year. This is followed by en'tering the base pay and any
prem ium pay. After th is the computer does the rest.

LOGCAL,

~
SPA!CLL
JMP .+11
CLQ! NORM-25
RTL
LMQ
LACS
SNAtCMA
SKP!CLA
LLS 6
JMP I LOGCAL
LRS 13
TAD (l6~~
JMP I LOGCAL

This program cou Id be modified easi Iy to fit the ru les of any
particular state. If some of the pay ranges would not be used,
they cou Id be om itted from the two tables, making more room
for other routines, such as providing running totals on gross
pay, deductions, and net pay.

L1NC AND L1NC-8 DELEGATES
(Continued from Page 24)
Dr. Alvin M. Revzin
Federal Aviation Administration

PDP-B FORTRAN TRICKS

Dr. John M. Rhodes
University of New Mexico

J. Harvey
Communications and Systems, Inc.
Paramus, New Jersey

Dr. Robert H. Schiffman
University of Missouri
Dr. Robert J. Shofer
Albert Einstein College of Medicine

Type A Format Data

Garth Thomas
Ohio State Un iversity Hospital

The basic PDP-8 FORTRAN (DEC-08-AFAC) does not allow
alphabetic input data. It is possible to read alphabetic text
into a format statement with text between quotes, but this has
two shortcomings: the input text must be the exact number of
characters provided between the format statement quotes, and
the FORTRAN program cannot access the characters fortesting,
sorting, etc.

James H. Utzerath
Marquette University School of Medicine
C. C. Wilton-Davies
Royal Naval Physiological Laboratory
England

Avery simple machine language patch has been found that lets
the program load characters into integer variables as 8-bit
numbers. It uses the numbered PAUSE to call short subroutines,

Dr. James Winkelman
Bio-Science Laboratories
13

which in turn call input/output routines in the FORTRAN Operating System itse If. The subroutines in the operating system
perform the basic functions usually needed:

6; CONTINUE
C; Now generate all characters and print
Ci Start with a Be II
NCHAR = 135
D07J=l,113
PAUSE 3958
NCHAR = NCHAR + 1
7; CONTINUE
STOP
END

1.
Input/Output device determined by switch register setup
as for the usual FORTRAN operations.
2.
3.

Ignoring of blank tape and I ine feeds on input.
Echoing characters to the Teletype for low-speed input.

4. Automatically appending line feeds to carriage returns on
input or output.
5. On input, return ing carriage returns not I ine feeds to the
ca II i ng programs.
In PAL, the machine patches needed for the operating system
of August 15, 1965 (08-AFC3), are:
INPUT, ~
JMS I 134
DCA NCHAR
JMP I INPUT
OUTPUT, ~
TAD NCHAR
JMS I 153
JMP I OUTPUT

/READ A CHARACTER
/ A FORTRAN VARIABLE

Direct Access to the DECtape Buffer

/OUTPUT A CHARACTER

The FORTRAN DECtape faci Iity of the OS-AFAC version uses
a physi cal READ or WRITE statement to move 128 word blocks
of data between tape and core. A pseudo READ or WRITE
moves it in or out of the FORTRAN variables. In some cases,
such as reading data from the block, altering it and writing
it backonthe tape, a physical reread of theblock is necessary
in order to reset the pointer and allow writing at the buffer
beginning. Several lines of coding are required this way.
Also, the space lost to the DECtape buffer is sometimes needed.
If the buffer could be treated as a FORTRAN array and accessed
directly with assignment statements, a considerable space
saving and increase in flexibility results. This can be done
by using negative subscripts in an array variable.

Of course, using K. I. Gordon's technique (Letters, Vol. 6,
No.3, of DECUSC OPE) these simple PAL routines can be
coded entirely in FORTRAN. The following must be the first
part of your FORTRAN:
NCHAR = NCHAR
DIMENSION 10(8)
10(6) = -17~~
10(7) = 179~
10(8) = -1,03~
10(2) = 766
10(3) = -1685
10(4) = -1~34

The DECtape buffer starts at 5600. Using symbol print to locate an array in the program, an offset can be calculated that
will result in the subscript actually pointing to the DECtape
buffer. Since the operating system does not check the lega I ity
of subscript va lues, this subterfuge works. Any array of the
proper type can be used, of course, including one containing
active data, since the array name is simply a foundation for
the negative subscript. However, for an example a special
one word array is declared:

On execution of a PAUSE 3962, a single character will be
read from the keyboard (or high-speed reader if SR selected)
and left in the FORTRAN variable NCHAR. On execution
of a PAUSE 3958, the right hand 8 bits of the number in
NCHAR are sent to the Teletype or punch. A trivia I example
follows:

DIMENSION KBUF (1)
NOFF = -1~22
READ 8, 9, l~
KBUF (3 + NOFF) = 1 + KBUF (3 + NOFF)
WRITE 8, 9, 1~
STOP
l~i FORMAT (I)
END

DIMENSION LETR (2~~)
DO 3 K = 1, 2,0~
PAUSE 3962

Cj A character is in NCHAR. Test it for

Ci Control - form feed which is 140 decimal
LETR (K) = NCHAR

IF (NCHAR - 14~) 3,5,3
3; CONTINUE

Ci Found a form feed or end of buffer
Ci Now print buffer
5i K = K-1

Element 1 of array KBUF is at 7576 octal and the variable
NOFF is set to the negative offset required to point to the tape
buffer. Then block 9 of unit 8 is read, the third word in the
block incremented by 1 and the block rewritten on un it 8.

DO 6 J = 1, K
NCHAR = LETR(J)
C; A character moved from array to NCHAR
C; will be printed by PAUSE 3958
PAUSE 3958

The value of NOFF wi II
used. For a one-word
probably -340 (warning:
operations so the offset
14

be different if floating point words are
floating array at 7574, the offset is
this writer has not tested floating point
val ue is suspect).

BINARY PUNCH [Digital-B-S-U Syml
MODIFIED FOR LlNC-B

*4111

LlNC
JMP 170 5370

*4170
Glen W. Johnson
Institute of Oceanography
Dal housie Un iversity
Halifax, Nova Scotia
CANADA

TAD C15
ISSP
TAD M3
ION
ICON
NOP

The usefulness of this program can be greatly increased by including it on tape to be read in automatically by the LOAD
switch. Furthermore, there is no need for two halts to get the
starting and last addresses. By changing the two locations
noted below, both switch registers will be used and only one
halt made.

M3,

-3

C15,

1377
6165
1376
6001
6141
7000
7775
0015

/SH LlNC "P" REGISTER
/12 IN ACCUMULATOR
/ST ART LI NC AT 1115"

To make these modifications, perform the following steps from
the LI NC console.
Change

Location

7476
7477
7500

from

7604 (LAS)

6145 (lLES)

7402 (HLT)

7000 (NOP)

1.
2.

LOAD
DO: 0700

0002

Check that locations 21, 22, 24, 26, and 175 are zero. The
last one is in a PROGOFOP patch to define OPR Oand OPR 1.
Check other patches for program flags which must be zero.
If there are no changes to be made, skip step 3.
3.
4.

The program usage shou Id now be changed by replacing sections 4.4.3 and 4-.4.4 in the write-up with the following:

DO: 0704
DO: 0700

0002
0000

Insert the above commands, dropping the leading 4 from the
addresses (i.e., insert 5370 in L1NC address 111, etc.).

4.4.3
The computer will halt. Set the initial address
of the block to be punched in the left switches and the final
address in the right switches Press CONTINUE.

DO: 0704

0000

Note that now there will be only one halt before each consecutive block is punched.
To put the modified BI N PUNCH on tape, follow these steps:
1.
2.
3.

L1NC-8 EVENT COUNTER

Raise LOAD.
Using the BI N LOADER, read in the BI N PUNCH.
Make the above changes from the LI NC console; i. e.,

Up to 256 events can be counted and indicated for the operaforls peace of mind while a long program is running. OPR 2
is defined to increment bits 0 to 6 of the PDP-8 accumulator
and the Iink each time the command is given. OPR i 2 resets
these bits to zero.

in location 3476 put 6145, and
in location 3500 put 7000.

DO: WRC (0704)

7/006.

This program assumes that my previous patch to define OPR 0
and OPR 1 is in PROGOFOP. The origin has been set at 2020
to allow the use of bank 1 as a lower memory bank with least
interference. Locations requ ired are 25 10J but this cou Id be
reduced to 1510 by doing without the link bit (count 128
events) .

L1NC-8 LOAD PROGRAM MODIFICATIONS
The following changes to the LOAD program (DEC-L8- L2AA-D)
cause LAP6-3L (DEC configuration) to be read in and started
by lifting the LOAD switch. As in the original LOAD, the
user may insert his own read commands. If one desires to use
the PDP-8 RIM or BIN loaders, there is ample time to press
STOP before block 200 is reached.

*15
RCG
7/200

0701
7200

It is suggested that the program be placed on block 7 of tape
and the following patch be placed in the LOAD program on
blockO.

/L1 NC COMMANDS TO START
LAP6-3L
/DEPENDS ON CONFIGURATION USED
/PDP-8 COMMANDS TO START

*4071

/Iocation 71 in block 0
JMS
7
2000

I READ IT

4713
0007
2000

/BN
/initial address for block

ILINc-B EVENT COUNTER

LINSTR=31
*125

*2020
INCRMT,

RESET,

ACCIM,
LIM,
C12,
G40,
C20,

IDISPATCH LOCATION TN PATCH V.JHICH DEFINES OPR 0 AND 1

INCRMT

2020

TAD LINSTR
AND C20
SZA CLA
JMP RESET
TAD LIM
RAR
CLA
TAD I ACCIM
TAD C40
DCA I ACCIM
RAL
DCA Ln~
TAD LIJ.1
RAR
JMP I 176
TAD C12
DCA I ACCIM
CLL
DCA LIM
JMP I 176

1031
0250
7640
5237
1245
7010
7200
1644
1247
3644
7004
3245
1245
7010
5576
1246
3644
7100
3245
5576
0362
0000
0012
0040
0020

362

12
40
20

II = 1 ?
lYES, RESET COUNT =
INO, COUNT MORE
IRECALL L BIT

/RECALL REST OF COTJNT
IINCREMENT
/SAVE L BIT
IRESET L BIT
ILOCATION WHICH CONTAINS GOBACK=1460
lIN PROGOFOP PATCH

changes listed below will allow eif"her version of FOCAL to
reference theTypeAFOlA Multiplexer and Analog-to-Digital
Converter withthe FADCfunction. The argument isthemultiplexer channel number in decimal. The value converted has
only 11 bits accuracy because of the manner in which the number is handled in the floating accumulator by FOCAL.

CHANGES TO FOCAL WHICH ALLOW REFERENCING
THE AF01 A MULTIPLEXER AND A-D CONVERTER
WITH FADC FUNCTION
Robert E. McCu Iiough
University of Colorado
Boulder, Colorado
The latest version of DEC's FOCAL program (DEC-08-AJAB)
and the original version are both written to reference the Type
189 Ana log-to- Digita I Converter with the function FADC. The

3203
3204
5753
5754
5755
5756
5757
5760
5761
5762
5763
5764
5765
5766
5767
5770

5604
5753
4452
7300
1045
6002
6542
7300
6531
5361
6534
7004
7032
6001
5770
3214

JMP I 3204
5753
JMS I 0052
CLL CLA
TAD 0045
IOF
ADSC
CLL CLA
ADSF
JMP. -1
ADRB
RAL
CML RTR
ION
JMP I 5770
3214

The values generated are from 0.0 to 0.999512 for input voltages of 0 to -10 volts.

IFLOATING TO FIXED CONVERTER

IFIX WHICH GIVES 0000 FOR
IZERO VOLTS, 37778 FO~ -10 VOLTS

in the main data program in the order in which he anticipates
their occurrence. The answers are stored in a buffer in the
subroutine which is then stored on tape.

A PRE-ANSWERING OPTION FOR LlNC-B
QUESTION AND ANSWERING
SUBROUTINES
Wa Iter H. Jesteadt
Bioacoustics Laboratory
Eye and Ear Hospital
Pittsburgh, Pennsylvania

The main data program uses a sense switch option at every
point where the Q&A subroutine would normally be read in
from LI NCtape to decide whether the Automatic Control subroutine shouid be read into quarter two instead. instead of
displaying the text specified in the main program, Automatic
Control searches for the question mark codes surrounded by
76 1 s and fills these locations sequentially with answers from
the list supplied by the user. It returns to the main program
after the text.

Extensive use of the standard Question and Answer subroutine
in LI NC or LlNC-8 data processing programs maximizes flexibility and minimizes the possibility for errors on the part of
inexperienced users. The major disadvantage of such a conversational mode is that it requires the continued presence of
the userto carryon the conversation, whichmaybe interrupted
by long periods of printing resu Its or reading paper tape data.

The exact sequence of instructions required in the main program
and for initialization will depend on the nature of the main
program itself. Only the listing for the sequential filling of
question marks is presented here. It should be noted that the
index register cannot be used anywhere in the main program
and that the Automatic Control subroutine must be stored again
on tape before anything else can be read into quarter two.

