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. At the time, the only competition for the Sigma 7 was the IBM 360. Memory size increments for all SDS/XDS/Xerox computers are …

The 32-bit Sigma and Xerox Computers The SDS Sigma 7 was the first 32-bit computer which SDS produced. SDS claimed that it was the only computer (then available) to handle all computer applications effectively (i.e. Scientific, Commercial, and Real-time). It was announced March 15, 1966, delivered yet that year (on-time) and was hailed as ...

SIGMA 7, the largest computer in the Sigma family, is specifically designed for real-time operations in a time-sharing environment. It can simultaneously perform real-time, conver- sational time-sharing, general-purpose, and high-speed input/output operations, individually or in any combination.

The Sigma systems were a series of computers first introduced by Scientific Data Systems (SDS) in 1966. The first machines in the series were the Sigma 2 and Sigma 7, which, at the time of their release, were competitors to the IBM System/360 family of computers. When SDS was purchased by Xerox in 1969, the firm was renamed Xerox Data Systems ...

Various versions of the Sigma 7 followed, including the cut-down Sigma 5 and re-designed Sigma 6. The Xerox Sigma 9 was a major re-design with instruction lookahead and other advanced features, while the Sigma 8 and Sigma 9 mod 3 were low-end machines offered as a migration path for the Sigma 5.

Historically, Xerox (then Scientific Data Systems) introduced the Sigma series as a direct competitor to the IBM System/360, with the promise of "at least two times more computations per dollar than any other machine in the industry." This claim was overly ambitious, but …

The company was purchased by Xerox in about 1970, and SDS became Xerox Data Systems, and the machine was then called the XDS Sigma 7. The machine was a 32-bit processor, which was quite advanced for its time. It was reliable, but we had a fair amount of trouble with the operating system, which was quite new.

Not too many years after we got our Sigma 7, Xerox came out with a new and improved version. Most of the optional Sigma 7 features were standard, the system was faster, and it even cost less.

This manual contains information necessary to install, operate, and maintain the Sigma 7 Computer System manu-factured by Xerox Data Systems, EI Segundo, California. Section I provides a general physical and functional descrip-tion.

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