UNIVAC 490 Operating and maintenance instructions

o
GENERAL DESCRIPTION. .
f:he UNIVAC ® 490
Real-Time Sysf:em
•

GENERAL DESCRIPTION
UNIVAC 490
Real-Time Sys-tem
© 1961 • SPERRY RAND CORPORATION

Contents
1. UNIVAC 490 REAL-TIME SYSTEM
The Real-Time Concept. ............ ........................................... . 1
General Characteristics of
the Real-Time System.................... . ...... ... .. 2
High-Speed Communications
Linkage........................................... 2
Data Storage
Facilities. . . . . . . .. . . .. . . . . . .. . . . . . . . . . . .. . . . . .. . . . . .. . . . . . . . .. . . . . . 2
Features
and Applications ...................................................... 2
Processing
Interrupt..... .......... .. ....... . .. .. .. .. ... ...... .. . .... .. .. . . .. 2
Solid-State Design
........................................................... 3
Computer-to-Computer
Configurations....................................... 3
High-Speed Random Access
Storage.................... ... ............... ... 3
A "Time Conscious" System
................................................. 3
Incremental
Clock...................................................... ..... 3
Incremental Interrupt
Clock........................... ............ ...... ..... 3
Day
Clock................................................................... 3
High Internal Computing Speeds........................................... .. 4
Equipment
Enclosure..................................................... ... 4
Flexible Input-Output
Facilities.......................................... ..... 4
Automatic Programming
..................................................... 4
Floating-Point Arithmetic
.................................................... 4
Programming
Checks......................... ............................ ... 4
Special Programming
Features.............................................. .... 5
Powerful Instruction
Repertoire.............................................. 5
Absolute Efficiency
.......................................................... 5
Library of Programmed
Routines............................................. 5
Core Storage Search
......................................................... 5
Wired
Memory. . . . . .. . . . . . . . . .. .. . . . . . . .. . . . . . . . . . . . .. . . . . . .. . . . .. . . . . . . . . .. . 5
Application Versatility
....................................................... 6
2. REAL-TIME COMPUTER
Storage Section ................................................................. 7
Octal Notation. . . . . . . .. . . . . .. . . . . .. . . . . .. . . . . . . . . . . . . . .. . . . .. . . . . .. . . . . .. . . . . 7
Control Section
................................................................. 8
Arithmetic
Section..... .................................. ....................... 8
Arithmetic Registers (Operational Registers)
................................. 9
Transient Registers
.......................................................... 10
Operator Console ............................................................... 11
Computer Control Panel
..................................................... 11
Console Keyboard and Printer
............................................... 11
Wired
Memory. . . . . . . .. . . . . . . .. . . .. . . . . .. . . . . . . . . . .. . . . . . . . . . . .. . . . .. . . . . . . .. 11

3. SYSTEM COMPONENTS AND CONFiGURATiONS
Central Site Equipment ...................................................•..... 12
Peripheral Units............................................................. 12
Peripheral Systems ..........................•.•............................. 12
Magnetic Drum Storage .......................................•.....•........ 14
Magnetic Tape Storage ...•..............••.................................. 15
High-Speed Card Reader... . . .. . . . . . . . . . . .. . . . . .. . . •. . .. .. . .. . .. . .. . .. . .. . . .. 16
Punch-Verifier Unit ......•.........•..........................•.............. 16
High-Speed Printer ............•............................................. 17
Transmission and Communications .....................................•....... 18
Input-Output Channels ...............................•.....•................. 18
Data Transfers ............................•...................•............. 18
Buffer Mode. . . .. . . . . . .. . . . . . .. . . . . . •. . . . . . . . .. . .. . . . . .. . . . . . . . . . . . . . .. . . . . .. 18
I nput-Output Control ..........................••............................ 18
External Equipment Requirements ........................................... 19
Remote Input-Output Devices ..........................................•........ 19
Keyboard Printer ..........•...............•................................. 19
Uniset Console ......•...........••.................•........................ 20
The Uniset .................................................................• 21
Format Control Panel ..........•... '. . . .. . . . . . . .•. . .. . . . .. . . . . . •. . .. . . . . . . . . .. 21
Communications Equipment ......................•............................. 21
Communications Systems ...................................................... 23
Party Line Network ............................................................. , 23
Scanner -Selector
..................•...............•.........•.............. 23
Party Line Communications System ............................................. 23
Transfer Function ...............................................•...•....... 24
Line Switching Network (Direct Distance Dialing) ..............................•. 24
Communications Control Unit (Telegraphic Half-Duplex) ........................ 24
Communications Equipment for Special Devices ................................. 26
4. INSTRUCTIONS
Instruction Word ............................................................... 27
Instruction Cycle ...................................................•........... 27
Instruction Repertoire.......................................................... 28
Shift Instructions ............ , ............ " .................... '" ............. 28
Simple Read Instructions ....................................................... 29
Store Instructions .............................................................. 29
Arithmetic Read Instructions .................................................... 30
Comparison Instructions ........................................................ 30
Selective Instructions ...................................•....................... 31
Replace
Instructions ............................................................ 31
Jump Instructions .............................................................. 32
Special Program - Modifying Instructions ..•.............•....................... 33

just as feedback is used by a computer
to control a missile's path;: ....
• •• up-to-the-minute data from
a UNIVAC Real-Time System can help
influence the course of business curves.

