UNIVAC 1218 CPU (Univac 1500)

In 1981, I attended computer school in the Marine Corps at the Naval Air Station in Meridian, Mississippi. The first time I had ever seen a computer, and what a beauty she was! The UNIVAC (UNIVersal Automatic Computer) 1218 Military Computer…

Univac 1218 CPU
Univac 1218 CPU
Along with the IBM card reader punch interpreter (CRPI), four mag tape drives (model 1240), Hetra 3300 high speed printer (600 LPM), and a very large 7-track magnetic tape library, one could indeed consider themselves in a pioneer environment. With the UNIVAC system still serving from the 60’s, it was old compared to the larger Honeywell and DEC systems the Navy was converting to at the time. She had 4k (expandable to 16k) of memory and cost just about $100,000 and weighed nearly 800 lbs.

Complete with other peripherals, the system would cost just under $400,000. When new (was it 1964?) it was advertised like this “With a core memory cycle time of 4 microseconds and powerful Input/Output features it is capable of processing large quantities of real time data”. woah! Tell me it isn’t so! But this was 1981! As you may know, the Marines always make the best of hand-me-down technology while the Navy and Air Force get the big capital budgets for the latest and greatest toys.

In our environment, these computers kept track of inventory parts for combat aircraft (namely A-4 skyhaws, A-6 Intruders, and CH-46 helicopters), among other things. Keeping records for the entire Aviation Group Supply Squadron, these systems were critical tools in keeping these airplanes flying.

Beddoe in the ADP vans, MCAS Iwakuni, 1982
Beddoe in the ADP vans, MCAS Iwakuni, 1982
These photos were taken in the ADP computer vans at H&MS-12 Marine Corps Air Station Iwakuni Japan, 1982. Computer operators had a military occupational specialy code of 3073 (MOS:3073) and the technician was MOS:5982. If I recall, the programmers were MOS:4044, but I could be wrong. I don’t believe the MTBF in excess of 1,000 hours ever held true. Seems the techs were always working on that CRPI.

I can almost recall the reboot sequence required to restart the system. Pressing the right toggle switches in the right sequence would start a hundred LED lights flashing for a few seconds before you would hear the ole’ teletype start to print out some power-on-self-test code on the large roll of yellow paper. There were no monitors back then. There also were no hard disk drives. You had input (IBM mechanized punch cards & mag tape), processing (sorting on mag tape), and output (mag tape or 6-part carbon paper). We’d print out boxes upon boxes of paper and spend hours decollating or separating the six copies of paper from the 5 films of carbon in between.

We had a key punch group who would spend hours punching little holes in 80-column cards, based on paper received from programmers.

Sgt. Barnes in the keypunch area
Sgt. Barnes in the keypunch area

On occasion, a tray of punched cards, ready to be read in to the card reader, would spill. You DID NOT want to tell the key punch operator that he had to re-do his work because you spilled his cards. It happened, and it was not fun. That’s Sgt. Barnes in the John Cougar t-shirt, standing in the keypunch area.

As old as these systems were, you could still play ONE game on it, called Adventure. Written in 700 lines of Fortran, Adventure was the FIRST computer adventure game. “You are in a maze of twisty little passages, all alike”, and beware the axe-throwing elf! XYZZY –> Nothing Happens

So what was it like operating a large 1960’s Univac computer? It was a challenge.

Miller and Rod
Miller and Rod
Some jobs would take days to run and during each shift turnover, you would explain to the next shift coming in where you were with the job, hand him the bottle of alcohol and q-tips, and wish him good luck. (I know those of you that know what I’m talking about are having a good laugh at that one). Then you’d run off to mid-rats (chow hall) to get some eggs and potatoes before they closed (Marine Corps = Every Day a Holiday & Every Meal a Feast). If everything went well, an eight-hour shift could exist of updating the tape library, managing a box or two of printouts, and writing both of those tasks in the log book. Under normal circumstances, we’d wear noise-canceling ear protectors, since those systems were pretty loud. And because of the A/C requirements, we’d usually wear heavy field jackets, especially in the winter. If there were problems, you’d have to call in the technicians, and then just stand back. Those techs were awesome! They really knew how to use an 0-scope and a soldering iron.

