OS4000
| Developer | GEC Computers Ltd. |
|---|---|
| Written in | Babbage |
| Working state | No further development, but still supported |
| Source model | Closed source |
| Initial release | 1977 |
| Latest release | 6.5 / 1993? |
| Marketing target | Minicomputer, Process control, Real time, multi-user, Time-sharing, Batch processing, Data communications |
| Available in | English (UK) |
| Platforms | GEC 4000 series |
| Kernel type | Hardware and Firmware |
| Default user interface | CLI - OS4000 JCL |
| License | Proprietary |
OS4000 is a proprietary operating system introduced by GEC Computers Limited in 1977 as the successor to GEC DOS, for its range of GEC 4000 series 16-bit, and later 32-bit, minicomputers. OS4000 was developed through to late 1990s, and has been in a support-only mode since then.