[W/K] :: IBM 360

  IBM 360
       
           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 instruction
          set 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, mode
          bit, PL360, PL/S.
       
          (1999-01-24)