RCA Spectra 70
The RCA Spectra 70 is a line of electronic data processing (EDP) equipment that was manufactured by the Radio Corporation of America’s computer division beginning in April 1965.
Competition in the mainframe market was fierce, and in 1971 the company sold the computer division and the Spectra 70 line to Sperry Rand, taking a huge write down in the process.
Five models of the Spectra 70 CPU were announced around 1965, ranging from a small system (70/15) to the large-scale (70/55).
TSOS was the first mainframe, demand paged, virtual memory operating system on the market.
The RCA Model 70/15 (1965)[2] was a discrete[7] small-scale processor that could still support a variety of applications.
Memory limitations and relatively low processing speed made its use as a stand-alone computer system somewhat impractical.
It implemented a small subset of 25 instructions of the full Spectra 70 architecture,[3]: p.10 and was not downward compatible with the rest of the range.
The 70/15 was often used as a satellite processor for larger systems or used as an intelligent terminal for remote job entry.
Typical applications of a satellite processor would include card-to-tape conversion, card/tape-to-printer report generation, tape-to-card punching, input pre-processing and verification, or tab-shop tasks like file sorting, merge, and data selection.
Like the Model 15, it implemented a (slightly larger) subset of 31 instructions of the full range architecture.
[8] The RCA Model 70/35 was the fifth in the series of Spectra computers that was announced in September 1965 (first delivery in 1966).
[9][10] It was a medium-scale computer combining third-generation technology (including integrated circuits)[7] and speed in an efficient low-cost data system.
The students were learning the fundamentals of programming and system operation with "hands-on" experience.
A floating-point processor was available as an option and the 70/45 was considered suitable for commercial, scientific, communications, and real-time applications.
The memory cycle time was 1.44 microseconds to access two bytes (one half word) of information.
Although these computers were fast and reliable they came too late to impact the lead of the IBM 360 product line.