1. UNIVAC 490 Real-Time System
The UNIV AC®490 Real-Time System is a
large-scale,
general purpose digital com-
puting system specifically designed for the
dynamic organization which has diverse
operations demanding stricter control
based on real-time computing. This new
system extends valuable techniques of real-
tinle processing, long restricted to a linlited
number of special military applications
such as missile guidance, to the broader
field of commercial problems.
Remington Rand's installation of UNIVAC
Airlines Reservation Systems at several
major airlines demonstrated the power of
real-time processing. A centrally located
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formation in a fraction of a second to ticket
offices scattered throughout the country.
The well-documented success of the Airline
Reservations System proved the potential
of real-time processing and served as the
incentive for its full development.
Now,
with the Real-Time System, the full
commercial
potential of real-time process-
ing can become an integral part of your
business, bringing with it an efficiency and
control only approximated by other devices.
In fact, just as feedback is used by a com-
puter to control a missile's path and coun-
teract disrupting forces, up-to-the-minute
data from a real-time system can help an
organization influence the course of a
number of its business curves as they are
formed.
THE REAL-TIME CONCEPT
The real-time concept is the fulfillment of
management's desire for a method of re-
versing the direction of a business curve
before it gains momentum and attains
black-and-white finality. Up-to-the-minute
indications of business activity enable the
real-time user to detect the suggestion of a
downturn and correct it immediately, in
much the same way as a guided missile's
course is
adj usted as it hurtles to its target.
If, for example, sales have dipped slightly,
the Real-Time Computer will allow man-
agement to discover this fact immediately,
instead of waiting for quarterly reports. As
a result, management's remedial actions
are effectively timed. And it is the timely
decision which has the greatest significance
in the intensified competition of business
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organizational activities, it is necessary to
utilize a real-time processing system, with
its ability to communicate with many
remote locations and its large storage fa-
cilities, to reflect sales, profits, costs, pro-
duction, and other pertinent data.
Thus, the real-time concept is a significant
advance in data-processing, a field which
heretofore employed batch processing only.
That is, master data, or information which
is altered infrequently or in a known man-
ner, was updated at intervals, upon the ac-
cumulation of enough transaction data, or
information characterized by essentially
random and unpredictable incidence. Real-
time processing, however, eliminates the
lag between the occurrence of transactions
and their postings to a master file. By up-
dating the master file immediately upon
receipt of a new transaction from a remote
source, the Real-Time System can present
a truly current report of the status of any
1

2
application-a feat impossible for the batch-
processing computer
with its externally
stored master data.
GENERAL CHARACTERISTICS OF THE
REAL-TIME SYSTEM
The specific design and function of the re-
mote
input-output units of the UNIVAC
490 Real-Time System
are dictated by the
nature of the individual application. In
general, however, input units are able to
accept transaction data with speed and
reliability while the output units display
results
with accuracy and clarity. The com-
puting unit of the system is general pur-
pose, and therefore, ideal for all types of
applications.
High-Speed Communications Linkage
Common carriers, such as American Tele-
phone and Telegraph, Western Union,
American Cable and Radio, afford high-
speed communicationfacilities
for two-way
transmission of data between the central
site Computer and the remote input-output
units. Transactions originating at remote
points
are conveyed along these wires di-
rectly to
the Computer where they are im-
mediately evaluated
and processed. Then
the result is returned to the originator and
other appropriate distant points, the whole
transaction being accomplished in seconds.
Data Storage Facilities
Since the UNIVAC 490 Real-Time System
applies
transaction data to the master file
information as the transaction data occurs,
the system employs extensive data-storage
facilities which are capable of storing en-
tire master files of information. In addition,
these facilities
are of the random access
type allowing immediate access to master
file information.
FEATURES AND APPLICATIONS
In addition to existing applications best
performed by this system, there is a grow-
ing number of vital data-processing prob-
lems
that depend on this type of automation
-the UNIVAC 490 Real-Time System-for
their effective solution.
The many outstanding features of the
UNIV AC 490 Real-Time System are par-
ticularly suited to applications in which
processing timeliness is vitally
important,
perishabilityis a factor, or decision-making
is based on
data originating simultaneously
at separate, remote points. Some of these
features, such as solid-state components
and microsecond internal computing
speeds~ represent the latest design advances
in the electronic computer field. Other fea-
tures of the system, such as the ability to
communicate with remote locations and to
perform both real-time and batch-process-
ing applications, are entirely new develop-
ments.
Some
of the major features of the UNIVAC
490 Real-Time System
are described briefly
in the following paragraphs.
Processing Interrupt
An outstanding feature of the UNIVAC
490 Real-Time
System is its capacity to
process real-time and batch-processing
applications concurrently. This impressive
data-processing innovation is made possi-
ble
through a unique feature that permits
remote external units to interrupt Com-
puter processing with information of high
precedence.
With this feature the maximum process-
ing potential of the system is realized. For
example, when once the master data for a
particular real-time application is recorded
in storage, the Computer can be used to
process a
"batch" application. Then, when-
ever transaction data for the real-time
problem is entered into a remote external
unit, the Computer's batch-processing is
interrupted to permit handling the high
priority real-time transaction and sending
the processed results to the external unit.
Upon completion
of the real-time process-
ing,
the Computer automatically returns to
the batch application. Further, if the real-
time
information handled during the inter-
rupt bears on the interrupted application,
the latter can be updated by the real-time
data,
thereby assuring that all subsequent
processing is up
to date.

