AND TIME AVAILABILITY
Average error-free running period Approx. 6 hours
~provement, and the incorporation of new components.
ADDITIONAL FEATURES AND REMARKS
The ORDVAC belongs to the group o~ computers whose basic logic'was developed by the Institute ~or
Advanced Study and utilized in the IAS computer.
This IAS ~amily o~ computers is made up o~ such machines as the ILLIAC, ORACLE, AVITJAC, MANIAC, JOHNNIAC, MISTIC, and CYCLONE.
The ORDVAC is a direct-coupled machine using three-dimensional construction. A direct-coupled machine is one that connects the voltage level o~ one com··
ponent directly to the input o~ the next, without voltage isolation between. This ~eature is very helpful in trouble-shooting the system. Three-dimensional construction is sometimes called low-capaci tance wiring. In the ORDV AC, three-dimensional wiring is employed by placing the arithmetic unit and other controls on opposite sides, and inter-connected wiring running across the open space between. The machine can be remotely controlled
~rom commercial Teletype units.
ORDVAC is equipped with the option o~ two di~~erent
instruction codes. Code -9 (nine bits per instruc-tion) makes 1,024 words o~ high speed core storage available to the operator while Code -6 (six bits per instruction) makes 4,096 words o~ high speed storage available. Each code shares a common nine-bit decoder; however, when the code -6 option is used the instruction ~irst passes through a code translator which translates the six bit instruction into its 9-bit equivalent. There is no loss o~ time while making the code translation.
The translator uses the ~ollowing number o~
circuit elements Transistors
SB 100 2N 43 2N 140 Total Crystal diodes Resistors Capacitors
135 24 12 171
The above components FI.rl" 'nounted on 21 printed circuit boards. Power dissipation is approximately 5 watts.
INSTALLATIONS
Ballistic Research Laboratories Aberdeen Proving Ground, Maryland
FUTURE PLANS
The Floating Point unit ~or the ORDVAC Willl~7 fUll~1~8ansistorized, with a number range o~ 2 to 2 , using a seven bit biased exponent. Num-bers will be normalized automatically on trans~er to storage. The mantissa o~ the normalized ~loat
ing-point number will have a range o~ 1/2> C
>
-1/2.~is system will require that an existing register be converted ~rom a one-sided shi~ting register to a two-sided shifting register.
Fully transistorized control circuitry for new indexing orders will be added in the near future.
739
General purpose magnetic tape stations will be added to the ORDVAC shortly, with provisions for 8 stations. ORDVAC will control read, write, re-wind
~orward and backward, move tape ~orward and back N words, starting at A address of memory, transfer to B address o~ memory for next instruction, re-record N words, pl~back N words, check ~or parity error,
trans~er on error, and other ~unctions.
Circuit Elements, Entire System Magnetic Cores
Quan OD
172,032 100 5,376 375
ITJ 70 260
Thick 30 125
mils mils
ORDVAC
PACKAR 0 BELL 250 MANUFACTU RER
Packard Bell Computer ~el 250
APPLICATIONS
The PB 250 is a high speed digital computer designed to be used for general purpose computing and as a system component for on-line, real-time, data hand-ling.
PACKARD BELL 250
740
Packard Bell Computer Corporation
Photo by Packard Bell Computer Corporation
PROGRAMMING AND NUMERICAL SYSTEM
Internal number system Binary Binary digits/word 21 plus Sign Binary digitS/instruction 22
Instructions per word I Instructions decoded 63
Arithmetic system Fixed point Floating point by subroutine
Instruction type One address (Mod1f'led) Number range 6 dec:1mal. digits
INPUT
CORE OUTPUT
HIGH- SPEED BLOCK MEMORY
HIGH- SPEED BLOCK
TRANSFER (EXTERNAL) r TRANSFER
~
MAIN MEMORY
CARD READER ... CARD PUNCH
TYPEWRITER
l
TYPEWRITERLOW-SPEED PAPER TAPE
TAPE RE~DER CHARACTER CHARACTER PUNCH
H
INPUT BUFFERHIGH-SPEED
r--. r--.
bUTPUT BUFFERr-t
MAGNETICTAPE READER ARITHMETIC
TAPE UNITS
Instruction word format
22 15 14 13 8 7 3 2 1 modifica-tion while maintaining optimum programming.
Optimum programming is provided for by provision for relative addressing for next instruction.
Automatic built-in subroutines include square root and gray-to-binary conversion.
ARITHMETIC UNIT
Arithmetic mode Serial
Timing Synchronous
Microsec 12 276 (max) 252 (max) Operation Sequential or non-sequential
The PB 250 operates at a clock frequency of 2 Me giving a word time of 12 microsec. The arithmetic unit is completely serial in operation as is the magnetostrictive delay line memory. The serial
approach provides low component count with low cost and high reliability. The 2 Mc clock provides micro-second speed formerly associated only with very large expensive machines. The magnetostrictive delay line memory can be expanded from the basic 1808 words in
Block Diagram by Packard Bell Computer Corporation
STORAGE
Physical properties of tape Width
OPERATIONS GROUPING or combined for multiplication, division, square root, and double precision operations.
C Register: For multiplication, division, tally, and control.
Mnemonic Numeric
Operation Code Code Description
ADD 14 Add
SUB 15 Subtract
DPA 16 Double Precision Add DPS 17 Double Precision Subtract
SQR 30 Square Root
VLS 30 Variable Length Square Root
Arithmetic DIV 31 Divide
VLD 31 Variable Length Divide MUP 32
~~~i~g:~
Length MultiplyTRU 37 Transfer Uncon itionally TOF 75 Transfer on Overflow
STD 13 Store Double Preci9ion MCL 71 Move Command Line Block
DIU 50 Disconnect Input Unit RTK 51 Read Typewriter Keyboard RPT 52 Read Paper Tape RFU 53 Read Fast Unit
Input· LAI 55 Load A From Input Buffer
Output CIB 57 Clear Input Buffer
WOC 6X Write Output Character
Media
70 Pulse to Specified Unit 72 Block Serial Output 73 Block Serial Input
OUTPUT
character buffer 'Which is used for Flexowriter, Paper Tape, and Magnetic Tape input and output. ForCode Code Description
00 HLT Halt
13 STD Store Double Precision
14 ADD Add
15 SUB Subtract
16 DPA Double Precision Add 17 DPS Double Precision Subtract 20 NAD Normalize and Decrement 37 TRU Transfer Unconditionally 40 EBP Extend Bit Pattern
50 DIU Disconnect Input Unit 51 RTK Read Typewriter Keyboard
52 RPT Read Paper Tape
53 RFU Read Fast Unit
55 LAI Load A from Input Buffer
56 CAM Compare A and M
57 CIB Clear Input Buffer 6X WOC Write Output Character 70 PTU Pulse to Specified Unit
Command. List by Packard :Bell Compu.terCorporation available. 32 control output lines are available for use 'With the Pulse to Specified Unit command for control applications.
Both punched card and line printing equipnent v1ll be available by mid 1961.