Use of an alternate Q&A subroutine, called Automatic Control, makes it possible for an experienced user of the program
to answer all the questions in advance. In an initial ization
procedure, the Automatic Control subroutine is read in from
LI NCtape and the user is asked to type answers to the Q&Ns

1000
1001
1002
1003
1004
1005
1006
1007
1010
1011
1012
1013
1014
1015
1016
1017
1020
1021
1022
1023
1024
1025
1026
1027
1030
1031
1032
1033
1034
1035

0001
0002
0003
0004
0005
0006
0007
0010
0011
0012
0013
0014
0015
0016
0017
0020
0021
0022
0023
0024
0025
0026
0027
0030
0031
0032
0033
0034
0035
0036
0037
0040
0041
0042

[AUTOMATIC
[CONTROL
[SUBROUTINE
81000
LDA
0
BCL i
6000
STC 2
#71 LDH i 2
SHD i
7600
JMP 4E
5HD i
7700
JMP 5E
JMP 71
#4E .LDH i 10
5TH i 2
LDH i 2
SHD i
7600
JMP 71
LDH i 10
5TH 2
J~IP P-6
#5E LDA
2
BCL i
6000
ADA .i
6001
STC 6E
#6E 0000

1000
0000
1560
6000
4002
1322
1420
7600
7015
1420
7700
7026
7005
1330
1362
1322
1420
7600
7005
1330
1342
7017
1000
0002
1560
6000
1120
6001
5035
0000
17

/SET 2 AS POINTER TO
/TEXT IN MAIN PROGRAM
/FILL NEXT LOC. FROM LIST

/10 POINTS TO LIST

/CLEAR HALF WORD BIT
/ADD JMP CODE AND
/INCREMENT
/RETURN TO MAIN PROGRAM

SOROBAN CARD READER PDP-9 INTERFACE

BINARY PUNCH
William Simon
University of Rochester Medical Center
Rochester, New York

Norman Benowitz
Data Systems Division
Hughes Aircraft Company
Culver City, California

Programs for SNAP, the real-time interactive language announced in Medical & Biological Engineering, January, 1968,
are now available for the solution of up to 14 simultaneous
linear equations and for multicompartmental analysis of up to
4 decaying compartments.

An interface between the Soroban Model ERD Card Reader and
the PDP-9 has been designed and is operational at Hughes
Aircraft Company. Data from the 1100 card-per-minute reader
may be transferred through the data channe lor to the AC under
program control. Use of the data channel allows 80 columns
of card data to be placed in consecutive memory locations with
a single lOT instruction and eliminates the need for II ready"
testing of each column of data. Fewer than 80 columns may
be transferred from a card by an appropriate setting of the
PDP-9word count. Data maybe read in binary form or translated to BCD (Hollerith) code by interface hardware. Illegal
BCD punches are detected by the interface, and a bit is set
in the word transferred to indicate this.

SNAP, developed at Harvard Medical School for PDP-8, allows
up to 90 real-time, interpretive instructions and up to 200
tabu lor entries. The usual arithmetic, trigonometri c, and
lograithmi c functions ore avai lable. S NAP is compact and
easy to learn. For example, a real-time pulse interval histogram can be written in 11 instructions. Typically, beginners
with less than 20 minutes of instruction are able to plot functional relationships such as circles, parabolas, and sinusoids.
SNAP has been used primarily in a wide variety of biological
problems, but is equallysuited to manyof the problems of engineering and physics which can be done on PDP-8 computers.

Card reader status may be tested by reading an 18-bit status
word. An 10RS bit and several skip lOT instructions may also
be used to determ ine card reader status. The interface connects the card reader to API and PI. Interrupts include:

Two slightly modified versions of SNAP-ANASNAP and
SNAPT-are available from the University of RochesterMedica I Center, New York. Both of these use most of the same
instructions as SNAP, with the addition, in the case of
ANASNAP, of a set of instructions which allow the PDP-8 to
simu late an analog computer. The equ iva lent of an analog
integration is performed by a single instruction incorporating
automatic time scal ing, and up to 12 curves may be displayed
by a single instruction. S NAPT (page turn ing S NAP) allows
180 instructions at the cost of deleting some arithmetic functions.

a.
b.

the cord reader is ready to read the next card,
the word count has reached 0 (indicating the
desired number of columns have been transferred), and
t roub Ie ex ists in card reader hardware.

The card reader interrupts may be individually enabled or disabled in any combination with a single lOT instruction. An
lOT instruction allows cards to be offset in the stacker for
visual identification. Use of all Soroban features and signals
and several additional features is obtained through a versati Ie
interface with 14 principle lOT instructions, plus many microcoded combinations.

SNAP, ANASNAP, and SNAPT programs are completely editable in core via the Teletype. No paper tape handl ing is
involved, but programs may be stored on paper tape if desired.
S NAP is avai lable from DECUS for PDP-8 I s with and without
EAE (DECUS No. 8-122), and in a sl ightly abridged version
for LI NC-8 I s (DECUS No. L-31).

The interface is constructed with DEC R & W Series modu les.
Fifty-five modules are required.
Software in use and available with the interface includes a
PDP-9 Advanced Software System monitor-compatible card
reader handler. A version of MACRO-9 allows assembly directly from punched cards.

RESTART METHOD/PDP-9

NEW DECUS PUBLICATIONS
DECUS Program library Catalog - June 1968

William Broadley
Learning Research and Development Center
University of Pittsburgh
Pittsburgh, Pennsylvania

Second Canadian Symposium Proceedings - he Id at the Skyl ine
Hotel, Ottawa, Ontario, Canada, February, 1968
1968 Spring Symposium Proceedings - symposium held at the
Bellevue Stratford Hotel, Philadelphia, April, 1968

We have been using a method of restarting our 8K paper tape
system on our 16K PDP-9 that is simpler than using a system
restart program. If the computer has halted, we type a control P, then we start at location 1. An lOPS error will usually
occur, but a second contro I P and a second start at location 1
will usually restart the curr;nt system program. We find this
sequence especia lIy usefu I after power up occurs.

1968 DECUS Brochure - description of DECUS, objectives,
activities, etc.

employed to write and read tape. Being fu II duplex allows
writing and reading on the same unit (read after write) or on
different un its (source, output). Data can be transferred
asynchron.:>usly up to 600 characters/sec., and many of the
existing Teletype routines can be used directly.

LOW-COST MAG TAPE SYSTEM-DATAVOICE 8

J. B. Brown
Betatech, Inc.
Bedford, Massachusetts
Betatech has developed and is offering a low-cost magnetic
tape system for the PDP-8 series of computers. The system
consists of interface eiectronics constructed from DEC FiipChips and up to four tape decks of the high quality audio type
using standard 1/4" tapes. Software with the system includes
a relocatable selective dump routine and a load-and-go loader.
Presently under development is a set of routines to provide an
operating system compatable with Symbolic Tape Editor, PAL
III, etc. In addition to recording digital data, the system
I)rovi des a voice channe I in para Ilel with the data. Operating
. instructions, program and data identification are conveniently
recorded on t his channel and often eliminate the need of
bringi ng and referring to bu Iky documentation.

Software
The software included with the system at the present is a relocatable selective dump and a load-and-go loader compatible
with the BIN LOADER. An operating system employing the
tape system is under development but is a sub ject of a later
DECUS arti cle.
For further information contact: J. B. Brown, Betatech, Inc.,.
Box 345, Bedford, Massachusetts 01730, AC617, 275-0750.

The DV-8 system has been specifically designed to assist in
operations where the main I/o device isthe standard Teletype.
When storage or input-output requirements are high or the
computer is bei ng shared among many users, the high transfer
rate of the DV-8 is a wei comed addition to the installation.
The enti re DEC software for the PDP-8 can be stored on a single
tape reel and left mounted ready for immediate recall. Snapshots of crashes and system reloades are quickly performed.
Each user can easi Iy keep his enti re set of programs (two mill ion
characters) on his private tape reel and save partially debugged programs for the next session.

OIGITAL WRITE
"ENABLE PUSH BUTTON

AUDIO RECORD
J;'USH BUTTON

FOOTAGE. COUNTER

POWER O!\l;OFF AUDIO
PLAY LEVEL CONTROL

MODE SElECTOR

AUDIO RECORD
LEVEL CONTROL

FAST WIND SLIDE

O-NTlN-~

b. OFF-LINE REVERSE ENABLE
c. OFF·L1NE FORWARD ENABLE
d. LOAD ENABLE

Hardware
The hardware supplied consists of interface electronics and one
of several types of audio tape transports. Below is shown a
reel-to-reel unit with the manual controls called out. This
unit contains three heads on each of two tracks (erase, record,
read). The audio track operates in the conventional manner,
while a phase modulation type of recording is employed on the
data track. At the operating speed of 7 1/2 cps, both channels
have a bandwi dth of 15 kHz. The record and recovery scheme
used on the data track, however, requires only a 4 kHz bandwidth to insure proper performance in a less-than-perfect environment. Both under program control and manually, the
tape can be moved in either direction at the operating speed
of 7 1/2 cps. Manua I contro Is a lIow fast forward and fast reverse.

MODULE USERS GROUP MEMBERS
Ralph Bish
Space Radiation Effects Laboratory
Philip Owen Dufty
University of Western Australia
Western Austra Iia
Dr. Terry E. Ewart
University of Washington

The interface electronics provide a single lOT to control the
operation of a tape unit. Each unit, independently, can be
commanded to go forward or reverse, read and/or write. In
addition, a program-selectable 60 cps interrupt can be enabled
to provide accurate motion control timing.

Ian George Nicholls
Un iversity of Western Austral ia
Western Austra Iia
Gunther Reith, Ph.D.
Lehigh Va Iley Electroni CSt Inc.

To control dataflow, the electronics associated with theTeletype unit is shared with the tape interface. During tape operation, the Teletype printer/punch is held marking, and the
keyboard/reader is logically disconnected. After a tape operation, the program returns the Teletype unit to its normal
function.

Dr. Herman H. Samson
Arizona State Un iversity
Ron Southworth
U. S. Plywood

While transferring data to the tape system, the tape unit
appears identical to the operation of the Teletype with the
exception of transfer speed. Thus the lOT's and interrupts
associated with the printer/punch and keyboard/reader are

D. R. Thorne
Arizona State Un iversity

LEITERS
II Dear Mrs. Cossette:

II Dear Mrs. Cossette:

Please refer to my letter of Apri I 1, 1968. (Ed. note: Published in DECUSCOPE, Vol. 7, No.2.) I really didn't intend
to send you an April fools joke, however, that's the way the
program turned out to be. If the last four instructions are deleted and left as they originally were, the modified Phoenix
assembler will compile all the teletype keyboard reader mnemon i cs. I am sorry for the error. The correct changes are:

II We at Lamont Geological Observatory are very interested in
obtaining Calcomp Plotter software for our PDP-8. We wou Id
appreciate it if you could send us any information on available
DEC or DECUS software.

ADDRESS

OLD CONTENT

We wou Id a Iso I ike to correspond with anyone else interested
in the development of plotter subroutines along lines similar
to those of the IBM 1130/1800 plotter subroutines.

NEW CONTENT
Sincerely,

0200
1465
1467

6032
6031
6036

6016
6011
6016

Herbert Poppell
Lamont Geological Observatory of Columbia University
Palisades, New York 10964

Very truly yours,
HELGESON NUCLEAR SERVICES, INC.

II Dea r Mrs. Cossette:

Geo. Lewis He Igeson
President ll
872 Abb i e Street
Pleasanton, California

II This is to draw attention to a small" bug" in the LI NC-8 LIBRARY system. This is in the binary papertape loader segment,
which is called into core memory following the command
ESCAPEor when anyuser program is called. Thebugis that, if
the binary loader encounters an origin setting which is not followed by any data before the next origin setting, then the location corresponding to the first origin setting is cleared to zero.
This is of practical importance because PAL III punches an assumed origin at location 200 at the head of every tape it outputs,
whether or not thesymbolictape specifies anything at location
200. Thus, if the loader is used to read in, e.g., binary subroutines for a FORTRAN program, the main program will be
corrupted due to the loss of the contents of register 200.

94566

DECUS,

III am planning to work on a SNOBOL4-lnterpreter for the
PDP-8.
III would like to know whether someone:
. has worked on it;
or
. is working on it;
or
. is plann ing to work on it.
Andre M. Gagnoud
C IDS Pro ject
3625 Wa Inut Street
University of Pennsylvania ll
Philadelphia, Pennsylvania

"I have not attempted to cure the bug by altering the loader
program (which is obviously tight for space); it would also, I
think, be difficult to suppress the initial origin 200 punch by
PAL Illi probably the easiest" fix," once one is aware of the
trouble, is to make a habit of always assigning location 200
appropriately on every binary tape to be used in conjunction
with Library. In the case of FORTRAN subroutines, this requires

19104

*200
SKP CLA

II Dear Mrs. Cossette:
Yours sincerely,

III would like to thank Messrs Griffin of Ontario Hydro and
Gordon of DEC for their comments on my note on negative
input level conversion published in DECUSCOPE, Vol. 7,
No.1.