Sol id-State Design
The solid-state components and circuitry of
the UNIVAC 490 Real-Time System offer
numerous
advantages including standard-
ized production of components and the re-
duction
of maintenance procedures to a few
relatively simple operations.
In addition to
ease
of production and maintenance, solid-
state circuits also impart a high degree of
operating reliability to the Computer while
reducing
the power, cooling, and space re-
quirements
of the system.
Computer-to-Computer Configurations
The UNIVAC 490 Real-Time System's abil-
ity to coordinate, through communication
networks,
the activities of several Com-
puters located at various points, allows the
user to increase his data-processing system
to meet
any sudden business expansion.
High-Speed Random Access Storage
To meet the extremely demanding require-
ments of real-time processing, the
UNIVAC 490Real-TimeSystemisequipped
with data-storage facilities (drums, tapes)
that are more expansive and versatile than
those of most present-day computing sys-
tems. The Computer has an internal co:re
memory with a capacity of 32,768 or 16,384
30-bit words.
A "Time Conscious" System
Processing timeliness, an inherent charac-
teristic of real-time processing, requires
the system to be extremely "time con-
scious." Three precision electronic chro-
nometers provide
the system with a timing
sensitivity unmatched by other computing
systems.
Incremental Clock
Thisbuilt-in clock is used for a wide variety
of program-timing purposes. It can be used
to log
the receipt times of aperiodic real-
time
input data. Each input message and
its receipt time may be recorded together.
This clock is also used
in connection with
the preparation of statistical and analyt-
ical reports dealing with the frequency of
certain transactions.
Incremental-Interrupt Clock
This "program-set" clock counts up to
32,768 milliseconds. Upon reaching its up-
per limit, the Incremental-Interrupt Clock
unconditionally interrupts the Computer at
the end of the instruction being handled,
regardless of the type of instruction. The
clock count is maintained in core storage.
The Incremental-Interrupt Clock is vital to
the functioning of a real-time system be-
cause one
of the primary uses of this clock
is
timing subroutine operations. If a mo-
mentary fault arising from improper pro-
gramming throws the Computer into a
closed loop,
or if a fault occurring during
the execution of an instruction halts the
Computer, the Incremental-Interrupt Clock
restarts the Computer by means of an in-
terrupt, thus providing automatic fault
recovery. The interrupt can be used to no-
tify maintenance personnel that a closed
loop
has occurred. If completing an opera-
tion takes longer than desired, this clock is
also used to
interrupt the Computer and
thereby allow program attention to be di-
rected
to items of more immediate impor-
tance.
Day Clock
A feature particularly suited to real-time
problems is
the 24-hour Day Clock. As an
auxiliary device, this electronicclockcauses
an external interrupt of Computer process-
ing once every minute. Thus, "keeping
time" is placed completely under the pro ..
grammer's direction.
Since
program control is shifted once every
minute to a set address in the Computer,
the Day Clock can be used to initiate a va-
riety of subroutines. For example, by using
a compare routine on the address reserved
for timing purposes, reports can be gener-
ated at any desired time of the day, week or
month. These reports could provide up-to-
the-minute
information and analyses of
company status. Error-checking routines,
trace routines, output conversions, manage-
ment report programs, maintenance rou-
tines,
and memory dumps are some of the
many routines which can be initiated by
the Day Clock.
3

4
High-Internal Computing Speeds
Along with its high-speed random access
storage facilities, which allow a high data-
transmission rate between the Computer
and peripheral units, the UNIVAC 490
Real- Time System also features instruction
execution times measured in microseconds.
Instruction access and execution time totals
12 microseconds for most instructions.
Equipment Enclosure
The physical arrangement of the Computer,
its peripheral units, and the operator's con-
trol panel demonstrate the UNIVAC 490
Real-Time System's revolutionary equip-
ment enclosureconcept. This modern equip-
ment installation technique affords the
operator an unrestricted view of all signifi-
cant indicators and displays. It also posi-
tions
the peripheral units within easy reach
to allow the operator to attend to them
when necessary.
Maintenance personnel, located outside
the
operator's enclosure, have unrestricted ac-
cess to all equipment even though it is in
operation. Any element of the system may
be monitored for maintenance without in-
terfering with operating personnel.
In terms of economy of installation, the
equipment enclosure design concept pre-
sents the additional advantages of greatly
reducing floor-space requirements and
eliminating the need for expensive false
floors.
Flexible Input-Output Facilities
The UNIVAC 490 Real-Time System can
communicate directly with a wide variety
of commercially available input-output
units and custom-designed data-originating
devices. The system's Computer is also
capable of communicating directly with
other computers. The inherent flexibility
of the system's input-output channels en-
ables the UNIVAC 490 Real-Time Com-
puter to perform this diversity of input-
output data communicating functions.
A
large number of system input-output
channels are employed for communications
between
the Computer and peripheral site
units such as high-speed printers, mass-
storage units, card readers, and tape-han-
dling units. These same channels
can be
used to accommodate
an almost unlimited
number of remote data-originating devices
by
using a special input-output buffermode.
Two
input-output channels are utilized for
communications between the UNIVAC 490
Real-Time Computer and other computers.
Automatic Programming
The system features a very flexible compil-
ing system which allows mnemonic expres-
sion
of computer-oriented instructions. In-
structions and addresses to which they
refer can be given alpha-numeric names.
Program check-out can be accomplished
with special aids which include post mor-
tem and register dumping routines. A sub-
routine mechanism facilities compilation
of subroutines into a final program. The
compiling system also has a high-level,
problem-oriented language in which com-
puter programs are written. This compiler
interprets general statements and auto-
matically generates the necessary machine
instructions which perform the stated
function.
Floating-Point Arithmetic
The UNIVAC 490 Real-Time Computer
floating-point format is based on a two-
program-word information unit, one man-
tissa and one characteristic word. The
length of the mantissa is' 28 bits, and the
length of the characteristic is 15 bits, in-
cluding a sign. It is a three-address system
in which four index-registers are used to
designate the operand and the function
codes. As a complete
software system, it
includes input-output conversion and func-
tion evaluation.
Programming Checks
An important characteristic of the
UNIVAC 490 Real-Time System is operat-

