Source : Free On-Line Dictionary of Computing

parallel random access machine
     
         (PRAM) An idealised {parallel processor} consisting
        of P processors, unbounded {shared memory}, and a common
        {clock}.  Each processor is a random access machine (RAM)
        consisting of R {registers}, a {program counter}, and a
        read-only signature register.  Each RAM has an identical
        program, but the RAMs can branch to different parts of the
        program.  The RAMs execute the program synchronously one
        instruction in one clock cycle.
     
        See also {pm2}.
     
        (1997-06-04)