G. R. Herveyll
The School of Medicine
Un iversity of Leeds
Leeds, England

II I agree with their comments entirely. In my note I, in fact,
tried to point out a general method for level conversion. Perhaps I should not have used DEC modules as an example.

WANTED
Yours faithfully,
Information regarding the existence of a PDP-9 Assembler whi ch
will produce object code for the PDP-8.

R. Krishna
Department of Electrical Engineering"
University of Saskatchewan
Saskatoon, Saskatchewan, Canada

Please send detai Is to the DECUS Office.
20

NEW DECUS MEMBERS
PDP-5 DELEGATES
Edward O. Adams
Harvey A!umina V.!., !nc.
Virgin Islands

Kenneth M. Batinovi ch
Sea-Space Systems, Inc.
Trevor .A.. Beard
Texas Instruments, Ltd.
England

(Miss) Vivienne I. Bu rton
The Broken Hi II Proprietary
Company, Ltd.
Austral ia

R. G. T. Bennett
University of Canterbury
New Zealand

Terence Meehan
Brookhaven Nationa I Laboratory

William H. Blaisdell
Eastman Kodak Company

J. F. Petersack
Esso Research and Engineering Company

Dr. John F. Blount
Hoffman- La Roche, Inc.

PDP-7 DELEGATES

A. A. Brodie
Buckmaster and Moore
England

(Miss) Pauline M. Erskine
N.G.T.E.
England
Prof. Eugene D. Homer
New York Un iversity
William C. Maguire
Princeton University
Ewald Teichert
A.S.T. T.
South Afri ca

PDP-8 DELEGATES
William D. Allen
Federal Electric Corporation
Dr. John J. Anta I
Army Materials and Mechanics
Research Center
E. T. Astley
Crosfield Electron ics, Ltd.
England

M. K. Bruce
Ti Ilotson and Son, Ltd.
England
Douglas E. Burgess
University College
England
Daniel H. Cornwall
Foxboro Company
John F. Dille III
The Elkhart Truth

Stanley C. Hanna
Northern and Central Gas
Corporation, Ltd.
Canada
H. J. Hansen
Falconbridge Nikkelverk AjS
Norway
Dr. W. H. Highleyman
Sombers Associates, Inc.
J. A. Hopkins
British Columbia Institute of Technology
Canada
Dr. Bernard Foster Hoskins
University of Melbourne
Austral ia
G. K. Hryciw
Rile/s Data Share International, Ltd.
Canada
Wi II iam L. Jackson
Army Map Service
Dick Jason
Composition Systems, Inc.
Edward S. Johnson
University of North Carolina
Ken Johnson
The Daily Sentinel

J. Elliot
British Aircraft Corporation, Ltd.
England

J. A. Jones
Mobil Oil Company

Adrian B. Ettl inger
CBS Television Network

N. S. Kendrick, Jr.
Georgia Institute of Technology

Don M. Evans
Lawrence Radiation Laboratory
University of California, Berkeley

Wi Ifrid L. Lord
Argonne Nationa I Laboratory

David S. Flower
University of Michigan

Walter J. Bankes
Nuclear Effects Directorate
White Sands Missi Ie Range

Len Fons
General Electric Company

Dale Barbour
Naval Underwater Weapons Station

Ronald W. Gibson
Boeing Company

Cesar Baray
Computer Industries

Louis W. Gilman
Computer Industries

W. Barker
Yorkshire Post Newspapers, Ltd.
England

Richard Granato
Ai rborne Instruments Laboratory

Paul Mackie
Georgia Institute of Technology
Bernard E. Martin
University of Pittsburgh
Gerald Masek
Presbyterian-St. Lukes Hospital
T. J. McAvoy
University of Massachusetts
Manley L. McCorkle
Pan American.,petroleum Corporation

PDP-8 DELEGATES (Continued)
O. D. Mcilroy
Springfie Id Newspapers, Inc.
George Moore, Ph. D.
University of Southern California
Dr. Karl Munkelt
Deutsches Hydrographisches Institut
Germany
Rona Id V. Munro
Computer Industries, Inc.
Dr. David A. Neal
Indiana University Medical Center
(Mrs.) V. D. Needleman
Strand Hote I, Ltd.
England
R. J. Novak
Un iversity of Massachusetts
P. S. Pontin
Assoc iated Sem i condu ctors, Ltd.
England
John J. Reisig
Instrumentation Computer Division
HQ, ISG, USACDCEC
P. E. Sawyer
Bath Un iversity of Technology
England
Prof. Dr. Heinz Schmidtke
Institut fur Ergonom ie
Germany
Dr. H.M.M. Shearer
University of Durham
England
M.H.L. Simens
British Eagle International
Air! ines, Ltd.
England
Festus W. Snodgrass, Jr.
Oak Ridge National Laboratory
Shiyohei Taketomi
Matsushita Commun i cation
Indust.rial Company, Ltd.
Japan
Dr. John J. Uhran, Jr.
University of Notre Dame
Michael G. Vaughan
Comsat Earth Station

R. D. Werner
Atom i c Energy of Canada, Ltd.
Canada

Alton P. Jensen
Georgia Institute of Technology
A. W. Klibbe
Bell Telephone Laboratories

PDP-S/I DELEGATES
Robert G. Ba! la
Pennsylvania State University

PD Dr. med. Helmut Kunkel
Un ivers itats- Nervenk Iin ik
Germany

David L. Brown
Beta Instrument Corporation

Harold Levy
Science and Engineering, Inc.

George L. Brown
Sunderland Technical College
England

Bertrand Lisee
Un iversite de Sherbrooke
Canada

James R. Crane, Jr.
Pilot Metal Fabricators, Inc.

D. G. Lougheed
Leigh Instruments, Ltd.
Canada

Allen L. Cudworth
Liberty Mutua I Research Center
C. C. Cunningham
Western Electric Company, Inc.
Orval L. Davis
Dow Chemical Company
Phillip N. Dean
Los Alamos Scientific Laboratory
Ri chard L. Diddams
Motorola Semiconductor Products
Division
Dr. Joseph M. Edelman
Baton Rouge, Louisiana
Dr. Sam H. Eletr
Institut de Magneto-Chim ie
France
Dr. Jay A. Glasel
Columbia University
Geoffrey D. Green
Western Electric Company
John R. Griffin
Tektronix, Inc.

E. W. Mazerall
University of Manitoba
Canada
Dr. Harris Ripps
New York University Medical Center
Howard A. Rubin
Illinois Institute of Technology
William F. Russell, Jr.
Teradyne, Inc.
Frank H. Sharp
University of Louisville
Dr. James G. Smith
Pennsalt Chemicals Corporation
David A. Starr
Intek Corporation
Lambertus J. Streppe I
Sheen Laboratories
Western Australia
K. M. Wa Iiuzzaman
University of Toronto
Canada

John C. Gwinn
Computer Curriculum Corporatio~

K. B. Webster
Australian Paper Manufacturers, Ltd.
Australia

Randall A. Hale
Transitron

Richard A. Ze itl in
Bellevue Hospital

David R. Hill
University of Calgary
Canada

PDP-sis DELEGATES

Dr. Joseph Jaffe
New York State Psychiatric Institute

H. J. Ward III
Noller Control Systems, Inc.

Peter D. Ager
University of Alberta
Canada
Jean Bohrod
Berkeley Scientific Laboratories

PDP-8/s DELEGATES (Continued)
Ludw ig J. Besse
Schwe iz. Institut fur Nuklearforschung
Switzerland
J. D. Bourland
Baylor University College of Medicine

Frank H. Inderwiesen
Martin-Marietta Corporation
Dr. Arnold H. Kadish
Cedars Sinai Medical Center

James J. Ryan
College of Fisheries, Navigation,
Marine Engineering and Electronics
Canada
Alan J. Rylance
Ti Ilotsons Newspapers, Ltd.
England

S. Karnial
IAEC, NRCN
Israel

J. B. Brad Iey
Algonqu in College Technica I Centre
Canada
Allan R. Bush
Latter-day Saints Hospital
C. R. Conkling, Jr.
Infotec, Inc.

Ear! Ke! Iner
Un iversity of Ca Iiforn ia at Riverside

Tosiya Saito
NHK (Japan Broadcasting Corporation)
Japan

E. C. Jennings
Ministry of Defence
England

F. R. Sanger
International Data Highways, Ltd.
England

Knut Larsen
Drammens Glassverk
Norway

L. W. Shinn
Tracor, Inc.

Als
Charles A. Contarino
Raytheon Company
Dr. P. J. Claringbold
C.S.!'R.O.
Austral ia
Lu igino Conti
S.G.S. Fairchild
Italy
(Mrs.) Yuma Deackoff
Science and Engineering, Inc.
Adrian Demayo
Department of Energy, Mines
and Resources
Canada
Cha Ires H. Drummond
Owens-Illinois, Inc.
Joseph D. Feskanin
Lehigh Valley Electroni cs, Inc.

A. Snowden
Yorkshire Post Newspapers, Ltd.
England

Gerard Lhote
Cogeco
France
James J. Morel
Mandrel Industries, Inc.
Douglas Moyer
The Carpenter Stee I Company
Joseph Padar
Agrico Chemical Company
David John Pargeter
Thorn Automation
England
Ian Hamish Patterson
M. O. D. (Navy)
R. N. Medical School (ARRC)
England

Gabriel E. Galos
White Sands Missi Ie Range

K. R. Peal
Canada Centre for Inland Waters
Canada

A. Gershberg
The St. Lawrence Seaway Authority
Canada

Phi Iip G. Powell
Kodak, Ltd.
England

Dipl. - Phys. Bela Gurath
Institut fur Medizinische Physik
und Biophysik
Germany

E. B. Pray
Sylvania Electric Products, Inc.

Raymond Hedley
University of London
England
Ralph E. Hord
McDonnell Douglas Corporation
Prof. Dr. Peter Ihm
Institut fur Medizinisch-Biologische
Statistik, Germany

Joseph E. Stoyack
Chrysler Corporation
Fredri c M. Strange
Lawrence Radiation Laboratory
University of Cal iforn ia, Livermore
Guy J. LeStrat
LMT
France
Mituo Suzawa
Kikusai Electric Company, Ltd.
Japan
Edwin Tomasi
Molybderum Corporation of America
K. E. Wagner
Electricity Council Research Centre
England
JamesA. Walther
Ramsay Engineering Company
Donald Whitney
Fellows Gear Shaper Company, Inc.

Gunther Reith, Ph.D.
Lehigh Valley Electronics, Inc.

Civi I ingen jor Per Ake Wiberg
Arenco Electronics AB
Sweden
Edward A. Vrablik
Data Technology, Inc.

B. G. Richards
C.S.!'R.O.
Austral ia

L. R. Whigham
Shell Development Company

Lou Ri cketts
The Magnavcx Company
Edouard Roudaut
Centre Nucleaire r.Ie Grenoble, France

Tsunetosi Yamaura
Sumitomc. Electri c Industries, Ltd.
Japan

PDP-9 DELEGATES
Edmund C. Berkeley
Berke ley Enterprises, Inc.
Daniel Brayton
Sanders Associates, Inc.
Wi II iam Broad ley
Learning Research and Development Or.
University of Pittsburgh
Lester R. Bu rre II
Datacap Systems

Ma rk D. Lieberman
Stanford University

Robert B. Weinberg
State University of New York

Robert K. Lindsay
Un iversity of Michigan

F. G. Willetts
University of Aston in Birmingham
England

G. Luetjens
Max- Plank-Institut fur Phys ik &
Astrophysik
West Germany
Dr. M. A. Maclean
Defence Research Telecommunications
Establ ishment
Canada

Prof. J. W. Willhide
Boston Un ive rs i ty
T. S. Yang
Austral ian Iron and Steel Pty., Ltd.
Austral ia

L. M. Caspers
Reacbor Instituut
The Netherlands

Richard E. Maly
Lockheed Missiles and Space Company

Elbert Cook, Jr.
Vanderbi It Hospital

John Margolf
Columbia Un iversity

John Edwards
La Trobe University
Austral ia

A. Meyer
Technological University
Holland

Heinrich Eichner
Institut fu r Kernphysik der
Universitat Koln
Deutschland

J. Morrison
British Aircraft Corporation, Ltd.
England

Herman W. Vreenegoor
National Institutes of Health

L. J. Peek, Jr.
Western Electric Company, Inc.

L1NC AND L1NC-8 DELEGATES

George C. Pegram
Ameri can Science and Engineering Co.

