IBM 709
| IBM 709 | |
| Manufacturer: | International Business Machines |
|---|---|
| Year Announced: | January, 1957 |
| Year Discontinued: | April, 1960 |
| Form Factor: | mainframe |
| Word Size: | 36 bits |
| Logic Type: | vacuum tubes |
| Instruction Speed: | 24 μsec (basic add) |
| Memory Speed: | 12 μsec |
| Operating System: | SOS, IBSYS, IBJOB |
| Predecessor(s): | IBM 704 |
| Successor(s): | IBM 7090 |
| Price: | US$2.6M (and up) |
The IBM 709 was IBM's last major vacuum tube scientific mainframe (built at a time when computers for scientific and business computing used separate instruction sets). It was announced in January, 1957
Major advances over its predecessor, the IBM 704, included indirect addressing, and channels (called 'Data Synchronizers' at the time). A Data Synchronizer had two channels, to each of which could be attached a card reader, card punch and printer; up to eight magnetic tape drives could be attached to a single channel.
One peculiarity of the index registers was that there were three, selected by a 3-bit field in the instruction, each register being selected by one bit; if more than one bit was set, the registers indicated were logically ORed together before being used!
One major advance pioneered on the 709 was time-sharing; the first time-sharing operating system, CTSS, was first experimentally operated on a 709.
Its lifetime was shortened by the switch to transistors as the technology for computers.
Further reading
- Charles J. Bashe, Lyle R. Johnson, John H. Palmer, Emerson W. Pugh, IBM's Early Computers, MIT Press, Cambridge, 1986
