VM (operating system)
| z/VM | |
|---|---|
| Developer | IBM |
| OS family | VM family |
| Working state | Current |
| Source model | 1972–1986 Open source, 1977–present Closed source |
| Initial release | 1972 |
| Latest release | IBM z/VM V7.4 / September 20, 2024 |
| Marketing target | IBM mainframe computers |
| Available in | English |
| Supported platforms | System/370, System/390, IBM Z |
| License | 1972–1981 Public domain, 1976–present Proprietary |
| Official website | www |
| History of IBM mainframe operating systems |
|---|
VM, often written VM/CMS, is a family of virtual machine operating systems used on IBM mainframes including the System/370, System/390, IBM Z and compatible systems. It replaced the older CP-67 that formed the basis of the CP/CMS operating system. It was first released as the free Virtual Machine Facility/370 for the S/370 in 1972, followed by chargeable upgrades and versions that added support for new hardware.
VM creates virtual machines into which a conventional operating system may be loaded to allow user programs to run. Originally, that operating system was CMS, a simple single-user system similar to DOS. VM can also be used with a number of other IBM operating systems, including large systems like MVS or VSE, which are often run on their own without VM. In other cases, VM is used with a more specialized operating system or even programs that provided many OS features. These include RSCS and MUMPS, among others.