pdp-6

from The Free On-line Dictionary of Computing (8 July 2008)

PDP-6

   <computer> Programmed Data Processor model 6.  A computer
   designed around 1960 with more or less exactly the same
   hardware architecture as the {PDP-10}.  It already had
   multi-user {time sharing} and {batch processing} and
   multi-level priority {interrupts}

   (1996-12-21)