IBM 7070

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IBM 7070
IBM 7070 transistor circuit SMS boards

IBM 7070 was a decimal architecture intermediate data processing system that was introduced by IBM in 1958.[1] It was part of the IBM 700/7000 series, and was based on discrete transistors rather than the vacuum tubes of the 1950s. It was the company's first transistorized stored-program computer.[2]

The 7070 was expected to be a "common successor to at least the 650 and the 705".[3] The 7070 was not designed to be instruction set compatible with the 650, as the latter had a second, jump address in every instruction to allow optimal use of the drum, something unnecessary and wasteful in a computer with random access core memory. As a result a simulator was needed to run old programs. The 7070 was also marketed as an IBM 705 upgrade, but failed miserably due to its incompatibilities, including an inability to fully represent the 705 character set; forcing IBM to quickly introduce the IBM 7080 as a "transistorized IBM 705" that was fully compatible.

The 7070 series stored data in a 10 decimal digit plus sign word. Digits were encoded using a two-out-of-five code. Characters were represented by a two-digit code. The machine shipped with 5,000 to 9,990 words of core and the CPU speed was about 27KIPS. A typical system was leased for $17,400 per month or could be purchased for $813,000.

Later systems in this series were the faster IBM 7074 introduced in July 1960[4] and the IBM 7072. They were eventually replaced by the System/360, announced in 1964.

See also[edit]


  1. ^ Trucks, sheep and the IBM 7070, IBM
  2. ^ Emerson W. Pugh, Lyle R. Johnson, John H. Palmer, IBM's 360 and early 370 systems, MIT Press, 1991, ISBN 0-262-16123-0, p. 50
  3. ^ Bashe, Charles J.; Johnson, Lyle R; Palmer, John H.; Pugh, Emerson W. (1986). IBM's Early Computers. MIT. p. 473. ISBN 0-262-02225-7. 
  4. ^ "A Quicker Computer Introduced by I.B.M.". New York Times. July 8, 1960. IBM offers speedier 7074 computer to rent for $29,300 a month. 

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