![]() |*| Op Code | R | X | Reference address |īits 1-7 contain the operation code (opcode)īits 8-11 encode a register operand (0:15)īits 12-14 encode an index register (1:7). The format for memory-reference instructions for the 32-bit Sigma systems is as follows: The various other system components came from other user sites, such as Marquette, Samford and Xerox/Dallas. Keith Calkins made the Sigma 9 functional for the museum in 2012/13 and brought up the CP-V operating system in Dec. In February 1990, Andrews University via Keith Calkins sold and delivered it to Applied Esoterics in Flagstaff, Arizona. 1985 when Andrews University purchased it and took it to Michigan. That Sigma 9 CPU was at the University of Southern Mississippi until Nov. In 2011, the Living Computer Museum in Seattle, Washington acquired a Sigma 9 from a service bureau (Applied Esoterics/George Plue Estate) and has made it operational. Sigma 9 computers were still in service in 1993. The Sigma 9 may hold the record for the longest lifetime of a machine selling near the original retail price. which continued support for the Sigma line for a time.Īn XDS Sigma 9 at the Living Computer Museum, Seattle, Washington, US, 2014 In 1975, Xerox sold its computer business to Honeywell, Inc. The Xerox 500 series computers, introduced starting in 1973, are compatible upgrades to the Sigma systems using newer technology. Although this is a trivial amount of memory in today's technology, Sigma systems performed their tasks exceptionally well, and few were deployed with, or needed, the maximum 128K Word memory size. Maximum memory is limited by the length of the instruction address field of 17 bits, or 128K Words (512K Bytes). For example, the Sigma 5 base memory is 16K 32-Bit words (64K Bytes). Memory size increments for all SDS/XDS/Xerox computers are stated in kWords, not kBytes. At the time, the only competition for the Sigma 7 was the IBM 360. The first machines in the series are the 16-bit Sigma 2 and the 32-bit Sigma 7 the Sigma 7 was the first 32-bit computer released by SDS. ![]() The SDS Sigma series is a series of third generation computers that were introduced by Scientific Data Systems of the United States in 1966. Front panel of the SDS Sigma 5 computer at the Computer History Museum ![]()
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