Time Sharing Operating System, or
TSOS, was an
operating system for
RCA mainframe computers of the
Spectra 70 series. TSOS was originally designed in 1968 for the Spectra 70/46, a modified version of the 70/45. TSOS quickly evolved into the
Virtual Memory Operating System (
VMOS) by 1970. VMOS continued to be supported on the later RCA 3 and RCA 7 computer systems.