Xerox Sigma Computers at the San Antonio, Texas Gas & Electric Service

During the height of the 1960s go-go era, when conglomerate companies were believed to the the wave of the future, Xerox Corporation decided to jump into the mainframe computing business by acquiring Scientific Data Systems, which had been founded in 1961 and sold a series of inexpensive (for the era) mainframe computers optimised for scientific computation and support of real-time and online operation. At the time, the computing market in the U.S. was described as “IBM and the Seven Dwarves”, with the dwarves being Burroughs, Univac, NCR, Control Data, Honeywell, General Electric, and RCA. Xerox hoped to grow the market to become an eighth dwarf.

This was not to be. They bought at the very top of the market, and with the recession, inflation, aerospace collapse, and oil shocks of the early years of the Souring Seventies, the renamed Xerox Data Systems fell on hard times, and Xerox shut down the division in 1975, writing off hundreds of millions of dollars of investment. Honeywell acquired rights to the hardware and software and provided support for installed systems into the 1980s.

The Xerox Sigma dual computer installation at San Antonio Gas and Electric was seen as an exemplar of real-time system management and online interaction, including graphic interfaces.

The video states the price of a Sigma 9 mainframe in 1971 as “176 million dollars”. That’s a tad (three orders of magnitude) high. The actual purchase price was US$ 176,000 in 1971, which is around 1.3 million in today’s ironic BidenBucks.


I spent some time with an SDS 910, my one and only experience punching short binary programs into paper tape with a Flexowriter. My memories of it are fuzzy, but it may have been donated to our university by a Texas oil company. As I recall it’s only peripherals were a paper tape reader/punch and a typewriter terminal, plus a standalone Flexowriter

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