RFC 549 (rfc549) - Page 2 of 12

Minutes of Network Graphics Group meeting, 15-17 July 1973

RFC 549               Minutes of Network Graphics        15-17 July 1973


      and aircraft position and velocity.  These descriptions are highly
      encoded--they are not pictures in any general sense.  The rate at
      which the simulation proceeded was adequate.

      Jim Michener described the results of an experiment in which the
      E&S LDS-1 at MIT-DMCG was used to generate stylus inking input for
      a character recognition program at SDC.  The experiment was
      plagued with difficulties including bugs in SDC's NCP and
      scheduling of experimental/debugging sessions.  When the
      experiment was finally terminated (due to planned extensive
      hardware modifications at DMCG) a clear understanding had not yet
      emerged, but apparently network transmission delays had been
      experienced of up to 20 seconds.

      Dan Cohen described an Aircraft Flight Simulator which interacts
      with a user at the Harvard PDP-1.  The simulation takes place on a
      PDP-10.  Network traffic is approximately 200 bits from the PDP-1
      to the PDP-10 and several thousand bits in the opposite direction.
      It has been found that at least 5 updates are required per second
      to give the "pilot" an adequate feeling of control.  The Harvard
      PDP-10 and one at BBN have been used, the latter at 6 AM to avoid
      loading problems.

      John Pickens described UCSB's status regarding output in level 0
      Network Graphics Protocol (NGP-0).

      Steve Bunch reported that he has an Imlac monitor which accepts
      NGP-0 directly.  Programs have been developed at CCN (using
      subroutine packages modeled after plotter packages) which build
      files containing pictures in NGP-0.  Other programs output the
      pictures either to a Gould plotter or a storage display (in device
      specific code) or to an Imlac (in NGP-0 form).

      Steve Holmgren briefly described a Fancy Arpa Network Graphics
      System (FANGS) under development at UCSD.

   Discussion of Modifications in the Graphics Protocol

      David Egli reported that he and Jim Foley (of Univ. of North
      Carolina) thought that the graphics protocol should have the
      ability to replace items, and that 3 dimensional data should be
      allowable.  Jim Foley also thinks that a subpicture call should be
      able to specify a rate of rotation, scaling, and translation, in
      addition to initial values for these.

      An extended coffee break followed to allow perusal of the
      documents distributed.