ing reliability, a mandatory requirement of
a system designed for real-time processing.
Although the system's reliability is
achieved through solid-state components, a
number of progran1 checks and error-de-
tection procedures also contribute to the
system's highly reliable performance. The
system features a routine for automatic
restarting after an error is detected and
corrected. Because transaction data in real-
time applications is usually independent
and unrelated to previously entered infor-
mation, the system provides a routine that
preserves the transaction data being proc-
essed should
an error occur.
SPECIAL PROGRAMMING FEATURES
Special programming features enable the
UNIVAC 490 Real-Time System to process
virtually any type of commercial or scien-
tific
data-processing application. In addi-
tion to latest engineering advances incor-
porated into the logic of the system, a host
of special software programming features
associated with the system allows the user
to cut programming costs to a minimum.
Powerful Instruction Repertoire
The sixty-two function code values in the
instruction repertoire can be modified by
the system to provide unlimited program-
ming versatility. Much of the real program-
ming power of the computer lies in the
unique format of the instruction word. Of
the thirty bit positions in the instruction
word, nine serve as special purpose desig-
nators. When these designators are used in
combination with the function codes, the
computer can perform more than 25,000
basic programming operations.
Absolute Efficiency
Execution of a stored program of instruc-
tions on the Real-Time Computer proceeds
in a series of steps. Very often, however,
the unique requirements of real-time prob-
lems necessitate programming a large num-
ber of jump and skip operations. The prev-
alence of these operations arises because
the processing activities of a real-time com-
puter involve serving a large number of
remote peripheral units that are constantly
demanding computer attention on an im-
mediate or near-immediate basis.
Since skip and jump programming opera-
tions are inherent in real-time processing,
the internal logic of the UNIVAC 490 Real-
Time Computer causes these operations to
be handled in a manner approaching abso-
lute efficiency. For example, because the
next instruction is in "review" while the
current instruction is being executed, a skip
instruction brings the computer-at no loss
of time-directly to the resumption point
without leafing through intervening in-
structions. Jump instructions are processed
by the computer with similar efficiency.
Library of Programmed Routines
A maj or problem often encountered in the
installation of a new type of computing sys-
tem is the large amount of programming
required to put the system in operation.
Because the UNIVAC 490 Real-Time Sys-
tem evolved from prototype systems which
are now performing successfully at com-
mercial,
government, and military installa-
tions, an extensive library of proven pro-
gramming routines, including compiler and
assembly systems, is available to the user
immediately.
Core Storage Search
From a programming standpoint, a very
desirable and practical provision of the
UNIVAC 490 Real-Time System is the fea-
ture which allows the entire core storage, or
selected portions of it, to be searched auto-
matically and rapidly. Programming the
search operation requires the use of only
two instructions.
Wired Memory
A permanent memory is built into the Com-
puter for program input and automatic
error recovery. It consists of sixteen 30-bit
words of storage, and is wired to fit the
specialized needs of the Computer user.
This storage may be accessed by a program,
but can only be changed manually.
5

6
Application Versatility
Designed primarily for real-time applica-
tions, this system can effectively handle
numerous commercial and scientific batch-
processing applications. Yet
it is the real-
time function
of the system that brings a
significant new dimension to electronic
data-processing-fingertip access to a pow-
erful computer from
man.y remote points.
The ability to consult vast quantities
of
updated files in a random manner with im-
mediate program response makes this sys-
tem ideal whenever an application hinges
on
exacting time requirements. Thus,
whenever time is of great importance as it
is where perishability is involved or where
customer service must
be rapid or where
ACCOU~TS RECEIVABLE
CHARGE ACCOU~TS
information from several sources must be
interrelated for subsequent operations, the
UNIVAC 490 Real-Time System can handle
the application more effectively than any
other system. For example,
if a warehouse
can make known the availability and quan-
tity
of its perishable goods, the points of
sale can order their full requirements. In
the area
of production, to cite another
example, work-in-process control can be
carefully followed and interim cost figures
developed to determine the desirability
of
alternate methods of production, as well as
optimum manufacturing quantities. The
UNIVAC 490 Real-Time System, then, has
been conceived for use on an unlimited va-
riety
of applications. Figure 1-1 shows
some real-time data-processing areas listed
by industry and application.
I~TERLINE RECEIVABLE I
PAYABLES
-tttJt-+-ti.-+--+---t--+--+---t--I--+---1--I--4---1--I--4---1f--I--+--If---I--
SAVINGS ACCOUNTS ,--+-+-+--+-+-+--+-+-+--+-+-I--+--1HJ"'~-I---I--.J--I---'--.J--I-..,
CHECKI~G ACCOUNTS t---t--+--+---t--+--+---t--+--+---t--f--+-.-.!~-I--4--If--I--+--If--I--+--II-"""
STOCK TRANSFER +----It--+-+--1I--+-+--1I--+-+-I--+--1RJ~ .. H __ +-J_-I---I--J_-+--I--.J__I_
MORTGAGE +-+--+-+-+--;-+-+--;-+-+--;I-+-IA~~IHI-4---I-4--4-~I-4--+---1f-
COST ACCUMULATION --i~-f--+-4ir.-f--+--IHI+lHt+IIHI--f--IFRI~~-+--I--II--+-IQ:lhl--+--I--I--+--I-
SPACE CONTROL -+-ti~EB ... ye.+-+---+-+-+---+-+--I---1--+--I---I--+-I=a:a4l:a..-I--tg--lI--I--
RESERVATIONS --I--II+IIHI ~-.tH)"~-t-+-I--t-+-I---J--I--.J---J--I---I-...4--I---I---1--I--~--1-
RAW MATERIAL -+-+-+--+-+-+-ti"'EBt-+---+-+-I:B--J-+--I--I---+ __ m-l--+-+---1--I--",-
SEMI-FINISHEO GOODS -t--+---1--t--+---IH~
FINISHED GOODS ..... -01-4--1--01-.-+
STOR ES SU PPL IE S +-.&IIao4~t4I~ 104-.+l..-+- .....
SCHEDULING MACHINES '-~ __ +"'''4--I-'''''''' ~~I---+--I-~""-+--I-~I---+-II~
SCHEDULING MANPOWER -4m.cIlG~m~~"l4m"'D-I-+-4D-I-+--I----1--l-"'~41~m~-l-.II~Ift!~
AIRLINE
SHIP
RAIL
HOTEL-CHAIN
DISTRIBUTION
MANUFACTURE
PROCESS
DEPARTMENT STORE
CHAIN STORE
MAIL ORDER
UTILITY
FAA
PETROLEUM
CREDIT CARD
LOAN ASSOCIATION
SAVINGS BANK
COMMERCIAL BANK
BROKERAGE
Figure 1-1. Real-Time Data-Processing- Applications
COMMUNICA T IONS
MILITARY
GOVERMENT NO~-FEDERAL
GOVERMENT FEDERAL

