IBM 7090

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IBM 7090
Manufacturer: International Business Machines
Year Announced: December, 1958
Year First Shipped: November, 1959
Year Discontinued: July, 1969
Form Factor: mainframe
Word Size: 36 bits
Logic Type: SMS cards using alloy-junction transistors
Clock Speed: 4.4 µsec (basic add instruction)
Memory Speed: 2.2 µsec
Physical Address Size: 15 bits (32K words)
Operating System: SOS, IBSYS, IBJOB, FMS, CTSS
Predecessor(s): IBM 709
Successor(s): IBM 7094
Price: US$2.9M (and up)


The IBM 7090 was IBM's first commercial transistor scientific mainframe (built at a time when computers for scientific and business computing used separate instruction sets).

It was upwardly compatible with its vacuum tube technology predecessor, the IBM 709. It had a performance of six times that of a 709, but only cost one third more.

It was designed hurriedly to meet the requirements of Sylvania, the data processing subcontractor for the BMEWS missile warning radar network, which was under a mandate to use transistor computers.

For this reason, it relied heavily on engineering from the STRETCH project; units such as power supplies, back panels and the memory unit were transplanted from STRETCH.

In addition to its use for the ground-breaking CTSS operating system, a pair of 7090's were used in the equally influential American Airlines SABRE real-time airline reservation system.

Further reading

  • Charles J. Bashe, Lyle R. Johnson, John H. Palmer, Emerson W. Pugh, IBM's Early Computers, MIT Press, Cambridge, 1986

External links