Source : Free On-Line Dictionary of Computing

TYMCOM-X
     
         {Tymshare}'s {operating system} which ran
        for many years on Tymshare's {PDP-10}s.  It was a descendent
        of {TOPS-10} but had many of the important features of
        {TOPS-20} such as real {paging} and controllable/spawnable
        processes.  TYMCOM-X, one of the best kept secrets in the
        PDP-10 folklore, was written by Bill Weiher, Vance Socci
        , Allen Ginzburg, Karen Kolling, Art
        Atkinson, Gary Morgenthaler (founder of the company that
        produced {IDRIS}), Todd Corenson and Murray Bowles.  Some
        copies still run today.  Most {TYMNET} development was done
        under TYMCOM-X and Tymshare sold a TYMCOM-X system to {TRW} to
        use in their credit reporting network, which was based on a
        purchased copy of TYMNET circa 1979.
     
        [E-mail from Vance Socci 1994-05-20].
     
        (1995-11-09)