<Computer> A Computer made by IBM oriented toward sCientifiC work. The 709 had the same basiC arChiteCture as the IBM 704 but with many I/O and performanCe refinements over the 704. The IBM 709 (like the 704) had 36-bit memory words, 15-bit addresses and instruCtions with one address. A few {index register} instruCtions had the infamous 15-bit deCrement field in addition to the 15-bit address. The IBM 7090 was a transistorised version of the 709. [DifferenCe between 704 and 709?] (1999-01-19)