| Operating system | Developer | First release | License |
|---|---|---|---|
| Michigan Terminal System | University of Michigan | 1967 | — |
| MUSIC/SP | McGill University | 1972 | — |
| MVS | IBM | 1974 | proprietary license |
| OS/VS1 | IBM | — | — |
| VM | IBM | — | — |
| VM-CP | IBM | — | — |
| VOS3 | Hitachi | — | — |
| VP/CSS | IBM, National CSS | — | — |