Trek73 is a computer game based on the original Star Trek television series. It was created in 1973 by William K. Char, Perry Lee, and Dan Gee. The game was played via teletype. Roderick Perkins adapted the program for the LHS DECISION computer located at the Lawrence Hall of Science in Berkeley, California. Dave Pare and Chris Williams translated the BASIC into C and Jeff Okamoto, Peter Yee, and others corrected and enhanced the code.
The game simulates battles between space ships of the Star Trek franchise. Through text commands, a player may order the ship to perform certain tasks in battle against an opposing vessel.
In January 1973, William K. Char began programming a space battle game in BASIC on a time-shared Hewlett-Packard 2000C system at Wilson High School in San Francisco. The first version of what was then called $SPACE was introduced in May 1973. In June 1973, Char, Perry, Lee, and Gee started programming TREK73; it was completed October 8, 1973. Roderick Perkins adapted TREK73 for the DECISION computer at the Lawrence Hall of Science in 1974. The game was played by Homebrew Computer Club member Steve Dompier, who purchased a teletype for his home so that he could play the game for hours without interruption.
Dave Pare and Chris Williams at the University of California, Berkeley independently translated TREK73 into the C programming language in 1984. In April 1985, Jeff Okamoto and Peter Yee combined the Pare and Williams versions into one. The command set was expanded to 31. This version had enhancements based on the boardgame Star Fleet Battles. The player was also capable of designing his own ship. David Soussan then ported the Okamoto/Yee version to MS-DOS, having played it in high school.
While at the University of Iowa, Tom Nelson and Mike Higgins played and made modifications to TREK73 on one of the University HP2000 system. In 1984 they created Begin - A Tactical Starship Simulation for MS-DOS. Begin was not a port of TREK73. It was written in C and was very much inspired by TREK73. In 1993 Higgins released Begin 2, a VGA version for MS-DOS, and in 2009 Nelson released Begin 3 for Windows.
In 1985 while at the University of Michigan, Howard Chu wrote a version of TREK73 in Turbo Pascal for MS-DOS. This may have been the first version to use a screen-oriented interface and function-key command input. 
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- TREK73 Page