TheUNIVAC 490 was aUNIVAC computer with 16K or 32K words ofmagnetic-core memory. The words had 30 bits and the cycle time was 4.8microseconds. It was a commercial derivative of theinstruction set that had been developed for theAN/USQ-17 bySeymour Cray for theUnited States Navy. This was the last machine that Cray designed before leaving UNIVAC to join the earlyControl Data Corporation.
Univac Federal Systems would further develop this system into theAN/USQ-20 for the US Navy. That system was the heart of theNaval Tactical Data System which pioneered the use of shipboard computers forair defense. The military version went by a variety of names:UNIVAC 1232,[1]AN/USQ-20,MIL-1206 andCP642.
At least 47 of these machines were made (serial numbers run from 101 to 147). Six were installed atNASA and played important roles inGemini and theApollo missions. The U490 had complete control of most or all of the data readout screens inHouston Mission Control. TheUSAF had two installed, as didLockheed.[2]
Airlines using the 490 Real-Time system includedEastern andNorthwest Orient – principallyairline reservations systems atEastern Air Lines (1963) andBritish European Airways (BEACON – 1964).[3][4][5] Other commercial installations of the 490 Real-Time included two atWestinghouse, two at Hammermill Paper Company, and one each atAlcoa,U.S. Steel,Bethlehem Steel andGeneral Motors.[2]
The only surviving, nearly complete, original, civilian version of the 490 Real Time System is on display at theSystem Source Computer Museum inHunt Valley, Maryland. It has six banks of memory cores. System Source also has a nearly complete set of original documentation for the machine, including original blueprints and troubleshooting data. This includes the Boss and Wilen troubleshooting document.[2]
The standardoperating system was REX (RealTime Exec), except at Eastern and B.E.A. where a custom operating system was developed for airline reservations (CONTORTS – CONTrol Of Real Time System). CONTORTS was the origin of Univac's subsequent RT operating systems for 494 (STARS) and later converted to the1100 Series (RTOS).
| Computer architecture bit widths |
|---|
| Bit |
| Application |
| Binary floating-pointprecision |
| Decimal floating-pointprecision |
The instruction word format:
Numbers were represented inones' complement.
The machine provided the programmer with the followingregisters:
The arithmetic unit used 13,819 transistors of various types and 37,543 diodes of various types.[6]
In June 1965, UNIVAC launched a family of successor systems known as the UNIVAC 490 Modular Real Time Systems. This consisted of the UNIVAC 491, 492 and 494.[7] The 494 was heavily used by NASA as part of the communications complex for the Apollo Mission.[8] Other users include BEA,Iberia Airlines,[9][10]Scandinavian Airlines[11] andLufthansa.[12]
Subsequently as UNIVAC decided to focus on theUNIVAC 1100/2200 series an option to run the 1110/80 in 494 mode was added. This emulator was implemented using microcode.