Daniel C. Bergen
Florida State University

Elizabeth Quigg
Lawrence Radiation Laboratory
University of California, Berkeley

Dr. R. Binks
University of Bristol
England

Craig A. Reinhardt
Bell Telephone Laboratories

Prof. G. D. Dawson
University College London
England

Robert M. Freestone, Jr.
Oak Ridge National Laboratory
Eugene A. Fucci
Dartmouth College
Osamu Fu jimura
University of Tokyo
Japan
Mr. Haller
University of Oregon
Dipl. -Ing. Wolfram Haug
Institut fur Statik und Dynamik der
Luft- und Raumfahrtkonstruktionen
West Germany
E. R. Hill
C.S.i.R.O.
Australia
R. J. Hipkin
Riley's Data Share International, Ltd.
Canada
J. J. Jager
Technological University
The Netherlands
Daniel Richard Killoran, Ph. D.
M. I. T. Instrumentation Laboratory
Alan I. Levine
American Science and Engineering

PDP-lO DELEGATES
Walter Colby
Interactive Computing Corporation
Hans- Jurgen Grimm
Universitaet Heidelberg
Germany
Walter A. Miller
Chase Brass and Copper Company, Inc.

Dr. Elhanan E. Ronat
Weizmann Institute of Science
Israel

J. E. Francis
Oak Ridge National Laboratory

(Miss) Sandra A. Sommers
M.i.T. Research Lab. of Electronics

Frederick W. Hegge, Ph.D.
Arizona State University

Fred R. Sias, Jr.
Dr. Masaaki Kashima
University of Mississippi Medical Center Tokyo Teishin Hospital
Dr. James.o. Simpson
Argonne National Laboratory

Dr. Earl J. Kletsky
Laboratory of Sensory Communication

K. D. Smith
General Instrument Corporation

Carl G. Klotz
Western Electric Company

Tom Thacker
Royal College of Art
England

DennisJ. Nichols
University of Wisconsin

L. Richard Turner
NASA - Lewis Research Center

Mr. Vladimir Novak
Czechoslovak Academy of Sciences
Czechos lovak ia

CONTENTS

CECUS FALL
SYMPOSIUM
Abstracts of Papers
General Session

JACK TAR HDTEL

iill1 Iill1iiiill
DEC. 12,13,14,
19B8

Data Acquisition and Control Session

2-6

Education Session

7-8

Biomedical Session

9-10

Interactive Systems Session

11-12

PDP-9 Workshop

13-14

PDP-8 Workshop

14-15

PD P-6/1 0 Workshop.

15-16

Modu Ie/Hardware Workshop

Focal Workshop

Local Users Group Meeting

16.

This issue of DECUSCOPE is a special meeting issue
devoted exclusively to abstracts of papers which wi II be
presented at the forthcoming Fall 1968 DECUS Symposium
to be held on December 12-14 at the Jack Tar Hotel,
San Francisco, California.
All articles originally scheduled for this issue will be
published in Volume 7, Number 5.
Registration information and programs have been sent to
DECUS members and non-members. Additional copies
are avai lable from the DECUS Office in Maynard, or
you may register at the Jack Tar during the meeting.
Abstracts are listed by sessions and alphabetically by
author within the sessions. Asterisk in author line indi cates speaker.

ABSTRACTS

GENERAL SESSION

order of events within an experiment. The computer
runs experiments under control of an external clock,
operating through the program interrupt. An important
feature of the operating system is rapid response to a
clock interrupt, so that timing of events can be quite
precise even with the relatively slow instruction speed
of the PDP-sis. The system was designed so a number
of experimenters can each run his own study with qu ick
transition from one setup to another. Current appl ication
is in a psycholacoustic laboratory in which human observers are run in different experiments on a wide range
of detection and discrimination tasks. The currently
operating experimental compiler and operating system
(PSYCLE) will be outlined, and possible extensions to
other fields will be considered.

A COMPUTER WITH HAND, FEET, AND SOUL
Lester Ernest, Stanford Un iversity, Stanford, Cal ifornia
Activities of the Stanford Artificial Intelligence Project
wi II be sampled, including hand-eye system, a computer
controlled cart, and a music synthesizer.

COMPUTER-ASSISTED INSTRUCTION
Patri ck Suppes, Stanford Un iversity, Stanford,
California
This paper wi II review the development of programs in
computer-assisted instruction at Stanford since early
1963. Detailed examples of curriculum material will be
presented as well as an overview of the computer system
used, beginning with the PDP-1 and moving to the present
PDP-10 configuration. Some forecasts of future deve lopments will be attempted, with special reference to some
of the unsolved problems that need solution.

THE USE OF A COMPUTER FOR AUTOMATIC
GAGING AND CONTROL
Nanalal K. Desai, Bendix A & M Division, Dayton,
Ohio
A digital computer can be used on I ine as a stored
program controller for automatic gaging for transfer type
of machine. The application described here consists of
a transfer type of gaging machine handling about 3,000
parts per hour. LVDT analog signals for length, diameter f
and squareness from gaging stations are furnished to
analog-to-digital converter. The computer samples these
informations and stores them in the core. A bad or good
part is identified by the computer by comparing with
preset nominal values. Bad parts are rejected by the
computer and good parts are stacked according to preset
information. The computer also keeps record of the
material util ized for making parts and material sti II in
process, and it records the information pertaining to the
parts on a strip chart recorder for trend analysis.

DATA ACQUISITION AND CONTROL SESSION
COMPUTER CONTROLLED TIRE FORCE ANALYSIS
SYSTEM
Richard A. Cabot, S. Sterling Company, Southfield,
Michigan
A machine control system has been developed for a
4K PDP-S computer, model ASR-33 Teletype, and DF32
Disc file to control, analyze, and alter the force
characteristics of passenger car tires. The system provides many of the characteristics of large scale timesharing systems while avoiding much of the programming
complexity required in such systems. The control features
of the system include the ability to execute operator
initiated "macro" commands in an on-line mode or in a
batch mode. The ana lysis features of the system range
from storage of digitized data records on the DF32 Disc
file to the computation of Fourier coefficients using the
recently developed Fast Fourier Transform techniques.

A COMPUTER-BASED SYSTEM FOR DATA
ACQUISITION AND ANALYSIS FROM MULTIPLE
GAS CHROMATOGRAPHS
Brad Dewey* and Gary Cole, Digital Equipment
Corporation, Maynard, Massachusetts
DEC's new GasChrom-S System will be discussed. This
system automatically detects peaks and shoulders, calcu lates peak areas and peak retention times, adjusts for
baseline shift, allocates overlapping peak areas, identifies components, applies response factors, calculates
component concentrations by either internal standard
external or area normalization, and types a complete
analysis report. The system is capable of performing
these functions for up to 20 gas chromatographs
simultaneously.

A SYSTEM FOR ON-LINE COLLECTION OF
. REPETITIVE DATA USING THE PDP-sis
C. Douglas Creelman, Department of Psychology,
University of Toronto, Toronto, Ontario, Canada
This paper describes a simple interface and associated
software which enable easy control over the timing and

Wynn Fowler, Psychology Department, Harvard University,
Cambridge, Massachusetts

A DATA ACQUISITION AND REDUCTION SYSTEM
FOR NMR SPECTROSCOPY
Brad Dewey* and Charles Spector, Digital Equipment
Corporation, Maynard, Massachusetts

LEXIGRAPH is an interpretive language which places
a display system and various peripherals in the hands of
researchers unfamiliar with low-level languages. The
interpreter accepts as input a "script II from paper tape or
DECtape. The user may specify the display of text or
arbitrary figures defined in the script. A wide range of
script commands have been implemented. Presentation
and inter-presentation times are controlled (with mill isecond accuracy), and chains of displays may be generated which run off without intervening instructions.
When display segments (texts or figures) are grouped in
lists or strings, attributes of the individual segments
(intensity, origin, etc.) may be varied selectively.

DECs new NMR-8 System for automatic data acqu isition
analysis and control from an MNR spectrometer will be
discussed. The system has such features as sweep control,
time averaging, scope display, integration, plotter
control, and the abi lity to assist in the analysis through
the calculation of realtive peak intensities, peak position in units of chemical shift, resolution enhancement,
spectral comparison, fourier transformation and analysis,
etc. In addition, the NMR-8 can set up and control
the magnetic field homogeneity of the instrument.

SOFTWARE FOR A PDP-8 PULSE HEIGHT ANALYZER
SYSTEM

Subject responses may be recorded via a response box tied
to the information collector, from a Teletype, or by way
of a Iight pen. Acceptable responses or response patterns
are defined in the input script. Logical testing of responses is provided for, and fu II branching capabi Iities
are included. Data (e. g., name of response key and
reaction time) are recorded automatica Ily and stored on
DECtape and may be punched onto paper tape for off-line
I isting at the conclusion of an experiment. The script
can also direct the opening and closing of selected bits
in the relay buffer. This may be used, for example, to
control a remotely located audio tape recorder, recording
subject responses at arbitrary inrervals.

W. J. Edwards, General Chemistry Branch, Atomic
Energy of Canada Limited, Chalk River, Ontario,
Canada
A set of two programs is described which enable a 4K
PDP-8 to serve as a versatile data collection and presentation devi ce for 1" -Spectrometry. The programs are
paper tape oriented and controlled by keyboard commands
through a simple executive.
The first program carries out data collection from external, 1024 channel, analog-to-digital converters,
and provides various enquiry features for the experimenter
to check the progress of the measurements. The output
data tapes from the first program are accepted by the
second program for automatic and unattended production
of hard copy (graphical and/or typed).

The interpreter has been used by behavioral scientists in
a number of areas such as: short-term memory, psycholinguistics, concept formation, visual perception, etc.
Operational for two years, it has undergone continuous
evaluation and improvement and appears ready for general
use.

THE USE OF THE PDP-8 IN AUTOMATED TEST
SYSTEMS AT SANDIA LABORATORIES
Glenn Elliott, Sandia Corporation, Albuquerque,
New Mexico
"SCHLEP" A REAL TIME DATA ACQUISITION
PROGRAM FOR MAGNETO-STRICTIVE SPARK
CHAMBERS

The PDP-8 series of computers is being used frequently
in automated test systems at Sandia Laboratory. Several
system configurations are presented briefly. Emphasis
is placed upon the solution of general problems arising
from their use in a large organization of design engineers
and in application where delivery schedule time scales
are very short. General interfacing methods are discussed and a semi-modu lar approach is shown. Sandia's
method of obtaining programs from an engineering organization where no programming talent previously existed
is presented.

Michael D. Greenblatt, David Rittenhouse Laboratory,
University of Pennsylvania, Philadelphia, Pennsylvania
Schlep is a program which receives data from magnetostrictive spark chambers, condenses, writes on tape,
makes decisions, analyzes, and displays this data. The
experiment in which this program will participate is the
study of the KO long lived meson. Its principle service
is to aid in the debugging and maintenance of the spark
chamber system, but it also serves as a quick way to
throughput large amounts of data. It also wi II make
quick and valuable decisions as to the validity of the
event and, in a low-priority background, will do some
analyzing.

LEXIGRAPH, AN INTERPRETIVE LANGUAGE
FOR GRAPHICS
Dr. Daniel M. Forsyth; Psychology Department,
University of Vermont, Burl ington, Vermont I and

was modified to provide several notable features:
1. aids in controller adjustment, 2. transducer signal
conditioning, and 3. compensation for process nonIinearities. Other features of the control system reduce
operator errors during start-up and operation of the
nitrogen and heat systems.

A VOLTAGE INTEGRATOR INTERFACE WITH
COMPUTER RESET
Stan Hubler, RCA, EASD, Van Nuys, Cal ifornia
An integrator is described which acts as an analog
memory to accumulate and store activity on an analog
input of a LlNC-8 during the relatively long intervals
between the short sampling periods. The integrator is
reset to zero immediately after it is sampled by the
computer. This is accompl ished with a simple hardware
addition to the computer, which is also described. Four
of these integrators are used in conjunction with an
averaging program, AVG 2, similar to AVG 1, previously
described by Richard Harshman and Peter Ladefoged in
the November, 1967, DECUS Proceedings.

The complete programmed system is composed of a
highly integrated set of executive control, input/output
and functional routines which perform the above mentioned control and assist the operator during nuclear
operations.

ON-LINE NAVIGATION AND DATA LOGGING
FOR THE MPL DEEP TOW
Dr. Carl D. Lowenstein, Marine Physical Laboratory,
Scripps Institution of Oceanography, San Digeo,
California

ON-LINE DATA REDUCTION FROM CARY 14,
15, AND 60 SPECTROMETERS
Martin S. Itzkowitz* and Barrett L. Tomlinson,
Department of Chemistry, University of California,
Berkeley, California

The growth of a PDP-8 system used in conjunction
with a towed oceanographic instrument package is
described. The Deep Tow instrument carries sonar
systems which measure its distance from the surface
and from the bottom of the ocean, as well as its distance from several acoustic transponders fixed on the
bottom. In addition, the Earth's magnetic field and
the water temperature are measured at intervals. This
data is telemetered to the towing sh ip and recorded
there. The computer, as directed from the keyboard,
performs ca leu lations on the transponder data to provide a position fix and plots this fix on an X-Y plotter
when commanded. Simultaneously, in a background
mode controlled by interrupts, the computer is gathering
other sonar data, reading the magnetometer and temperature systems, processing this data, and logging it
on punched paper tape.