The Computer in the UNIVAC 490 Real-
Time System is a stored program computer
designed for processing large quantities of
data on a real-time basis. The Computer has
large internal magnetic core storage, great
programming flexibility, and a versatile
input-output section.
The Computer forms the heart of any
UNIVAC 490 Real-Time System. Its solid-
state arithmetic and logical circuitry per-
form tens of thousands of processing
operations every second, in both batch-
processing and real-time modes.
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Time Computer are listed below:
• Access time to all core storage locations of 1.9
microseconds; ability to store and to select in-
formation randomly
• 30-bit word length with a I5-bit half-word option
• Repertoire of 62 basic instructions which can be
modified to produce over 25,000 different instruc-
tions
• Single address instructions with provision for
address modification
• Multiple program capabilities
• Ability to perform rapid data exchanges with ex-
ternal equipment without main program attention
• Real-time clock for automatically initiating various
Computer operations at predetermined times
• Parallel one's complement binary notation
2. Real-Time Computer
STORAGE SECTION
Internal storage of the Computer consists
of banks of ferrite cores. Thousands of
these cores can be mounted within a square
printed-circuit frame. Each core is capable
of assuming either of two stable magnetic
states: one represents binary zero; the
other, binary one.
At the option of the user, magnetic core
storage is available in banks of 16,384 or
32,768 computer words. Access to informa-
tion in core storage is random since it is
independent of the address selected. Words
can be inserted into or removed from any
address in core storage at a rate of six
microseconds per word. Figure 2-1 shows
the basic internal data word.
Octal Notation
Although the UNIVAC 490 Real-Time
Computer is a binary computer, the prob-
lem of converting large decimal numbers
into binary notation sometimes becomes
cumbersome.
For this reason, binary nota-
tion is expressed in what is known as octal
form.
The conversion from binary to octal
notation simply involves dividing the bi-
nary digits into consecutive sets of three
from right to left, and then reading these
sets in decimal. For example, a full core
storage system requires the use of 32,768
storage addresses. Representation of the
upper limit storage address in binary nota-
iiiiiilllllllllllill
Figure 2-1. Basic Internal Data Word
7

8
tion requires the use of 15 bits. This same
decimal number, however, can be repre-
sented by five octal digits.
Decimal
Binary
Octal
32,767
111 111 111 111 111
77777
It should be noted that the working digits
in the octal system are 0 through 7. The
word octal means eight; therefore, when
counting in octal notation, the number after
seven is ten. In the Real-Time Computer,
the function code values, the operand ad-
dress, and the operand itself (when the 15-
bit option is used) are expressed in octal
notation.
MAIN MEMORY
16K. 32K MAGNETIC CORE
CO REGISTER
INPUT
GATES
Cl REGISTER
i!·REGISTER
CONTROL SECTION
In addition to the magnetic core storage
section, the Computer has two other sec-
tions, arithmetic and control (Figure 2-2).
The control section is responsible for the
operations that take place during the se-
quential execution of instructions. It also
coordinates the flow of data between the
arithmetic and storage sections.
ARITHMETIC SECTION
The arithmetic section is composed of the
circuits and registers used to perform
arithmetic and logical operations. These
operations are performed in a parallel bi-
PROGRAM CONTROL
U·REGISTER
P·REGISTER
S-REGISTER
A·REGISTER
ARITHMETIC CONTROL I~-------t----------- ......
Q-REGISTER
X·REGISTER
D·REGISTER
ADDER
Fig'ure 2-2. Simplified Logical Diagram of the UNIVAC Real-Time Computer

