A computer made by IBMORiented 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)