A 4K PDP-8/S computer with ASR-33 Teletype has
been installed in this laboratory as the heart of an
on-line data reduction system for the Cary 14, 15,
and 60 spectrometers. Data flow is from the spectrometer through a set of Datex mechanical encoders
through an interface designed to our specifications by
Berkeley Scientific Laboratories through the computer
and onto the Teletype both as printout and binary
punchout. The software system includes a rapid
averaging algorithm to eliminate high-frequency noise,
a sl iding thirteen point least-squares curve fitting,
a fully buffered I/o system and a versatile monitor
which virtually el iminates the possibi Iity of unrecoverab Ie operator error.

Several interfaces have been built to make the automatic data gathering possible, they will be described
briefly. Software problems which have arisen during
the operation of these two independent but simultaneous
systems will be discussed, together with possible hardware
additions to make the programmer IS task easier.

A PROGRAMMED CONTROL AND INSTRUMENTATION SYSTEM FOR A NUCLEAR REACTOR

J. R. Kosorok, Battelle Memorial Institute, Pacific
Northwest Laboratories, Richland, Washington
A DEC PDP-7 has been interfaced with a nuclear
reactor instrumentation and control system. The test
reactor's electric heating system, rated at 384 kW,
can heat it to 10000 C. Its graphite moderator is
blanketed with pressurized nitrogen to inhibit oxidation.
The digital computer directly controls the nitrogen and
heating systems and provides operational aids for the
reactor personnel. The central processor has 8K words
of core storage and uti Iizes three DECtapes for bu Ik
storage. In addition to the digital control hardware
for over 100 analog and 190 digital inputs, two unique
features are a three-color, alpha-numeric display
and two six-decade analog-to-digital converter channels.

A PDP-8/S AS A PROCESS-TESTING CONTROLLER
FOR MANUFACTURE OF TANTALUM THIN-FILM
T-PAD ATTENUATORS
H. D. Marshall* and R. L. Siegel, Western Electric
Company, Inc., Allentown, Pennsylvania
A PDP-8/S forms the nucleus of a complex anodizertester for the manufacture of T- Pad Attenuators. Th is
paper describes the basic problems of anodizing and
testing tantalum resistors and the design consideration
of hardware and software to meet this task. The
hardware coverage in this discussion is limited to basic
descriptions of the peripheral equ ipment to allow a more
thorough treatment of the Software Logic.

Eleven closed loops were controlled with a digital simulation of a proportional-plus- integral controller I wh ich

WEATHER AND A PDP-8/S

the c:(-spectra, and recording each spectrum on DECtape
and IBM cards when it is found to be statistically valid.

T. McGovern* and R. E. Archinuk, Assessment,
Computing and Instrumentation Branch, Atomic
Energy of Canada Ltd., Pinawa, Manitoba, Canada

*This work was performed under the auspices of the
U . S. Atom i c Energy Comm iss ion •
THE PRINTING DENSITY ANAL VZER: A SYSTEM FOR
PROCESS CONTROL

The meterological system at Whiteshell Nuclear Research
Establishment includes several instruments for measuring
wind speed, wind direction, temperature and solar radiation. The instruments were interfaced with a PDP-8/s
computer to obtain the data in real time. The data was processed to give mean values over a la-minute interval once
per hour. The results were printed and punched in a code
su itable for further analysis in the computer center. The
problems encountered before and after installation are
discussed.

William A. Minnick* and Charles M. StaseYi !tek
Corporation, Lexington, Massachusetts
The printing density analyzer is a system designed to
rapidly scan photographic film to determine emulsion
density characteristics needed for the dupl ication
printing process. The system data acqu isition and
function control problems lend themselves to an elegant
solution through the implementation of a small generalpurpose digital computer (PDP-8/1).

DATA ACQUISITION AND CONTROL OF A
SPECTROPHOTOFLUORIMETER

The authors discuss a general software approach to the
development of this real time, interrupt-driven system.
Solutions to specific hardware and software problems will
be discussed and resu Its wi II be demonstrated. The paper
will conclude with a discussion of the management
approach employed to minimize the final cost of programming and implementing the computer into the system.

Robert H. Mc Kay*, Frank Neu, and Myron Myers,
Department of Biochemistry and Biophysics, University
of Hawaii, Honolulu, Hawaii
An interface between a spectrophotofluorimeter built
in this laboratory and a standard PDP-8/s computer will
be described. The interface utilizes DEC modules,
stepper motors for wavelength and polarizer positioning,
and a Hewlett-Packard #2401-C Integrating Digital
Voltmeter for data acquisition. Light source fluctuations
are controlled using a mon itor on the incident light, a
v-f converter, and feeding this in as an external time
base for the DVM.

A MULTI-STATION DATA ACQUISiTION AND
CONTROL SYSTEM
Thomas H. Rau* and Howard Borer, The Dikewood
Corporation, Albuquerque, New Mexico
The presentation is broken into three major sections:
A. System Design and Control - Covering the basic
system design, creation of the system in a IIfresh-start II
situation, and the overall system control operation.

Software developed for this application will also be
described briefly.
The instrument is capable of plotting either corrected
fluorescence excitation or polarization spectra, with
a data collection interval as low as O. 5mjJ.

B. Multi-station Data Acquisition - Covering the
data acquisition process, optional interrupt processes,
reformatted data-storage, and restart capability.
C. Data Reduction (Qual ity Control) - Covering
report generation, data history file creation, data
control information changes, and system shut down.

AUTOMATED ALPHA PULSE ANALYSIS - PART 11*
G. G. McMillan* and J. E. Evans, Lawrence Radiation
Laboratory, University of California, Livermore,
Cal ifornia

A MODULAR ANALOG DIGITAL INPUT SYSTEM
(ADIOS) FOR ON-LINE COMPUTERS

A computer program has been written to control the
accumulation of alpha particle spectra by several pulse
height analyzers. This program was written specifically
for a 4K PDP-8. The computer is equipped with DECtape,
an ASR-33 Teletype, an IBM 526 Card Punch, and one
to four Nuclear Data ND-130 Pulse Height Analyzers.
Each pulse height analyzer contains 512 channels that
are spl it into four quadrants of 128 channe Is each. Each
quadrant is equipped with a six-position automatic sample
changer, thus as many as 96 samples can be programmed
for spectral analysis. Significant features of the program
include the acceptance of identification and control
information from the Teletype, rotation of the sample
changer to the correct position, periodic integration of

D.A.H. Robinson*, R. W. Kerr, H. P. Lie, and
G. L. Miller, Bell Telephone Laboratories, Inc.,
Murray Hi II, New Jersey
A system is described which is designed to permit the
user of an on-I ine computer to achieve a desired hardware
configuration with a high degree of flexibility. The
system uses modular plug-in units inserted in bins which
are interconnected by a common two-way analog and
digital data bus. The system is designed for a PDP-8
computer and can be expanded, as needed, to hand:e
up to 60 modules.
The modules, which were designed to provide a simple,

flexibility of subroutine usage, a linking loader, and an
easily modified executive routine.

low cost means of analog and digital measurement and
control, are of four types. These are a digital inputoutput register, a scaler, a relay bank, and a power
supply. The design of the modules takes advantage of
the versati I ity of the computer in a number of ways,
including previsions to allow the computer to check
each modu Ie for proper operation.

A presentation of the hardware and software parameters
considered in establishing a computer-controlled data
acquisition system for general purpose use will be given.
A description of how VIDAC meets these requirements,
followed by three specific examples of V IDAC's use
encompassing widely varying data acquisition requirements,
will be presented.

Several system configurations are described. Included
are examples of the use of the system to automate such
things as the testing of spacecraft experimental hardware,
and the measurement of Hall effect coefficients over an
extended temperature range.

A FLEXIBLE DATA ACQUISITION AND CONTROL
SYSTEM UTILIZING A PDP-sis

(This paper will also be presented at a session of the
FJCC on Laboratory Automation.)

G. E. Stokes* and D. R. Staples, Idaho Nuclear
Corporation, Idaho Falls, Idaho

EXPO, A FLEXIBLE PDP-S DATA-ACQUISITION
PROGRAM

A multi-scaler data acquisition system with sensing and
feedback controls to the experimental devices has been
designed around a PDP-sis computer. This system has
been used on a number of experiments with a variety of
control requ irements. In each case the configuration was
integrated into the experimental setup with a minimum
of hardware changes. The computer interface includes
four 12 bit scalers, a real time clock, a 10 bit ADC, a
6 bit relay divider, pulse generators for driving pulsed
motors, and a 10 bit DAC. The interface will be described
and techniques for programming the device for different
experimental requirements will be discussed.

Bruce Arne Sherwood, Synchrotron Laboratory,
California Institute of Technology, Pasadena, California
EXPO is a program for a 4K PDP-S with EAE wh ich reads
various kinds of data from experimental apparatus, optionally logs data on magnetic tape, and accumulates
one- or two-dimensional histograms of selected variables.
From the Teletype keyboard the user defines which
variables are to be histogrammed and under what conditions; variable names are four-letter mnemonics and
numerical parameters are decimal. Also, from the
keyboard the user may call for Teletype or scope output
of histograms with some control of format; output may
occur simultaneously with data acqu isition. EXPO
proved very useful in a high-energy physics experiment
and may have wider applicability.

COMPUTER CONTROL OF HYDRAULIC TESTS

L. A. Thomas, New Brunswick Research and Productivity
Council, Fredericton, New Brunswick, Canada
This paper describes the use of a PDP-siS computer in
obtaining the characteristics of hydraulic pumps, motors,
and transmission systems. The aim of this work is to
provide a rapid and accurate method for carrying out
such tests.

REAL TIME ACQUISITION AND DISPLAY OF
MASS SPECTRA
P. D. Siemens, Lawrence Radiation Laboratory,
University of California, Livermore, California

Some of the interface problems, methods of handling
the data, and programming techniques which are peculiar
to th is type of system are discussed.

A program package has been deve loped to perform
real time data acquisition and display from a mass
spectrometer. In this particular case the data acquisition routine performs multisumm ing-scal ing; but, with
minor changes, the package could do signal averaging
or pulse height analysis.

A programm ing language has been written, making use of
macros and an operating system, which provides the user
with a powerful test, control, and data acquisition system.
QUEUE STRUCTURES IN A PDP-9 DATA
ACQUISITION SYSTEM

Through a keyboard mon itor, the operator has complete
control of the experiment with a variety of commands
avai lable to him. Among these are commands which
provide for: control of the data acquisition, real time
log or linear displays, data output on paper tape,
Teletype, DECtape, or Calcomp, and data reduction
(peak stripping and the calculation of isotope ratios).

Barry L. Wolfe* and Sol B. Metz, Information
Control Systems, Inc., Ann Arbor, Michigan
The paper describes methods of implementation of a
data acquisition system in a manufacturing environment
on an SK PDP-9 with DECtapes. The system maintains
piece counts and updates production schedu les, logs
production equipment, states changes, reports exception conditions, and processes real-time inquiries.
The system uti lizes queue structure for in-process data
in order to conserve and dynamically allocate core
storage.

VIDAC - A DATA ACQUISITION PROGRAM
Robert W. Skyles* and Noel P. Lyons, VIDAR
Corporation, Mountain View, California
VIDAC is a data acquisition system program for the
non-sophisticated computer user. Its features include

EDUCATION SESSION

laboratory experiments and research into many aspects of
digital computer engineering.

A GENERALIZATION OF COMPUTER-ASSISTED
INSTRUCTION

Equipment available includes small-scale digital computers, analog computers, logic labs, and data sets.
The laboratory also contains two unique devices interfaced
to a PDP-8. They are the IIMicro-8 11 (a device for external
control of PDP-8 internal micro-operations) and a powerful
patchboard-oriented logic breadboard device.

Dr. Ludwig Braun, Polytechnic Institute of Brooklyn,

Biooklyn, New York
Also described is the method by which this equipment is
integrated with a sequence of computer engineering courses
offered in the Department to provide extensive laboratory
experience in such areas as small computer programming
(PDP-8 and L1NC-8), computer organization and operation
(Micro-8), logical design (logic labs and special patchboard device), and hybrid computer systems (L1NC-8/AD-24).

A description is given of the Huntington Computer
Project, its objectives, and its methods of operation.
Its ob jectives are:

1. To explore the potential impact of the computer on
learning in high school courses in biology, chemistry,
mathematics, physics, and social studies. In this
project, the computer is used as a high-flexible laboratory
rather than as a IIprogrammed-instrumentalll device.

THE IIMICRO-8 11
2. To explore the relative merits of time-shared and
stand-alone computing.

Fred F. Coury, Department of Electrical Engineering,
University of Michigan, Ann Arbor, Michigan

3. To attempt to determine the differential effect, if
any, of socio-economic condition on the learning experience of participating students.

The IIMicro-8 11 is a device designed to demonstrate and
provide insight into the detai led internal operation of a
digital computer, specifically a PDP-8. It consists of a
pushbutton control panel, minimal internal circuitry,
connecting cables, and wiring additions to a standard
PDP-8.

Some of the programs already written and under development are described.
A compiler and operating system which implements the
full capability of BASIC on a PDP-8/1 is described.