After a few years of the UNIVAC 1218, our shop migrated to the newer Honeywell DPS-6. We attended computer training for the Honeywell and we were very impressed with the possibilities of the new systems we were about to deploy.

Mag Tape Drives
Mag Tape Drives

These new systems had Winchester hard drives! Imagine the possibilities! We received real CRT monitors and felt like were had leading edge technology. Now, in 1984, these systems were not leading edge, but for us, it was like cave men discovering fire! We were excited indeed! 1,$!P

You gain a real appreciation for data processing when you grow up in a computer environment like this, with printed circuit boards, paper tape, 4k memory, and trial by error. You obtain real keen trouble-shooting skills as well.

I wouldn’t trade those experiences for anything. The friends I made in the Marine Corps, working on these Univac systems, are still my best friends!

As long as I have at least 4k of memory left, I will think of them all, every day. I am sure that when I leave this world, my last thought will be of my family and my comrades…..such good men.
~Cpl. Wally Beddoe

Univac 1218 Details from: BRL Report 1964


UNIVAC 1216 Military Computer


UNIVAC Division of Sperry Rand Corp. (Military)

Photo by the UNIVAC Division, Sperry Rand Corp.


General Purpose Computing
Multi-Computer in-line application
Range Instrumentation
Missile Guidance
Missile Fire Control
Message Switching
Ground Support Checkout
Tactical Control
Digital Communications
Data Reduction and Analysis
Inventory and Scheduling


Internal number system Binary
Binary digits/word 18
Binary digits/instruction 18
Instructions/word 1
Instructions decoded 98 including 18 I/0
Arithmetic system Fixed point

Parallel, ones complement, subtractive arithmetic
is performed.
Instruction type One address
Number range ± 131,071 (17 bits + sign) and
± 34, 359 738, 367 (35 bits + sign)

BRL 1964, UNIVAC 1218, starting page 0292

Instruction word format
FORMAT I | 17 12 | 11 0 |
| f | u |
FORMAT II | 17 12 | 11 6 | 5 0 |
| f | m | k |

f – function code
u – operand address
m – minor function code
k – designator used for channel number, shift count,

Automatic built-in subroutines

32 words of non-destructive read-out (NDRO) memory are furnished to
provide initial load and error recovery routines.

Automatic coding.

No computer independent compiler is provided, however the TRIM III
Assembly System provides for automatic generation of certain program

Registers and B-Boxes

The following are the addressable registers:
1 AU – Register (Upper Accumulator, 18 bits)
1 AL – Register (Lower Accumulator, 18 bits)
1 ICR – Register (Index Control Register, 3 bits)
1 SR – Register (Special, 4 bits)
1 P – Register (Program address, 15 bits)

The UNIVAC 1218 is essentially programmed for 4,096-word modules
however each instruction that references memory is capable of
addressing any other cell in memory.

The UNIVAC 1218 has a complete repertoire of instructions that is
especially generous in the control of I/0.

Four instructions provide built-in double precision Add and Subtract.


Incl. Stor. Access Excl. Stor. Access
Microsec Microsec
Add 8 6
Malt 26 – 48.7 —
Div 48 —
Arithmetic mode Parallel
Timing Synchronous
Operation Sequential/Parallel


No. of No. of Access
Medium Words Digits Microsec
Magnetic Core 4,096 – 32,768 18 1.8 access
4.0 cycle
Magnetic Core (NDRO)* 32 18 4.0 cycle
FH 880 Drum 786,432 words/drum 36 17 ms
(8 per channel) (Average access)
Magnetic tape
No. of units that can be connected 16 Units/channel
No. of chars/linear inch 556 Chars/inch
Channels or tracks on the tape 7 Track/tape
Blank tape separating each record 0.75 Inches
Tape speed 112.5 Inches/sec
Transfer rate 62.5 Chars/sec
Average time for experienced
operator to change reel of tape 30 Seconds
Physical properties of tape
Width 0.5 Inches
Length of reel 2,400 Feet
Composition Mylar

The magnetic tape subsystem, Type 1240 is a fully compatible magnetic
tape format at 200 or 556 chars/ inch. It has search and other special

* Non-destructive read-out

Medium Speed
Card Reader 600 cards/min (Commercial, 80 or 90
Paper Tape 300 chars/sec (5 to 8 level)
Keyboard Manual (Provides alphanumeric
data entry)
Teletype 10 chars/sec
Paper Tape and Keyboard are included in Programmers
Console, Type 1232.