nary mode. The arithmetic mode is one's
complement
subtractive.
The high internal computing speeds of the
Computer allow arithmetic operations to
be carried out at microsecond speeds. For
example, additions and subtractions are
performed in a maximum of 12 microsec-
onds.
The ability of the computer to per-
form arithmetic operations simultaneously
with input-output data transfers makes it
ideally suited to the processing of real-time
problems.
The UNIVAC 490 Real-Time Computer
contains a number of registers which holds
data during computation. These registers
are designated by a letter or letter-nu-
meral combination, and they are intercon-
nected by parallel transmission paths
through which information flows during
processing.
They fall into two categories: operational
and transient. Operational registers con-
tain information from one instruction to
another and are referred to in the opera-
tional description of each instruction. Tran-
sient registers, on the other hand, are tem-
porary storage locations that are always
cleared at the end of an instruction.
Arithmetic Registers (Operational Registers)
A-Register
The A-Register or Accumulator is the prin-
cipal 30-bit arithmetic register. It has
adding and shifting properties. In most
arithmetic operations, the result is retained
in register A for use in later program steps.
For example, after addition or subtraction,
the sum or difference remains in the accu-
mulator; after multiplication the most sig-
nificant
half of the product is gathered in
the accumulator; after division, the re-
mainder is left there.
The contents of register A may be shifted
right or left, as described in the instruction
repertoire. Left shifts are circular or cyclic,
and in a right shift the sign bit is extended
by the number of bit positions shifted and
the lower order digits are discarded.
Q-Register
The Q-Register is a 30-bit auxiliary arith-
metic register. Its principal function is to
assist the A-Register in multiply, divide,
and logical operations. Register Q has shift-
ing and logical properties, and performs
adding or counting functions as well.
The contents of the Q-Register may be
shifted right or left, in the same manner as
the contents of the A-Register.As shown in
Figure 2-2 all communication with the
Q-Register is through the X-Register.
Logical multiplication is performed on a
transmission path between the Q- and
X-Registers.
A- and Q-Registers In Combination
Certain instructions shift the contents of
the A- and Q-Registers as a single 60-bit
register, with the A-Register representing
the most significant half of the double-
length quantity. To illustrate, the Q-Regis-
ter holds the multiplier at the beginning of
a multiply operation. As the product is
formed, by repeated additions and shifts,
the multiplier digits are shifted to the right
and diseardedo In their plaee, the lower
order digits of the double-length product
are shifted into the Q-Register from the
accumulator.
During a divide operation, a process essen-
tially the reverse of multiplication takes
place. The double-length dividend is shifted
to the left, and the quotient bits are inserted
in the rightmost position of the Q-Register.
At the end of the divide sequence, the quo-
tient is assembled in the Q-Register,and the
remainder is left in the accumulator.
P-Register
The P-Register (15-bits) is the Program
Address Counter. This register holds the
address of the next sequential instruction
throughout the program. As each program
address is transferred from the P-Register
to the S-Register, the contents of the
P-Register are increased by one. When
Jump instructions are executed, the P-Reg-
ister is cleared and a new program address
is entered.
9

10
B-Register
The B-Registers (15-bits each) are Address-
Modifying Registers generally used for in-
dexing minor loops in a program. The con-
tents of one register may be used to incre-
ment the operand address before execution
of an instruction. Seven such registers are
provided and labeled Bl through B7. The B7
register also serves as a counter in the re-
peat mode where a selected instruction is
executed the number of times specified
(covered
later in instruction 70).
Transient Registers
The following registers are used in the
manipulation of instruction words and data
words during the execution of an instruc-
tion. These registers are not referenced in
the description of the instructions and do
not retain information from one operation
to the next.
X-Register
The X-Register (30-bits) functions as an
arithmetic communication register. It has
complementing, but not shifting, proper-
ties. The X-Register receives the operand
from storage during all arithmetic opera-
tions. All communication between the A-
and Q-Registers and the rest of the opera-
tional registers or the adder output is via
the X-Register.
K-Register
The K-Register (6-bits) functions as a
shift counter for all arithmetic operations
involving shifts. The maximum shift count
permitted is 60. Multiply and divide opera-
tions are controlled by presetting the
K-Register to 30. The K-Register then
counts the operational steps.
S-Register
The S-Register (15-bits) holds the storage
address during memory references. At the
beginning of a storage access period, the
address is transferred to the S-Register.
The contents of the S-Register are then
translated to activate the storage selection
system.
Z-Register
The Z-Register (30-bits) serves as an Oper-
and Buffer for storage references. During
the read portion of the storage access
period, the Z-Register is cleared. The digit-
reading amplifiers are then sampled to set
the contents of Z corresponding to bits in
the storage. During the write portion of
the stol'age access period, the Z-Register
controls
the inhibit circuits in order to
write or restore the disturbed storage reg-
ister. Input data is gated directly to the
Z-Register.
V-Register
The V-Register (30-bits) is the Program
Control Register. In other words, it holds
the instruction word during the execution
of an operation. The operation code and the
various execution modifiers are translated
from appropriate sections of this register.
If an address modification is required be-
fore execution, the contents of the appro-
priate B-Register are added to the contents
of the low order I5-bits of the V-Register.
R-Registwr
The R-Register (15-bits) functions as a
communications
register for all internal
transmissions to the B-Registers.
R1-Register
The RI-Register (15-bits) functions as a
communication
register for all internal
transmission from the B-Registers. It holds
the incrementing quantity during address
modification.
D-Register
The D-Register (30-bits) is the Arithmetic
Register which holds the operand, for pres-
entation to the adder, during the execution
of arithmetic operations.
C-Registe1'
The C-Registers are communication buffer
registers through which computer output
data are synchronized. There are two
C-Registers, Co and Cl. Co is used to com-

municate output data to peripheral devices
on 12
different channels. Cl is used to com-
municate output data on two different chan-
nels to other computers. Input data is gated
directly to the Z-Register.
OPERATOR CONSOLE
The UNIVAC 490 Real-Time Computer is
equipped
with a console that includes con-
trols that allow varied manually governed
operations including special modes~ Incre-
mental Clock Interrupt Disable Switch,
Programmed Jump Switches, and the Wired
:Memory Switch.
The two-way Wired MemorySwitch,located
on
the operator console, is marked "start"
and "neutral."
Computer Control Panel
Registers found on the maintenance panel include
the following:
1. Co-REGISTER
2. C1-REGISTER
3. Q-REGISTER
4. A-REGISTER
5. B1-REGISTER
6. B2-REGISTER
7. Ba-REGISTER
8. B4-REGISTER
9_ Bs-REGISTER
10. B6-REGISTER
11. B7-REGISTER
12. U-REGISTER
13. S-REGISTER
14_ P-REGISTER
Manual controls are provided on the Computer Con-
trol Panel which allow:
1. The execution of consecutive program steps at
a low rate.
2.
The execution of one consecutive Computer
clock phase (1,4 of a cycle) for each depression
of a switch.
3. The execution
of one consecutive program step
for each depression of a switch.
4. Operation
that is normal except that the Com-
puter does not stop when it executes a pro-
grammed stop instruction.
5. The Day Clock to be disconnected.
6. The
Increment Clock to be disconnected.
7. The
automatic recovery feature to be discon-
nected.
Because of their use in programming opera-
tions, some of the indicators and manual
controls listed above are duplicated on the
operator's console.
Console Keyboard and Printer
Located at the Computer Console, the Con-
sole Keyboard will normally be usable: dur-
ing program debugging, while making
changes to programs, schedules, or tables;
when initiating type-outs of interest to the
operators or UNIVAC Center supervisory
personnel; and in controlling the system.
There are no restrictions as to the size of
the units of information entered by this de-
vice,
orof the type-outs, so long as computer
formats are used and program provision
is made.
Wired Memory
As mentioned earlier the purpose of the
wired memory is to provide automatic
reading of new programs into the Compu-
ter with protection against erasing vital
instructions in the wired memory. The
wired addresses parallel the first 16 core
storage addresses (00-17, octal). Whether
the Computer operates with words in wired
or core, depends on the position of the
3-way Wired Memory Switch on the
Computer Control Panel and the two-way
switch on the Operator Console.
The positions of this switch are:
1. Automatic Recovery
2. Neutral
3. Bootstrap
When the Computer is on -and the Wired
Memory Switch is turned to Bootstrap, the
Computer starts the wired program in the
wired memory at address 00. During the
normal operation of the Computer, any
reference to the address between 00 and 17
(octal)
refers to the address in the wired
memory.
When the switch is in Automatic Recovery,
and a fault interrupt occurs, the Computer
will perform the program as wired in the
Wired Memory starting at address 14. A
fault interrupt is caused when an Incre-
mental Clock Interrupt or millisecond time-
out or an illegal function (00 or 77) occurs.
A millisecond
time-out occurs when, for
some reason, the Incremental Clock was
not updated. All other references to ad-
dresses between 00 and 17 (octal) refer
to words in core storage.
When the switch is in Neutral, the Compu-
ter ignores the wired memory and uses
address 00 through 17 (octal) in core
storage.
11

12
3. System Components
and Configurations
The individual components which combine
to
form a particular UNIV AC Real-Time
System configuration
vary in number and
type according to the application. Each
component of a UNIVAC Real-Time Sys-
tem, however, falls into one
of the following
categories:
1. Remote Inquiry-Answering Devices
2_ Communications Equipment
3. Central Site Equipment
Remote inquiry-answering devices situated
at many different locations have access to
the Computer and other central site equip-
ment through communications equipment.
Conversely, the same communications
equipment provides the central site units
with access to the remote units.
The communications equipment is divided
between
the remote inquiry-answering de-
vices
and the central site equipment. In ac-
tual operation, input information is entered
at a remote inquiry-answering device which
activates communications equipment
at the
same location. The information is trans-
mitted via communications lines to commu-
nications equipment
at the central site
where it is fed into the Computer for proc-
essing.
Output information emanating from
the Computer is fed through the communi-
cations equipment
to the proper inquiry-
answering device at a remote location.
CENTRAL SITE EQUIPMENT
Central site equipment used with a
UNIV AC Real-Time System includes a
Real-Time Computer, various
peripheral
units such as card readers, storage units,
and magnetic tape units, and communica-
tions equipment. Using
master data main-
tained at the central site, the Computer and
its peripheral units process all information
received from input-output devices at many
remote locations. By means of the commu-
nications equipment,
input is received by
the Computer and results are returned to
the inquirer.
The following
paragraphs discuss the Real-
Time Computer
and its peripheral units.
Peripheral Units
The Real-Time Computer can accommodate
a
large variety of peripheral units. For
example, it can handle UNIV AC Solid-
State Subsystems equipment such as the
High-Speed Printer, the High-Speed Card
Reader, and the Punch-Verifier Unit. Uni-
servo
IIA and Uniservo III tape handlers
can be connected to the system. In addition,
mass-storage devices
of the random access
type such as flying-head drums, can also be
incorporated into a Real-Time System.
Peripheral Systems
The central site peripheral systems are
listed as follows:
Flying-Head Drum Subsystem
A Channel Synchronizer
A
Drum Control Unit
One to eight Drum Units

