!!! Overview [{$pagename}] ([MVS]), was the most commonly used [Operating System] on the System/370 and System/390 [IBM] [mainframe] computers. [{$pagename}] was developed by [IBM], but is unrelated to IBM's other [mainframe] [Operating System], e.g., [VSE], [VM], [TPF]. First released in [1974|Year 1974], [{$pagename}] was extended by program products with new names multiple times: * first to MVS/SE (MVS/System Extensions),NB 1 * next to MVS/SP (MVS/System Product) Version 1, * next to MVS/XA (MVS/eXtended Architecture), * next to MVS/ESA (MVS/Enterprise Systems Architecture), * then to OS/390 and * finally to [z/OS|zOS] (when 64-bit support was added with the [zSeries] models). [IBM] added [UNIX] support (originally called OpenEdition [MVS]) in [MVS]/SP V4.3 and has obtained [POSIX] and [UNIX]™ certifications at several different levels from [IEEE], X/Open and [The Open Group]. The MVS core remains fundamentally the same [Operating System]. By design, [Applications] written for [MVS] run on [z/OS|zOS] without modification. !! More Information There might be more information for this subject on one of the following: [{ReferringPagesPlugin before='*' after='\n' }]