The pushbuttons are so arranged on an illustrated front
panel, outl in ing the major functional blocks of the
PDP-8, that they show the micro-operations which can
be performed on and befween the various blocks.
Pushing the appropriate button causes the desired operation to be performed actually within the PDP-8.

CAl APPLICAT ION AT STANFORD
Dow Brian, Institute of Mathematical Studies in the
Social Sciences, Stanford University, Stanford, California

Toggle switch registers simulate data input buses, and
the resu Its of an operation are visible in the PDP-8
console indicators. External logk can be used in place
of the pushbuttons, allowing student-designed control
units to manipulate the PDP-8 registers.

This paper describes the system configuration designed to
run several hundred Teletype terminals in computer-assisted
instruction. Particu!ar emphasis is given to the method of
generating audio output. Many CAl appl ications, such as
elementary reading and foreign language, require computercontrolled speech to be maximally effective.

When the IIMicro-8 11 is disabled, it has no effect on the
standard operation of the PDP-8 to which it is connected.

A vocabulary is constructed by digitizing individual words
and storing them on a disk file. Messages are then constructed
in real-time by outputting sequences of words through a specially constructed digital-to-analog multiplexer channel. The
system resources and software necessary to operate 72 audio
stations simultaneously with other CAl and time sharing activities are described in detail.

A PATCHBOARD-ORIENTED DIGITAL LOGIC
BREADBOARD
Fred F . Coury, Department of Electrica I Engineering,
University of Michigan, Ann Arbor, Michigan

Fred F. Coury, Department of Elec,trical Engineering,
Un iversity of Mi chigan, Ann Arbor, Michigan

This paper describes a prototype patchboard breadboarding device currently in use at the Department of
Electrical Engineering, University of Michigan. The
purpose of the device is to allow students to carryon
advanced digital design projects in parallel and with
minimal equipment expenditure.

This paper describes a laboratory faci Iity currently in use
at the Department of Electrical Engineering, University
of Michigan. This facility provides for a wide range of

The patchboard-oriented device can be compared, in
principle, to a standard DEC Logic Lab but is much
more powerful in many respects. It provides many more

THE COMPLETE COMPUTER ENGINEERING
LABORATORY

avai lable module positions, a much greater range of
support functions, a greatly expanded control panel,
access to all standard PDP-SI/O lines and IIMicro-S II
control lines.

is investigated. The algorithm of the solutions and the
manipulations of the matrix equations are programmed utilizing
direct access devices. Results of this investigation indicate
that the rate of convergence of the method decreases rather
rapidly with increase in the number of variable parameters
both in the linear and nonlinear theory of plates. Results
showing the effect of each of the plate parameters on the
rate and pattern of convergence are plotted graphically.

The principal difference, however, is that all of these
signals are mapped into a 34 by 66 pin patchboard
receptacle. This allows for off-line wiring of several
devices on removable patchboards and time sharing of
the main facility for on-line debugging and demonstration.

CONVERSATIONAL BASIC ON THE PDP-S LINE
Devices built using this facility are described, and an
extension of the patchboard concept is discussed.

Bud R. Pembroke and Dave Gillette, Computer Instruction
NETWORK, Salem, Oregon
This paper will concern itself with the use of CINET -BASIC
in the classroom. It will include sample problems and a
discussion of the variations between this BAS IC and other
existing BAS IC languages. CINET -BAS IC (Computer Instruction
NETwork's BAS IC) was written using FOCAL's subroutines for
the standard PDP-S series with 4K memory and ASR-33
Teletype.

A LIMITED MULTI-TERMINAL SYSTEM FOR CAl
Daivd A. Ensor, Department of Computer Applications,
The Ontario Institute for Studies in Education, Toronto,
Ontario, Canada
The paper describes a suite of PDP-9 programs to provide a
multi-terminal "CAIII faci I ity for both laboratory experimental
use and also to give interested school boards the opportun ity
for some on-I ine experience. The OISE configuration is
briefly outl ined, and both the author language and its processors are discussed in addition to the mu Iti-access software
and the batch-time system. It is hoped eventually to run up
to 64 terminals through a I ine concentrator with the system as
a foreground program under the Advanced Software System.

Panel Discussion
TRAUMA INVOLVED IN STARTING A NEW
COMPUTER SCIENCE PROGRAM AT A
UNIVERSITY
Dr. Wayne A. Muth, Moderator
Southern Illinois University, Carbondale, Illinois

LOGO - A PROGRAMMING LANGUAGE FOR
CHILDREN, TEACHERS, AND MATHEMATICIANS

Discussion would include curriculum and program
requirements; options and/or electives within a program;
Ph.D. vs. M.S. vs. V.S. vs. two-year technical
programs (trade-offs and considerations); staffing requ irements; interaction with other departments; startup
of a new program us i ng ava i Iab Ie person ne I, courses,
and other resources.

Wallace Feurzeig, Bolt Beranek and Newman,
Cambridge, Massachusetts
Logo was expressly designed as the starting point for a
new kind of curriculum in which programming languages
are used to provide a conceptual framework for the
teaching of mathematics. The structure of Logo embodies
mathematically important ideas with minimal interference
from programming conventions. It permits the expression
of mathematically rich non-numerical algorithms as well
as numerical ones. It can be introduced to third-graders,
for simple tasks, with relative ease. Carried forward,
it may contribute markedly toward increasing Iiteracy in
the skills of logical thinking and expression.

PATTERN AND RATE OF CONVERGENCE OF THE
PERTURBATION TECHNIQUE IN THE TREATMENT OF
LINEAR AND NONLINEAR PLATE PROBLEMS
Dr. S. F. Ng, Department of Civil Engineering,
University of Ottawa, Ottawa, Ontario, Canada
An approximate method based on the Perturbation technique
is used to solve the small and large deflection problems of
the bending of circular, elliptical and skewed plates resting
on an elastic support. The influence of the variable parameters such as the plate aspect ratio, skew angle, poisson's
ratio and foundation modulus on the pattern of convergence

USE OF A PDP-8/s COMPUTER FOR ON-LINE
MONITORING AND CONTROL OF BLOOD GLUCOSE
I N HUMAN SUBJECTS

BIOMEDICAL SESSION

Arnold Henry Kadish, M.D.*, and Robert L. Litle, Ph.D.,
Cedars Sinai Medical Center Research Institute, Los Angeles,
California
ARBUS - AUTOMATED RESERVATION AND BED
UTILIZATION SYSTEM

During the past several years, a continuous mon itor for blood
glucose has been used to study the response of human subjects
to various inputs thus providing data for model ing the human
homeostatic system. Recently, a PDP-8/s computer has been
incorporated into the system making possible on-line reduction
of the data. In addition, a control system has been developed
whereby computer derived control signals regu late glucose
infusion rates to the subject. This has made possible more detailed studies of human natural control mechanisms.

Robert P. Abbott* and Judith Ford, Research Data Faci Iity of
the Pacific Medical Center and the Institute of Medical
Sciences, San Francisco, California
ARBUS was originally designed to meet the two specific hospital needs as implied in the name . Subsequently, the goals
were modified to include other scheduling, inventory, and
communication needs within the hospital environment. The
system employs the concept of a small computer at the hospital
site with a communication I ink to a larger computer located
elsewhere. Terminals located throughout the hospital are
connected to a small computer-the PDP-8.

SIMULTANEOUS FILE PROCESSING AND PATIENT
MONITORING WITH A PDP-8/1

DIAGNOSTIC USES OF AVERAGED EVOKED
POTENTIAL IN CLINICAL NEUROPSYCHIATRY

M. J. McKeown* and R. Bush, Department of Obstetrics
and Gynecology, The Chicago Lying-In Hospital, Chicago,
Illinois
There is increasing recognition that one of the more effective
ways to fully utilize the capabilities of the large versatile
third-generation computers is with local small processors for
data concentration and transm iss ion.

Dr. Enoch Callaway, Langley Porter Neuropsychiatric
Institute, San Francisco, California
Over the past four or five years, small high-speed digital
computers have been used to process human brain waves
in a variety of ways that have potential clinical value.
The usual procedure has been to digitize a set of potentials
from the head and treat these by a variety of techniquesthe most popular of which is averaging sequences of potentials with each sequence having the same time relation to
some recurrent event. These averages, frequently referred
to as Averaged Evoked Potentials or AEP's, have been put
to a variety of uses. The purpose of this paper is to review
some of these uses.

The Chicago Lying-In Hospital is investigating the effectiveness
of automated data processing in improving prenatal care.
Main file processing is done on a 360150. An on-line subset
resides on DECtape on the PDP-8/1. This subset is accessed
through a Teletype on the labor floor.
Initial development in on-line monitoring of high-risk obstetric patients has been accomplished with a L1NC-8. l

1 McKeown, M. J.; Bush, R.; and Domizi, D.; A computer
system for the monitoring of intensive care obstetric patients.
J. Reprod. Med. 3: 275-277 (1968).

LIFE WITH A LABORATORY COMPUTER SYSTEM

Communication to the 360150 by the PDP-8/1 is over Dataphone into a dedicated 4K partition.

Irwin R. Etter, The Mason CI inic, Seattle, Washington
The Laboratory of the Mason Clinic and Virginia Mason
Hospital has used a totally dedicated computer system for the
past two and a half years. During that time the laboratory
staff has become highly dependent on the functioning of the
computer. Despite great increases in work load in the laboratory, the size of the staff has been held constant, with a
decrease in direct I ine personnel. The use of the computer
allows the staff to pay greater attention to the technical
aspects of the laboratory while the computer handles an ever
growing portion of the clerical chores. The role of the computer is continually being modified as our experience increases. These changes are· due to both the techn ica I changes
in the laboratory and to revision of our concepts of the role
of the computer. The success of our program is due to the
high reliability of the computer system as well as the widespread interest in data processing among the staff.

FLIRT - FILE LANGUAGE IN REAL TIME
K. R. Morin, St. Paul IS Hospital Laboratory, Vancouver,
British Columbia, Canada
FLIRT, an intermediate-level language which directs
file transactions between Teletype, core, and DECtape
is being developed for the PDP-9. A FLIRT fi Ie may
contain any number of records; each record contains
alphanumeric elements of variable length (6-bit characters)i an element can be a simple item or another
record (nesting limited to 4-deep). Each file is stored
in as many 64-word blocks on DECtape as necessary.

FLIRT contains abour 20 verbs, e. g., ASK (ask question
on Teletype and store response in core), MOVE (move
item{s) from one record to another in core), WRNFL
(write a new file on DECtape), and LOCREC (locate
a record on DECtape which meets the specified conditions). Four verbs direct movements to/from a
queue-buffer area. Record formats and most mnemonics
are user-defined. The FLIRT subroutines will occupy
about 5 K of PD P-9 core.

v isua I d isp Iay and photom i crogra ph i c images, and (3) photomicrograph pro jector .

Significant contributions in this system are in the use of a
Iight pen with visual display as a data inputting device
instead of mere functional control of the computer via
interrupt mode and in the optical image superposition
technique.
The boundary of a cell or nucleolus is traced with a light
pen, and the area is computed immediately within three
percent. Real microscopic image is also successfully processed with CCTV.

A COMPUTER CONTROLLED SARCOMERE LENGTH
CLAMP
Paul J. Paolini, Jr., Division of Biological Sciences,
The University of Georgia, Athens, Georgia
An experimental method has been devised to allow computercontrolled determination of the stress-strain curve which
characterizes the series elastic component (SEC) of an excised
vertebrate striated muscle. This information is used to derive
a shortening vs. time waveform of the muscle1s SEC during an
isometric twitch: the calcu lated curve is then mechanically
appl ied to the muscle during a twitch so that, on the average,
no SEC shortening occurs and contractile component elements
(the sarcomeres) remain at constant length. The muscle1s
tension and volume change vs. time waveforms are recorded
with this condition imposed. The system employed to control
and monitor contraction parameters (with length, tension,
and volume transducers) consists of a 4K PDP-8 computer, a
multiplexed AFOl A A-to-D Converter, a set of programcontrolled relays, and a Type 34D Display to provide the
analog input for a servo motor which sets muscle length, as
well as to interface a display oscilloscope and X-Y recorder.
Program output consists of many keyboard selectable types of
waveform displays, each with alphanumeric display of cal ibrated sensitivities and time scales.

A DESIGN CRITERIA FOR DDC SYSTEM FOR ULTRASONIC
IRRADIATION OF BRAIN
Dr. Hideo Seo, Biophysical Research Laboratory,
University of Illinois, Urbana, III inois
Ultrasonic irradiation for quantitative neuroanatomy at BRL
requires 0.001 inch accuracy positioning of the transducer
so that carefu Ily controlled lesion can be introduced without
destroying the interven ing brain tissue except at its focal
point.
The above operation is done manually until the forthcoming
use of automatic DDC System to prevent human errors and
reduce operation time.
This paper presents the basic procedures and steps desired
for optimum system design for automatic irradiation. The
associated hardware for the PDP-8 interface and software
programs both for the system diagnostics and for the routine
operating procedures are discussed.

