IBM 360

computer The generic name for the CPUs and architecture

released by IBM in 1964. The 360 was marketed as a general

purpose computer with 'all round' functionality - hence 360

(degrees).

Models ranged from the 360/20 to the 360/65 and later the

360/95, with typical memory configurations from 16K to 1024K.

Elements of the architecture, such as the basic instructionset are still in use on IBM mainframes today. Associated

operating systems included DOS, OS/MFT and OS/MVT.

The 360 architecture was based on an 8-bit byte, 16 general

purpose registers, 24-bit addressing, and a PSW (Program

Status Word) including a location counter.

Gene Amdahl, then an IBM employee, is generally acknowledged

as the 360's chief architect. He later went on to found

Amdahl Corporaton, a manufacture of PCM mainframe

equipment.

The 360's predecessors were the smaller IBM 1401 and the

large IBM 7090 series.

See also ABEND, ALC, BAL, Big Red Switch, HCF, modebit, PL360, PL/S.

(1999-01-24)