How Decwar Came About and Prospered as Megawars

"You know, we expected Compuserve customers to spend $10 to $15 a month. We never expected people to come online and spend $1200, $2000 a month playing Megawars." Bill Louden [1]

The story of how Decwar came about naturally begins with 1962 and Spacewar, a graphical videogame-style simulation of a battle between two spaceships, made feasible by the PDP-1 and absolutely requiring a graphical display. At the same time, in the fifties and sixties another style of simulation gaming was moving out of think-tanks like RAND and into the hobbyist world. These were generally tabletop games, but significantly they were often also heavily textual, so much so that they could be played via hand written letters and the mail. For mainframe computers without a graphical display, the textual Star Trek games of the early seventies fused the influences of both Spacewar and tabletop simulation gaming. And notably, at first these were definitely mainframe games, created and played at institutions like universities and large companies capable of supporting both expensive hardware and users with serious computer skills. At UT, the first Star Trek games were written on the very expensive 1966 CDC 6600 supercomputer. When UT purchased the more modern and interactive PDP-10 in 1975, Decwar and eighteen timesharing players became technically feasible and, curiously, its end-of-an-era mainframe genes made it much like having up to eighteen players gathered around a tabletop boardgame. If the players turned away from the game board (their terminals), nothing happened in the game. In fact, in the Decwar source code there are forty-six uses of the term board, for game board, compared to thirty-five uses of the term galaxy for the same spatial concepts. 

The Star Trek games and Decwar of course worked hard at creating the speed and excitement of Spacewar-style play, but it was somewhat of an illusion made possible by the speed of the computer, and at heart they were much like turn-based simulations not so different from those created at Avalon Hill or SPI. A slow version of Decwar could in theory be played on a tabletop with a grid game board, counters or game pieces, and dice, or by hand written letters and the mail for that matter. That the real game was so thrilling and addictive is a testament to the blending of both Spacewar’s energy and tabletop simulation gaming’s depth. The sight of Southwest Texas State University’s computation center terminal room in 1984, with Decwar players shoulder-to-shoulder, gazing intently into CRT terminals and poised to spring into action, couldn’t help but bring to mind the strategies and simulations captured in photos of the old SAGE Direction Centers and Combat Centers, which were in turn heavily influenced by the Software Development Corporation division of RAND. All of this was able to spread around the globe by simply mailing a letter and fifty dollars to UT and receiving a magnetic tape back, and that's exactly what Compuserve's Bill Louden did in early 1982.

Reconstruction of the UT Decwar 2.3 Source Distribution Tape is based on a snapshot of a Compuserve KI10 filesystem created around May 19, 1982. It includes the contents of the SDT sent by UT, with minimal modifications and diagnostics to integrate the game into Compuserve’s commercial environment and generate revenue. The calendar date comes from a memory map file that was likely generated as part of creating the snapshot. Compuserve had strong incentives to keep the initial changes minimal, as the extensive MACRO-10 assembly code is unforgiving to work with. Decwars, with an “s”, was first advertised in the Compuserve magazine in April 1982. By September 1982, it had become Megawars. The Compuserve KI10 was likely an older machine used for development and matching with the KI10 at UT, as Compuserve’s main customer-facing machine for multi-player gaming is believed to have been a newer dual KL10, and customers from across the country were routed to the KL within Compuserve’s internal network. [2][3]

SAGE Direction Center running software from the Software Development Corporation division of RAND.

Southwest Texas State University's computation center in San Marcos Texas, viewed from the north. The DEC-10 machine room was in the south-west corner, and the terminal room was in the core of the right-hand side of the building. The SWT and UT DEC-10s were in some sense siblings seperated by thirty miles of open countryside, at least back in the day.

The UT KI10 where Decwar was created, on the evening of The Soul of an Old Machine. [4]

[1] Interview with Compuserve's Bill Louden.

[2] Historical evidence of Compuserve's early work with the source code.

[3] April 1982 issue of Compuserve's Today magazine with a Decwar launch article. September 1982 issue with a Megawars launch article.

[4] The Soul of an Old Machine.