The Univac 90/60 series computer was a mainframe class computer manufactured by Sperry Corporation as a competitor to the IBM System 360 series of mainframe computers. The 90/60 used the same instruction set as the 360, although the machines themselves were not compatible with each other; programs written for one would have to be recompiled for the other, as at the time they were developed, the concept of an operating system being portable separately from the computer system it ran on was unheard of.
The 90/60 was originally developed by RCA corporation as the Spectra series of computers. After RCA decided to get out of the computer business due to stunning losses, it sold most of its computer and peripheral lines to Sperry; a few were sold to Singer Corporation.
The 90/60 series was an enhanced workalike to the 360, as it included special features which were not available on IBM hardware until later in the System 370 series, including virtual memory, demand paging of applications, and good support for terminal-based users (IBM's offerings on 360 mainframes provided weak support for interactive computing).
The operating systems which ran on the 90/60 included RCA's TSOS operating system and Sperry's own VS/9 operating system. The 90/60 was superseded by the UNIVAC 90/70 (a workalike for IBM's System 370 and the UNIVAC 90/80.