OBTAINING A CASE HISTORY BY COMPUTER
Theodore R. Sarbin, Human Factors Laboratory, University
of California, Berkeley, California
In the course of an initial visit, an optometrist obtains a
case history from the patient. This paper describes a program
and allied hardware devices which are used to obtain this
information directly from the patient. This Computer Generated Audio System using a PDP-8 may be used for any type
of interrogation, including general patient history.

DESIGN PHILOSOPHY OF AN INTEGRATED
LABORATORY-HOSPITAL INFORMATION SYSTEM
Garth Thomas, Systems Research Department, The Ohio
State University Hospitals, Columbus, Ohio
The integration of a Laboratory Information System being
developed within the larger framework of a Hospital
Information System will be presented. Using a small
L1NC-8 computer to perform the required functions within
the clinical laboratories and divorcing its operation from
any required hospital functions, provides the maximum
flexibil ity in its uti I ization within the laboratory operation.
Whereas, those functions which can be performed more
conveniently and economically by a central computer
facility can be used to maximum advantage without any
major effect upon efficient operation of the laboratory.
The significant consequences, advantages, and disadvantages
wi II be discussed within the framework of the genera I system
design phi losophy employed.

System demonstrations in Berkeley can be arranged upon
request.

AN APPROACH TO MICRO-IMAGE ENCODING
AND AREA SCANNING OF THE CELLS OR
NUCLEOLI OF BRAIN
Dr. Hideo Seo, Biophysical Research Laboratory,
University of Illinois, Urbana, Illinois
A new system consists of the three subsystems, namely,
(1) PDP338 - PDP-8, (2) optical system which overlays

INTERACTIVE SYSTEMS SESSION

therefore, designed using: 1 ~ hybrid computation
multiplying digital-analog converters and summing
ampl ifiers, 2. data-compression by storing 6-bit X
and 6-bit Y deflections in a single word, and 3.
adoption of databreak data-transfer under control of an
automatic-sequence-plotting interface.

GRAPHICS - TERMINAL COMMUNICATIONS
PACKAGE

This interface permits highly-detailed, realistic contactanalog displays to be generated on line whi Ie sti II

Barry R. Borgerson, Project Genie, University of
California, Berkeley, California

a! lowing central-processor time for performance evalu-

ation.
The SDS-940 user program communicates with the
display hardware through a commun i cat ions package
operating between the SDS-940 and a PDP-5 whidi
shares memory with the display controller. By
transferring and buffering all data and control words,
the communications package handles the timing
problems for the user.

Hardware and software problems will be discussed.

FAST FOURIER TRANSFORM TECHNIQUES USING
A DRUM FOR MEMORY EXTENSION
Ric C. Davies, Phillips Petroleum Company, Idaho Falls,
Idaho

With the aid of an unpluggable hardware addition,
the PDP-5 runs under an interrupt monitor which
handles all of the I/o for its end of the communications
package.

A fast Fourier transform subroutine package which is
FORTRAN compatible has been developed for a basic
PDP-9 computer to transform any type of discrete data.
A 128K RM09 serial drum is used to readi Iy access and
store the data during computation of the fast Fourier
transform. A 339 Display unit is used to display the
original data and the transformed data separately or
simultaneously for comparison. A paper tape punch
option suppl ies the user with permanent copies of
portions or of all the data.

The actual transmission between the two computers is
done over a high-speed, half-duplex Iink and a lowspeed, full-duplex path. All of the transfers over the
half-duplex line are set up on the low-speed path.

AN EXECUTIVE FOR A REMOTE INTERACTIVE
GRAPHICS TERMINAL
A SEISMIC DATA ANALYSIS CONSOLE
Claudia G. Conn* and Pamela T. Hughes, Computer
Sciences Corporation, Huntsville, Alabama

Philip L. Fleck, M.1. T. Lincoln Laboratory,
Lexington, Massachusetts

This paper describes the development of an executive
system for a PDP-9/339 used as a graphics terminal
remoted to a tr i pie processor UN IV AC 11 08. It
includes the design of a higher-level interactive
programming language which is processed interpretively
by the executive system. This language allows the
programmer to monitor, direct, and respond to operator actions at the scope and to communicate with the
central site computer without requiring any knowledge
of the terminal hardware or software. This executive
system handles all I/o, interrupts, allocation of free
storage, tracking, and display file management.

DESIGN AND USE OF A DATABREAK DISPLAY
FACILITY FOR PDP-8

A software system for a PDP-7 digital computer with
a cathode ray tube display has been designed to
process seismic data. The system perm its quick visual
inspection of digitized data and allows easy appl ication
of powerfu I programs wh ich operate on the digitized
data or on the resu Its of previously used programs.
Some operations which can be performed are: epicenter
location, beamforming, magnitude, complexity and
spectral ratio computation, filtering, autocorrelation,
Fourier transformation, sonogram generation, and
automatic event detection. A human operator is in
the processing loop, inspecting the output at each step
before applying the next. This system has greatly increased the speed and efficiency of much of our seismic
data processing.

E. R. F. W. Crossman, Ph. D., Department of Industrial
Engineering and Operations Research, University of
Ca Iifornia, Berke ley, Cal iforn ia

REAL-TIME COMPUTING WITHIN A TIMESHARING SYSTEM
Peter Hurley, Digital Equipment Corporation,
Maynard, Massachusetts

Our current research requires the use of contact-analog
displays simulating the motion of a landscape as seen
in perspective from a moving automobile or other
vehicle. By employing geometrical approximations and
table-look-up methods, it proved possible to generate
. only marginally adequate displays using the Type 34D
display-controller. An improved display controller was,

Th is paper describes the capab iii ty of the PD P-l 0 to
perform on-line, real-time tasks concurrently with
time-sharing activity. The PDP-10 is not limited to
a single real-time job, nor is it Iimited to running

solely in a background batch mode during real-time
operation. While hand ling several real-time jobs,
such as on-line process control or data acquisition, the
PDP-10 system can support a complete time-sharing
service including simultaneous data processing jobs,
batch jobs, and program development. Of prime
importance is the consideration of the general real-time
problems including high priority scheduling and real-time
queues. The paper discussed the implementation of some
of these real-time features and is supplemented by
examples of the techniques employed at existing PDP-10
installations. The paper concludes with a description of
the design goals for a multi-user, real-time system which
allows the running and testing of undebugged real-time
jobs without degrading the performance of other jobs.

A SIMPLE NEW DISK MONITOR SYSTEM FOR
THE PDP-8
Theodore R. Sarbin* and Richard A. Roth, Human
Factors Laboratory, University of California,
Berkeley, California
A simple disk based Real Time Monitor System is
described. Some of the criteria used in designing the
system are discussed as well as the command language
developed. The system is based on a one half million
word Datadisc and a 4K PDP-8.

INTERACTIVE DEBUGGING UNDER SIMULATION
GRAPHIC SOFTWARE SYSTEM USING A PDP-9/339
SUPPORTED BY AN RM09 DRUM

David J. Waks, Applied Data Research, Inc.,
Princeton, New Jersey

Glen C. Johnson, Atomic Energy Division, Phillips
Petroleum Company, Idaho Falls, Idaho

Debugging programs for small computers is hindered by
the lack of adequate memory, proper hardware, and
peripheral equipment on the machine on which these
programs are ultimately to be run. This paper proposes
that comprehensive simulators for small computers be
developed expl icitly for interactive debugging and be
run on larger computers with adequate memory, peripherals
and hardware to completely check out the program written
for the small computer. This technique has been used at
ADR for over two years, debugging large, real-time PDP-8
programs on a PD P-7 .

A package of PDP-9 subroutines have been developed
to facilitate the use of the 339 Display and conserve
storage by creating display files on the RM09 drum.
This package requires 270010 PDP-9 core locations, an
RM09 drum, and a 339 Display unit. These subroutines
are both MACRO-9 and FORTRAN IV compatible and
create display fi les in vector, text, and graphplot modes
with parameters. Routines to initial ize the 339 and
service the Iight pen and function box are provided.
A file swapping technique, from drum to core, permits
execution of large fi les of display commands in a small
core buffer.

THE USE OF COORDINATE MEASURING MACHINES
FOR THE DIRECT PRODUCTION OF N/C MACHINE
TOOL TAPES

INTERACTIVE SYSTEMS APPLIED TO THE
REDUCTION AND INTERPRETATION OF
SENSOR DATA

Neale F. Koenig, Information Control Systems, Inc.,
Ann Arbor, Michigan

Charlton M. Walter, Air Force Cambridge Research
Laboratories, L. G. Hanscom Fie Id, Bedford,
Massa c huse tts

Digitizer appl ications of Coordinate Measuring Machines
(CMM 's) are directed toward the production of N/C
tape for machining complex two- and three-dimensional
part configurations. This task is best performed in a
man-computer coal ition, i. e '/ the man directs the
CMM over the part and the computer performs the mathematical computations and translation of data to the desired tape format.

The potential and limitation of various modes of
man-machine interaction, involving keyboards,
light pencils and color displays will be discussed
and illustrated in the context of the signal data
reduction, model ing, and interpretation problem
area, The requirement for manipulating large bases
of sensor data imposes serious constraints on the
abi! ity of any interactive system to satisfy such
incompatible requirements as flexibility of modes
of interaction, speed of interaction, and abili-ty
to admit multiple users. Slides and short movie
sequences will be shown to demonstrate both the a
advantages and drawbacks of a number of "problemoriented II modes of interaction. The uti Iity of various
types of data display, such as classical isometric
signal representation, will be contrasted with more
abstract projection in N-space techniques.

In order to achieve the most cost effective (i. e., low
cost, high effectivity) hardware system, a great deal of
concern must be paid to the development of associated
computer software. Thus, such techniques as foreground/
background and priority interrupt processing must occur
to effect total utilization of a small, inexpensive on-line
computer interfaced to the CMM. Such a system has been
developed for the production of N/C machine tapes to
digitize turbine blades and is fully described in the text.

PDP-9 WORKSHOP

2. Multi-user FOCAL system which may operate as the
Foreground or Background job under control of the B/F
Monitor System.
3.

PDP-9T TIME-SHARING: PROGRESS REPORT #3

The 339 Software Package.

On Saturday, December 14, 1968, the PDP-9 equipped
with 32K of core memory, API, EAE, Memory Protect,
LT19 with four KSR-33 Teletypes and five DECtapes
along with knowledgeable DEC personnel will be
available the entire day for the purposes of problem
solving and specific demonstrations.

D. M. Forsyth* I Un iversity of Vermont, Burl ington,
Vermont! and M. M. Taylor, Defence Research
Estab Iishment Toronto, Downsv iew, Ontar io, Canada
The paper assumes acquaintance with "PDP-9T: TimeS har i ng for the Rea 1-Time Laboratory II (T ay Ior, Forsyth,
and Sel igman, Proceedings of the DECUS 1967 Fall
Symposium). We report a significant set of alterations
to the hardware specifications and progress on two
separate monitor systems. The hardware changes
dramatically reduce core usage and disc-swapping
overhead for shared pure procedures by providing
64-word "supplementary memory blocks II within the
monitor space. A supplementary memory block may be
accessed only by a task which "owns" or "Ieases" it,
but such a task accesses it as readi Iy as the task accesses
its own main working memory. Supplementary memory
may be read-only or read-write, but no program material
may be executed in it. It is intended for the impure
parts of pure procedures executed in read-only pages of
the working memory. The same hardware modification
expands the possible independent entry points to Vector
Service Routines from 256 to 16,384.

OPERATING THE KEYBOARD MONITOR SYSTEM
FROM A DISK
C. W. Richardson, Atomic Energy Division, Phillips
Petroleum Company, Idaho Falls, Idaho
The Disk Monitor Program is designed to allow efficient
use of a disk or drum by the Keyboard Mon itor System.
A basic PDP-9 with DECtape and any size drum or disk
is sufficient to operate the monitor. DECtape is used for
permanent storage. There is no need for protected or
reserved areas for system programs since only those programs
being used need be on the disk. System and user programs
and user data sets are transferred from the DECtape to the
disk for fast access by the computer. The time required for
such tasks as program editing and compil ing can be reduced
by a fa ctor of 10 •

The time-sharing software is being done in two stages.
A "minimonitor," currently being debugged, will be
used to permit simple multiprogramming for real-time
users and as a test bed for modu Ies of a lima i n mon itor II
which will supersede it next year. The minimonitor
supports multiprogramming only among user machines
which reside totally in core and does not permit "pageturning. II With the later addition of disc-swapping for
entire user machines, the minimonitor system should
support one or two fast-response experiments simultaneously
with 3-4 conversational mode Teletype-controlled programs
plus a batch-processing background operation. The
Guaranteed Maximum Latency structure (Taylor, Forsyth,
and Seligman, op.cit.) will not be implemented in the
minimonitor but forms the basis of scheduling for the
main monitor.

