|Manufacturer:||International Business Machines|
|Year Announced:||April, 1952|
|Year Design Started:||February, 1951|
|Year First Shipped:||December, 1952|
|Year Discontinued:||June, 1954|
|Word Size:||18 or 36 bits|
|Logic Type:||vacuum tubes|
|Clock Speed:|| 60 μsec (basic add instruction)|
456 μsec (multiply instruction)
|Price:||US$15,000/month (rental only)|
The IBM 701 (initially known as the IBM Defense Calculator) was IBM's first commercial computer; it was later described as being "key to IBM's transition from punched-card machines to electronic computers". It was a vacuum tube scientific mainframe (built at a time when computers were generally only used for scientific, and not business, computing).
It was announced in April, 1952. 19 were produced (18 by June, 1954, when production ended; the last was a later special order for use in weather forecasting by the US government).
It was a fairly modern machine in architectual terms, compared to its close contemporary, the IBM 650; it was parallel, not serial, and it used binary internally. It used Williams tube electrostatic cathode ray tubes for main memory; each tube held 1K bits, and a bank contained 36 tubes. Configurations could have either one or two banks.
Secondary storage included up to 4 drums, each holding 2048 long-words, capable of transferring 800 words/second. A system included four magnetic tape drives, using 1/2" plastic tape; the first magnetic tape on a computer.
- Charles J. Bashe, Lyle R. Johnson, John H. Palmer, Emerson W. Pugh, IBM's Early Computers, MIT Press, Cambridge, 1986
- IBM 701 - IBM Archive page