Retrochallenge 2010
      Winter Warmup
      Mark Wickens
      2-Jan-2010

                                          VAX Games

      It's been a slightly slow start this year, to say the least! A combination of
      the harsh winter weather here in Windermere, UK (our road has been a veritable
      ice rink for the last two weeks now) and seasonal colds all round have left
      little time for retro immersion. The plan was to jump out of the VAX camp this
      year and give the Motorola Education Computer Board (MECB) [1] which is a 68000
      based single board computer a trip into the limelight, but as an initial detour
      I thought it would be worth attempting to get a couple of VAX games that had
      dropped into my lap in the last couple of weeks working.

      This chapter started with a browsing session that lead me to the VAXMUF website
      [2]. VAXMUF is a 'multi-user roguelike role-playing game for VAX/VMS developed
      back in 1989 by two denizens of Strathclyde University as anm alternative to the
      existing VAXMUD'.

      The website provides an excellent insight into the game and its development and
      contains a simulation of the original game to give an idea of the look and feel.
      I took the time to contact the author who informed me that the source code for
      the game was in a bit of a sorry state having been corrupted due to the way in
      which it was transferred off the VAX. He did however have source code for two
      alternative games, DODGEMS and VAXMULC which he provided me to see if I could
      get them working. Personally he'd not touched a VAX for the best part of 20
      years.

      DODGEMS

      Stephen described dodgems using the line 'If you've ever played Grid-Run on a
      spectrum, you'll know this game'. The game was written on a VAX running VAX/VMS
      and designed to run on a VT terminal connected to the VAX using a 9600 baud
      line.

      The source code consists of two Fortran files. The result of getting the code
      compiled up was a couple of screen shots including the title screen and the main
      game screen, of which the second contains a problem to be addressed. The problem
      manifests itself on both a 'soft terminal' such as OpenVMS DECterm and a real
      VT320 terminal.

      Dodgems Title Screen
      
      Dodgems Main Screen

      So the first task is to find out why the game display is being corrupted. It's
      generated using hand-coded lines which include VT escape codes to generate the
      reverse video walls making up the race track.

      
      ENDNOTES

      1. Motorola 68000 Education Computer Board

      2. VAXMUF Multiuser Game