RCA Spectra 70

The RCA Spectra 70 was a line of electronic data processing (EDP) equipment manufactured by the Radio Corporation of America’s computer division beginning in April 1965. The Spectra 70 line included several CPU models, various configurations of core memory, mass-storage devices, terminal equipment, and a variety of specialized interface equipment.

The system architecture and instruction-set were largely compatible with the non-privileged instruction-set of the IBM System/360. While this degree of compatibility made some interchange of programs and data possible, differences in the operating system software precluded transparent movement of programs between the two systems.

Four models of the Spectra 70 CPU were offered in 1965, ranging from a small system (70/15) to the large scale (70/55). Some of the main features were:

These systems all ran RCA's real-memory operating systems, DOS and TDOS. The systems that supported virtual memory, the Spectra 70/46 and 70/61 and the later RCA 3 and 7, could also run the RCA's Virtual Memory Operating System (VMOS). VMOS was originally named TSOS (Time Sharing Operating System), but was renamed to expand the system beyond the time-sharing market. TSOS was the first mainframe, demand paging, virtual memory operating system on the market. The Spectra series was later supplemented by the RCA Series (RCA 2, 3, 6, 7), which competed against the IBM System/370. The English Electric System 4 mainframes — the 4-10, 4-30, 4-50, 4-70 and the time-sharing 4-75 — were essentially RCA Spectra 70 clones of the IBM System/360 and 370 range.

The RCA Model 70/15 was a 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.

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.

...
Wikipedia