Editing Stratus VOS (section)

==History==
VOS was designed from its inception as a high-security transaction-processing environment tailored to fault-tolerant hardware.<ref name="Stratus FAQ">{{cite web|url=http://ftp.stratus.com/vos/faq.txt |archive-url=https://web.archive.org/web/20150502135022/http://ftp.stratus.com/vos/faq.txt |url-status=dead |archive-date=2015-05-02 |format=TXT |title=Article 5121 in comp.sys.stratus |website=Ftp.stratus.com |accessdate=2016-05-21}}</ref> It incorporates much of the design experience that came out of the MIT/Bell-Laboratories/General-Electric (later Honeywell) [[Multics]] project.

In 1984, Stratus added a [[UNIX System V]] implementation called Unix System Facilities (USF) to VOS, integrating Unix and VOS at the [[kernel (operating system)|kernel]] level.<ref>{{cite news |title=Stratus offers Unix implementation for mainframes |newspaper=Computerworld |date=12 November 1984 |page=86 |url=https://books.google.com/books?id=CR4n14lZ9_wC&pg=RA1-PA86}}</ref>

In recent years,{{when|date=January 2016}} Stratus has added [[POSIX]]-compliance, and many open source packages can run on VOS.<ref name="VOS POSIX">{{cite web|url=http://ftp.stratus.com/vos/posix/posix.html |archive-url=https://web.archive.org/web/20160402160843/http://ftp.stratus.com/vos/posix/posix.html |url-status=dead |archive-date=2016-04-02 |title=POSIX-based Open-Source Software for VOS and OpenVOS |website=Ftp.stratus.com |date=2015-04-24 |accessdate=2016-05-21}}</ref>

Like competing proprietary operating systems, VOS has seen its market share shrink steadily in the 1990s, and early 2000s.<ref>{{Cite book |title=Modernizing Legacy Systems: Software Technologies, Engineering Processes, and Business Practices |first1=Robert C. |last1=Seacord |first2=Daniel |last2=Plakosh |first3=Grace A. |last3=Lewis |publisher=Addison-Wesley |year=2003 |url=https://books.google.com/books?id=VRzHuzJS3IwC&pg=PA11 |page=11|isbn=9780321118844 }}</ref>