| Operating system | Developer | First release | License |
|---|---|---|---|
| Edos | The Computer Software Company | — | — |
| Group Control System | IBM | — | — |
| Special Real Time Operating System | IBM | — | — |
| UTS | Amdahl Corporation, UTS Global | 1981 | — |
| VPS/VM | Boston University | — | — |
| Operating system | Developer | First release | License |
|---|---|---|---|
| Edos | The Computer Software Company | — | — |
| Group Control System | IBM | — | — |
| Special Real Time Operating System | IBM | — | — |
| UTS | Amdahl Corporation, UTS Global | 1981 | — |
| VPS/VM | Boston University | — | — |