REVISED SUBROUTINE LIBRARY FOR EAE PDP-9
Turner~ E. C. Itean, and Paul Manos, NASALewis Research Center, Cleveland, Ohio

L. R.

A new Iibrary of subroutines for floating-point arithmetic
and mathemati ca I fun ct ions has been spec i fied and is
nearly complete. As of September 5 it is undergoing
tests for compatabil ity with the existing FORTRAN
compi ler. It is expected that the function library,
except perhaps for exponentiation, will have been tuned
up and well tested by December. The complete specifications will be briefly reviewed, and modifications for
the user who wishes to use only single or only double
precision operations will be discussed as will proposed
(hopefully minor) modifications to the compiler and
executive system.

PDP-9 MONITOR SYSTEM WORKSHOP
David Leney and James Murphy, Digital Equipment
Corporation, Maynard, Massachusetts
This lecture, discussion session, and demonstration
is directed towards the presentation of major new
developments in the PDP-9 ADVANCED Software
System and towards the solution of existing trouble
areas of genera I concern.

FASBAC PDP-9 TIME SHARING OPERATING SYSTEM
V. J. Zapotocky, University Computing Company,
Dallas, Texas
The U. C.C. FASBAC System provides for remote access
to a general-purpose file editing capability and a string
handling programming language. Input files may be
UNIVAC 1108 program files or data files which are to be
subm itted throu~h direct access to run on the 1108.

The new developments include:
1. Background/Foreground (two user time sharing)
Mon itor System.

The time-sharing operating system has been implemented
on a 32K PDP-9 with a 524K drum and a specially built
controller to allow sharing of a FASTRAND mass storage
device with the 1108 and direct core-to-core transfers
betw~en the PDP-9 and 1108. This paper consists of a
functional description of the PDP-9 operating system and
some implementation problems which should be of common
interest to PD P-9 users.

OS/8: OPERATING SYSTEM FOR PDP-8
Russell B. Ham, U.S. Public Health Service,
Winchester, Massachusetts
OS/8 is a DECtape-based operating system for the PDP-8
which includes a set of file management programs, loaders
for absolute binary (PAL output and core-image saves) and
relocatable binary (8K FORTRAN and SABR output), an
editor (Symbolic Editor for 4K or TECO-8 for 8K), and
an assembler (PAL-IV for 8K).

PDP-8 WORKSHOP

This discussion will deal with the file management programs which have the following properties:
1. System tape may be write-locked; all unit numbers
may be utilized for reading or writing files.

TS-8 MAG NETIC TAPE SYSTEM
Charles R. Conkling, Jr., Infotec, Inc.,
Plainview, New York

2. Files need not occupy consecutive blocks on tape,
and deleting a file does not disturb other files.

This paper describes the Infotec. Inc., TS-8 Magnetic Tape System. This system allows the user to
write and read IBM 7 Track Magnetic Tapes on the
DEC PDP-8 family of computers.

program interrupt.

5. File directories may be listed selectively; system
fi les are not listed.

Program Subroutines (IBM BCD 7 track)
1.
2.
3.

Read a b lock and store in Buffer area.
Write a block from Buffer area.
Tape Service (load Point, Rewind, Space).

TECO-8: TEXT EDITOR AND CORRECTOR PROGRAM
FOR THE PDP-8

B. Program Routines to Load Programs from Magnetic
Tape.
C.

I/o uses

4. Six character fi Ie names plus one character fi Ie
type identifiers may be reused without losing the
earl ier fi les.

It also describes the programs that will be submitted to
the DECUS Program Library. These programs are as
follows:
A.

System

Russell B. Ham, U.S. Public Health Service,
Winchester, Massachusetts

Fundamentals of a Magnetic Tape Operating System.

TECO is a sophisticated editor program which operates
on character strings rather than I ines of test. This version
is derived from the specifications for PDP-10 TECO with
the following additions:

ACCESSING DATA ARRAYS AND TELETYPE TEXT
INPUT/OUTPUT

1. Separate Iine-oriented and character-oriented
commands.

David G • Frutchey, Beckman Instruments, Inc.,
Fullerton, California

Two subroutine packages were developed during a
project regarding the measurement of the Acid-Base
Balance of Human Blood in a real-time system environment. When used with any of the standard Floating
Point Packages, these subroutines provide the user with
a powerful, yet concise, programming methodology. The
first subroutine package entitled "Array Accessing Subroutine Package" permits the user to access both fixed
and floating point data located anywhere in the first 2K
(K= 1024) words of core storage regard less of page overlap.
Both data storage and retrieval can be performed on terms
analogous to singly-subscripted FORTRAN array terms
such as "ARRAY(a* J±b)." The second subroutine package,
entitled "TTY TEXT I/o," provides a concise facility for
text output (63 characters), character input', line spacing
and page tabs. Application programming examples are
included.

A Replace command.

3. Commands to load a Q-register or produce output
directly.
4.

Extensive formatting of console Teleprinter output.

5. Abi Iity to specify sets of strings in a Search
command.
--6.

Provision for lower-case USASC II characters.

TECO-8 requires 8K or core and EAE; high speed reader
and punch are very desirable. DECtape I/o under
OS/8 (q.v.) is available from the author. All I/o is
buffered and uses program interrupt. Ten Q-registers
(aux i II iary text buffers or command macros) are provided.

Neurophysiological and statistical examples of appl ication
will be shown that are more compact and faster than
analogous programs written in PDP-8 FORTRAN.

A DISC ORIENTED REAL-TIME EXECUTIVE FOR
THE PDP-8/S COMPUTER
W. T. Lyon, ·Aluminum Company of America,
Pittsburgh, Pennsylvania

TSS/8: GENERAL PURPOSE TIME-SHARED PDP-8
This Executive was written to operate in a real-time
environment for process control.

Don Witcraft, Digital Equipment Corporation,
Maynard, Massachusetts

The original version of the program provides 12 levels
of priority. It allows for up to 115 separate programs
allocated to various priority levels. It decodes 24
process interrupts and provides 24 software timers.

This will be a presentation of the TSS/8 including:

In addition, the system has a keyboard mon itor to
perform such utility functions as binary punch and octal
dumps of core or disc. Restructuring of the system can
be accompl ished by reassembly.

phi losophy of design,

philosophy of implementation,

operational characteristics, and

I ibrary programs included under TSS/8.

A question period and demonstration will follow.
AUTOMATIC SUBROUTINE LINKAGE ACROSS
CORE BANKS IN A PDP-8
Joseph Rodnite, Information Control Systems,
San Francisco, California

PDP-6/10 WORKSHOP

The problems associated with automatic subroutine
linkage between core banks are manyfold. The basic
problem is that the machine word has 12 bits available
for an address and the addresses are greater than 1 2
bits. The algorithm presented is used in the implementation of the 8K FORTRAN compi ler. The problem is
approached from an assembly language level and extends
through the loader and resident operating system. An
understanding of the memory extension hardware is
necessary to fu Ily understand the a Igorithm presented.

SYNCHRONOUS COMMUNICATION INTERFACE
FOR THE PDP-10
Norman Housley, The University of Western Ontario,
London, Ontario, Canada
Most remote card reader/printer terminals (whether
computer or wired logic controlled) commercially
available utilize the synchronous communication method
of data transm iss ion . The PDP-10 hardware/software
presently does not support such devices. The University
computing center is committed to providing remote job
entry facil ities using card reader/printer terminals.
Data rates of up to 2400 bits per second (using the 201 B
data set) are contemplated.

TMF - A PROCEDURAL SOFTWARE PACKAGE FOR
BIOMEDICAL AND SCIENTIFIC APPLICATIONS
ON THE PDP-8
Fred R. Sias, Jr.*, and Allan B. Wilson, University
of Mississippi Medical Center, Jackson, Mississippi

A solution to this requirement is the use of additional
Teletype receiver/transmitter modules (DEC W-706/707)
as a front end to the PDP-10 data line scanner. The
present scheme uses two receivers and two transmitters
in addition to one scanner channel. This system gives
almost a full character time for the software to service
the synchronous line as opposed to the existing system
which allows approximately 1 1/2 bit times for servicing.

Programmers using high-level compilers such as FORTRAN
find the procedural capabilities of the language at least
as useful as the arithmetical features. While floating
point arithmetic software packages are usually provided
by computer manufacturers to ease the programming effort
when using assembly languages, analogous procedural
packages are usually not available.
TMF is a procedural software package including an
Input-Output Control System (IOCS-8) for use with the
PAL III or MACRO-8 assembly systems on the PDP-8 series
of machines. A number of definitions are added to the
permanent symbol table of each assembler to permit execution of procedural subroutines analogous to FORTRAN
statements such as IF, GOTO, DO, READ, WRITE, CALL,
and RETURN. A keyboard monitor and relocating loader
is included in the basic system.

RAPID PROGRAM GENERATION USING THE
DEC PDP-6/10 TIME-SHARING MONITOR
William F. Weiher, Stanford Artificial Intelligence
Laboratory, and Richard P. Gruen, Digital Equipment
Corporation, Palo Alto, Cal iforn ia
Rapid Program Generation on the PDP-6/10 has been
made possible by the addition of five commands to the

DEC Time-Sharing Mon itor. These commands (EXECUTE,
DEBUG, COMPILE, LOAD, and CREF) allow the
time-sharing user to specify the names of the programs
which he wishes to use and then delegate to the Rapid
Program Generation System the task of compiling,
assembl ing, and loading these programs, as needed,
without requiring the user to type CUSP commands. The
implementation makes use of an RPG cusp and some small
files on the disk; only nine additional instructions have
been added to the Time-Sharing Monitor.

new considerations. This paper will deal with three
major areas of concern: the economics of using M-series
vs. standard R-series, system design of I/o using T2L
logic for interfacing on-line control and data acquisition
experiments, and specific problems and solutions when
using the M-series line for an interface. (Including
special cards which have been designed.) A specific
data acquisition and control interface for a PDP-9 will
be used as an examp Ie of the three genera I areas above.

A DATA COMMUNICATION SYSTEM FOR THE
PDP-S IN ARBUS

MODULES/HARDWARE WORKSHOP

Thomas G. Taussig, Lawrence Radiation Laboratory,
University of California, Berkeley, California
A data communication interface developed for ARBUS
(Advanced Reservation and Bed Utilization Systempaper to be presented by R. Abbott, Biomedical Session)
wi II be described. The low cost, high speed data break
interface allows the connection of multiple duplex Teletype stations and data phones to the PDP-S. The design
of this system results in low program overhead requiring
less than 5 percent of computation time to assemble
characters from 32 lines, sampl ing at S times the 110
baud rate. The system requ ires 2 words of memory per
line.

PROGRAMMED MIXED MODE DATA COMMUNICATION
Hans J. Breme, Western Electric Company, Princeton,
New Jersey
An arrangement for data acqu isition by a PDP-S from
remote terminals such as IBM 2701, 7702, 1013, 7711
including the IIsync hronous Transmit Receive" mode
is shown. The problem of maintaining bit phase with
the starting record is overcome by modifying the DEC
DPOI A interface. The synchronization with varying
characters is programmed and uses the OR-buffer. Error
detection and correction is accompl ished via software
either in the ARQ or FEC mode. The PDP-S may communicate with several remote terminals simultaneously,
they need not be the same type.

FOCAL WORKSHOP
Rick Merrill, Digital Equipment Corporation,
Maynard, Massachusetts
The data structure of FOCAL, the use of certain
subroutines, and the creation of new functions will
be examined. Discussion will elaborate upon the
LIBRARY command, its uses, forms, and implementation
with the intention of final izing the design of Disk
FOCAL.

PDP-sis IBM 360/65 DATA LINK
Larry Green, Department of Psychology, University of
California, Santa Barbara, California
A PDP-sis is dedicated to collection of psychophysical
and behavioral data from several laboratories for transmission to an IBM 360/65. When massive computation is
required', paper tape data or converted analog data is
loaded into the S/S where a preprocessing routine determines
if the data merits analysis. If the data is valid, it is blocktransferred into the 360/65 for manipulation and display of
terminal data through the Culler-Fried Teleputer System.

LOCAL USERS GROUP

~lEETING

At Stanford University, a Stanford Local DECUS
Users Group (SLUG) has been orga':;-ized for the purpose
Of pooling DECUS software information in a local area
and bringing about a closer working relationship between the users of 35 or so various PDP-l's through
PDP-I0's on campus. Some of their initial objectives
are: to present to DEC, in a uniform manner, opinions
(good, bad, or indifferent) regarding DEC software;
and to create a central local source for information
exchange on software and hardware problems, as well
as latest changes in software and manuals.

System organization, interfacing hardware, and difficulties
encountered during development wi II be described.

RECENT EXPERIENCES IN DESIGNING MODULAR
INTERFACES USING M-SERIES LOGIC
Gary B. Morgan, Idaho Nuclear Corporation,
Idaho Falls, Idaho

The University of California, Berkeley Campus and
Lawrence Radiation Laboratory at Berkeley and
Livermore have also formed such a group for the same
purposes. During this meeting, they will present what
has been done and discuss the va lue of LUG IS.

The use of M-series (T2L integrated circuit logic)
modules for interfacing to computers which are constructed using Band R series modu les involves some

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