UNISET
UNISET
PROGRAMMER
COMMON CARRIER-
SUPPLIED
SUB-SETS
COMMUNICATIONS
CONTROL UNIT
-
COMMUNICATIONS
CONTROL UNIT
SCANNER
BUFFER
UNISET
PROGRAMMER
UNISET
SCANNER
UNISET
UNISET
t
COMPUTER
CONSOLE
UNIVAC 490
REAL-TIME
COMPUTER
SCANNER-SELECTOR
COMMUNICATIONS
CONTROL UNIT
TELEGRAPHIC
HALF-DUPLEX CENTRAL
CHANNEL
SYNCH.
MAGNETIC
CHANNEL
SYNCH.
~ DRUM ~
CONTROL UNIT
URTS INTERFACE
(CENTRAL SITE)
--
I -
CCU PARTY
rt-
MODEM
LINE MASTFR
I
---
-l-t~ - - URTS
INTERFACE I
DATA SUB-SET
COMMON CARRIER
SUPPLIED
- -1-1 I-CO~N ;;RI;- - -
I I LINES - - I
I
Figure 3-1. Typical Central' Site Layout
HIGH-SPEED
PRINTER
UNISERVO
IIA OR III
FH-880
PARTY LINE
SERVICE
TYPICAL
LAYOUT
-~
I
p:-
I--
ICOMMON
-CARRIER
LINES

14
Magnetic Tape Subsystem
A Channel Synchronizer
A Magnetic Tape Control Unit
One to Twelve Magnetic Tape-Handling
Units (Uniservo IIA)
High-Speed Printer Subsystem
A Channel Synchronizer
A High-Speed Printer Control Unit
One or two High-Speed Printers
Card Equipment Subsystem
A Channel Synchronizer
A Card Equipment Control Unit
A High-Speed Reader
A Punch-Verifier Unit.
To communicate with the computer each
peripheral subsystem utilizes an input-out-
put channel. Anyone of the peripheral
systems may be connected to anyone of the
12 input-output computer channels. Thus
as many as 12 peripheral sUbsystems in
various combinations may be connected to
the 12 Computer input-output channels.
Magnetic Drum Storage
In addition to major features such as large
capacity and high-speed random access
these mass-storage units employ the flying
head (air-floating head) technique which
combines aerodynamic and pneumatic prin-
ciples. The read-write heads float at one-
half a thousandth of an inch or less from
the oxide-coated surface of the drum, on a
boundary layer of air, generated by the
rotation of the drum. The read-write heads
are suspended in position by the opposing
forces
of the boundary layer of air and the
head-positioning mechanism.
Flying-Head Drum Storage FH-880
In the FH-880 Drum Storage Unit forty
head blocks are positioned around the
drum. Mounted in each are 22 read-write
heads, one for each recording track which
revolves
beneath the block. The read-write
heads record information on the drum sur-
face at a density of 490 bits per inch while
it revolves at 1800 rev0lutions per minute.
Recording
frequency is approximately 1
megacycle.
There are 128 6-track bands across the
drum. Each band can store 6,144 computer
words, allowing a total of 786,432 words to
be recorded on the drum. Average access
time to information stored on the FH 880
drum is one-half drum revolution or 17
milliseconds.
Read-Write Operations
The 30-bit computer words are divided into
five 6-bit groups as they are recorded on the
surface of the drum. Each 6-bit group is
written in parallel followed by the next
group and so on until the word is written.
Each word is considered one angular ad-
dress and hasa parity bit associated with it.
When performing a read or write operation
on the flying-head drum storage, the
computer:
1. Sets up a buffer mode
2. Sends a function word to the storage control unit
via the channel synchronizer.
The function word contains the starting
address and a code specifying which opera-
tion is to be performed. The end of the Com-
puter buffer mode will stop the operation.

When a read is to be performed, the storage
system locates the starting address and
reads the word at that location, and then
the input request signal is sent. If an "ac-
knowledge" is received before
the begin-
ning of the next word, the information can
be read into the Computer as fast as it
comes off the drum. This rate can be varied
by integral powers of 2, starting from 16.4
microseconds up to a
maximum of 262 mi-
croseconds. Consecutive words
are read in-
to
the Computer until the buffermode ends.
The write operation is similar to the read
operation except that the output request
signal is transmitted to the Computer im-
mediately upon receipt
of the function
word.
Then the storage system looks for
the address and receives a word from the
Computer at the same time.
Drum Search
Two types of drum search are available,
each using a one-word identifier. One
type
will locate the matching word and store its
address. The other initiates a read opera-
tion
starting with the word following the
matching word.
Overflow words can be
inserted at any loca-
tion preceded by an end of block which is
represented by thirty 1-bits. These words
will contain
an address and an identifying
code. When an overflow word is reached
during a search, the search will stop at that
point and the overflow address is sent to
the computer. The search can be reinitiated
under program control at the location speci-
fied by
the overflow address. The End of
Block word can also stop a search before a
find
has been made.
Magnetic Tape Storage
As many as 12 UNISERVO IIA magnetic
tape units may operate with a UNIVAC
Real-Time Computer through a tape con-
trol unit and a channel sychronizer.
Themultiple control
units and large storage
facilities of the Computerprovide for simul·
taneous tape reading, tape writing, and
computation. This means that a 2400-foot
reel of tape, containing a data-history file,
may be read, updated, and rewritten on an
output tape in the time required to read the
original file.
The tape units provide fast tape-mounting
and ease of operation. A switch on the front
panel of each unit permits interchanging of
metallic or Mylar* tape. A number of
checks is incorporated into the unit to pro-
vide
and maintain accuracy of information
as it is read or recorded.
*Mylar is a registered trademark of E. 1. du Pont de Nemours
and Company, Inc.
15