# Time Sharing Operating System

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This article is about the operating system by RCA. For the concept of time-sharing in computing, see [Time-sharing](/source/Time-sharing).

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Operating system

Time Sharing Operating System (TSOS) Developer Radio Corporation of America (RCA) OS family Not Applicable Working state Discontinued Source model Unknown Initial release 1968; 58 years ago (1968) Supported platforms RCA Spectra 70 series mainframe computers Default user interface Command-line interface License Proprietary

**Time Sharing Operating System**, or **TSOS**, is a discontinued [operating system](/source/Operating_system) for [RCA](/source/RCA_Corporation) [mainframe computers](/source/Mainframe_computer) of the [Spectra 70](/source/RCA_Spectra_70) series. TSOS was originally designed in 1968 for the Spectra 70/46, a modified version of the 70/45.[1] 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.[2]

RCA was in the computer business until 1971 when it sold its computer division to [Sperry Corporation](/source/Sperry_Corporation). Sperry renamed TSOS to [VS/9](/source/VS%2F9) and continued to market it into the early 1980s. In the mid seventies, an enhanced version of TSOS called [BS2000](/source/BS2000) was offered by the German company [Siemens](/source/Siemens).

While Sperry – now [Unisys](/source/Unisys) – discontinued [VS/9](/source/VS%2F9), the [BS2000](/source/BS2000) variant, now called BS2000/OSD, is still offered by [Fujitsu](/source/Fujitsu) and used by their mainframe customers primarily in Germany and other European countries.

As the name suggests, TSOS provided [time sharing](/source/Time_sharing) features. Similar to [CTSS](/source/Compatible_Time-Sharing_System) it provided a common user interface for both time sharing and [batch](/source/Batch_processing), which was a big advantage over [IBM](/source/IBM)'s [OS/360](/source/OS%2F360) or its successors [MVS](/source/MVS), [OS/390](/source/OS%2F390) and [z/OS](/source/Z%2FOS).

## See also

- [Timeline of operating systems](/source/Timeline_of_operating_systems)

## References

1. **[^](#cite_ref-TSOS_1-0)** Radio Corporation of America (1968). [*Spectra 70 Time Sharing Operating System Information Manual*](http://bitsavers.trailing-edge.com/pdf/rca/spectra70/tsos/79-00-513_TSOS_InfoMan_Mar68.pdf) (PDF).

1. **[^](#cite_ref-spectra_2-0)** RCA Computer Systems Division (Dec 1970). [*RCA Series Information Manual*](http://bitsavers.trailing-edge.com/pdf/rca/spectra70/BF-000-1-00_SPECTRA_InfoMan_Dec70.pdf) (PDF). pp. 4–17.

## External links

- [TSOS manuals at Bitsavers](http://bitsavers.trailing-edge.com/pdf/rca/spectra70/tsos/)

v t e Time-sharing operating systems Time-sharing system evolution BBN Time-Sharing System Berkeley Timesharing System Burroughs MCP CDC Kronos Compatible Time-Sharing System (CTSS) COS CP/CMS Cray Time Sharing System (CTSS) DTSS EMAS ITS LTSS MCTSS MTS Multics MUSIC/SP NLTSS NOS NOS/VE OpenVMS ORVYL and WYLBUR OS4000 Pick RAX RSTS/E TENEX TSO TSOS TOPS-10 TOPS-20 TSS TSS/8 Unix UTS VM VP/CSS VPS/VM VS/9 WAITS Category

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Adapted from the Wikipedia article [Time Sharing Operating System](https://en.wikipedia.org/wiki/Time_Sharing_Operating_System) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Time_Sharing_Operating_System?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.