Editing KeyKOS (section)

{{Infobox OS
| name = KeyKOS
| logo = <!-- Filename only: no wikilink, Image: or File: -->
| logo size = 
| logo caption = 
| logo alt = 
| screenshot = <!-- Filename only: no wikilink, Image: or File: -->
| caption = 
| developer = [[Tymshare]] (Norm Hardy, Bill Frantz, Charlie Landau)<br/>[[McDonnell Douglas]]<br/>Key Logic
| family = [[Capability-based security|Capability-based]]
| working state = Discontinued
| source model = <!-- "Open-source", "Closed-source", or "Source-available" -->
| released = {{Start date and age|1977}}<!-- If known, add |mm|dd|df=yes -->
| latest release version = Final
| latest release date = {{Start date and age|1988}}<!-- If known, add |mm|dd|df=yes -->
| marketing target = Research
| programmed in = [[C (programming language)|C]]
| language = English
| update model = Compile from [[source code]]
| supported platforms = [[IBM System/370|S/370]] [[IBM mainframe|mainframe]]
| kernel type = [[Microkernel]]
| userland = 
| ui = [[Command-line interface]]
| license = 
| preceded by = [[GNOSIS]]
| succeeded by = [[EROS (microkernel)|Extremely Reliable Operating System]] (EROS), CapROS, Coyotos
| website = {{URL|cap-lore.com/CapTheory/KK}}
}}
'''KeyKOS''' is a [[Persistence (computer science)|persistent]], pure [[Capability-based security|capability]]-based [[Capability-based operating system|operating system]] for the [[IBM]] [[IBM System/370|S/370]] [[IBM mainframe|mainframe]] [[computer]]s. It allows [[Emulator|emulating]] the environments of [[VM (operating system)|VM]], [[MVS]], and Portable Operating System Interface ([[POSIX]]). It is a predecessor of the [[EROS (microkernel)|Extremely Reliable Operating System]] (EROS), and its successor [[operating system]]s, CapROS, and Coyotos. KeyKOS is a [[nanokernel]]-based operating system.<ref>[http://www.cis.upenn.edu/~KeyKOS/NanoKernel/NanoKernel.html The KeyKOS Nanokernel Architecture] {{webarchive|url=https://web.archive.org/web/20110621235229/http://www.cis.upenn.edu/~KeyKOS/NanoKernel/NanoKernel.html |date=2011-06-21}}</ref>

In the mid-1970s, development of KeyKOS began at [[Tymshare]], Inc., under the name [[GNOSIS]]. In 1984, [[McDonnell Douglas]] (MD) bought Tymshare. A year later MD spun off Key Logic, which bought GNOSIS and renamed it ''KeyKOS''.<ref>{{Cite web |url=http://www.cap-lore.com/CapTheory/KK/EKK.html |title=Roots of KeyKOS |website=Cap-lore.com}}</ref>