UNIVAC Series 90

The Univac Series 90 was a family of mainframe class computer systems from UNIVAC first introduced in 1973. The low end family members included the 90/25, 90/30 and 90/40 that ran the OS/3 operating system. The intermediate members of the family were the 90/60 and 90/70, while the 90/80 was the high end system. The 90/60 through 90/80 systems all ran the Univac’s virtual memory operating system, VS/9.

The Series 90 systems were the replacement for the UNIVAC 9000 series of low end, mainframe systems marketed by Sperry Univac during the 1960s. The 9000 series systems were byte-addressable machines with an instruction set that was compatible with the IBM System/360. The family included the 9200, 9300, 9400, and 9480 systems; the 9400 and 9480 ran a real memory operating system called OS/4. As Sperry moved into the 1970s, they expanded the 9000 family with the introduction of the 9700 system in 1971. They were also developing a new real memory operating system for the 9700 called OS/7.

In September 1971, the RCA Corporation announced that it was abandoning the computer industry and Sperry acquired RCA’s Computer division. RCA had marketed the Spectra 70 Series (70/15, 70/25, 70/35, 70/45, 70/46, 70/55, 70/60, 70/61) that were compatible with The IBM System/360 series and the RCA Series (RCA 2, 3, 6, 7) competing against the IBM System/370. These systems all ran RCA’s real memory operating systems, DOS and TDOS. RCA’s virtual memory systems, the Spectra 70/46 and 70/61 and the RCA 3 and 7, could also run their Virtual Memory Operating System, VMOS. VMOS was originally named TSOS (Time Sharing Operating System), but was renamed in order to expand the system beyond the time sharing market. TSOS was the first mainframe, demand paging, virtual memory operating system on the market. At the time, IBM was in the process of transforming OS/360 to a virtual memory system through the OS/VS1 and OS/VS2 (SVS) operating systems, on the way to the subsequent release of MVS.

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