Medium Speed
High Speed Printer 600 lines/min(Commercial)
Card Punch 150 cards/min (Commercial 80 or
90 column)
Paper Tape Punch 110 chars/sec (5 to 8 level)
Monitor Printer 10 chars/sec

Paper Tape Punch and Monitor Printer are included in Programmers
Console, Type 1232.

Type Quantity
Magnetic Cores 73,728 to 589,824
Number of cores varies according to memory size, e.g., 73,728/4,096
words of memory.


Programmed parity checking.


Power, computer 0.85 Kw
Power, blowers 0.15 Kw
Volume, computer 23.3 cu ft
Area, computer 3.9 sq ft
Floor loading 198 lbs/sq ft
198 lbs concen max
Ambient air cooled; equipment included in computer
Weight, computer 775 lbs

May be ship or van mounted. Does not require false floor. Power
required is 115 V, 1 phase, 60 cycle and 115 V, 3 phase, 400 cycle.


Basic System/Component Purchase
Minimum 1218 Computer: 4k memory,
4 I/0 $ 96,000
Most common 1218 Computer:
16K memory, 8 I/0 127,000
Militarized Mag Tape System
(2 handlers) 80,500
Paper Tape Subsystem incl.
keyboard & printer 25,000
High speed printer system 77,500
80 column card system 83,250

Fixed price sale only on 1218 basic system.

BRL 1964, UNIVAC 1218, starting page 0293

Monthly Lease
Control & Synchronizer 1,530
Power Supply 550
High Speed Printer 500
Control & Synchronizer 1,450
Card Reader 350
Card Punch 500

Control & Synchronizer
for Reader & Punch 1,600
FH 880 Drum 2,000
Control and Synchronizer 1,420

One 8-Hour Two 8-Hour Three 8-Hour
Shift Shifts Shifts

Supervisors 1 1 1
Analysts 2 2 2
Programmers 4 6 8
Clerks 1 2 2
Operators 1 1 1
Technicians On call On call On call

Training made available by the manufacturer to the user includes
programming and maintenance courses, held upon request at St. Paul,
Minnesota and at the customer’s site. Complete training and
maintenance courses are available and UNIVAC Military Field
Engineering service is available on a world-wide basis.


It is expected average meantime between failures
(MTBF) will be in excess of 1,000 hours. The UNIVAC
1218 was designed using MIL-E-16400D as a guide plus
MIL-I-16910A, MIL-STD-108D, MIL-S-901, and MIL-STD-167


Outstanding features include 8 I/0 channels, buffered input/output;
any or all channels may by intercomputer; real-time interrupt s;
powerful instruction repertoire.

Unique system advantages include small physical size, resistant to
shock, vibration, unusual climate conditions and radio frequency
interference (RFI). Compatible with the Naval Tactical Data System
(NTDS) peripheral equipment and can be direct cable-coupled to large
scale UNIVAC computers.

Designed to meet MIL-E-16400D
Repertoire of 98 instructions
Real time millisecond clock capability
Average instruction time 8-12 microseconds
Memory cycle time 4 microseconds

Up to 8 Input and 8 Output channels; each may be intercomputer;
channels may be paired to form 36-bit interface.

All Input/Output transfers fully buffered

33 distinct automatic interrupts standard with 8 I/0 channels

32 words of permanent memory.

The new UNIVAC 1218 Military Computer is a versatile stored program,
medium scale, general purpose digital computer designed to provide
high reliability under advance operational environments.

With a core memory cycle time of 4 microseconds and powerful
Input/Output features it is capable of processing large quantities
of real time data.

Semper Share: