VSE (operating system)
VSEn (Virtual Storage Extended) is an operating system for IBM mainframe computers, the latest one in the DOS/360 lineage, which originated in 1965. It is less common than z/OS and is mostly used on smaller machines.
| Developer | 21st Century Software (previously IBM) |
|---|---|
| OS family | DOS/360 and successors |
| Working state | Current |
| Source model | Closed source |
| Latest release | 6.3 / May 17, 2022 |
| Marketing target | IBM mainframe computers |
| License | Proprietary |
| Official website | 21cs |
| History of IBM mainframe operating systems |
|---|
DOS/VSE was introduced in 1979 as a successor to DOS/VS; in turn, DOS/VSE was succeeded by VSE/SP version 1 in 1983, and VSE/SP version 2 in 1985. In the late 1980s, there was a widespread perception among VSE customers that IBM was planning to discontinue VSE and migrate its customers to MVS instead, although IBM relented and agreed to continue to produce new versions of VSE. In February 2005, IBM announced z/VSE as successor to VSE/ESA 2.7, which was named to reflect the new System z branding for IBM's mainframe product line. In June 2021, 21st Century Software Inc announced that it had licensed the z/VSE source code from IBM with the intention of developing new versions of the operating system. As part of this transfer, z/VSE was renamed to VSEn.