| Answer | Crossword Clue |
|---|---|
| UNIX | Pioneering computer operating system |
| UNIX | Computer operating system |
| LINUX | Computer operating system |
| MSDOS | Computer operating system |
| UNIX | Popular computer operating system |
| DOS | Old computer operating system |
| DOS | Computer operating system: acron. |
| UNIX | Longtime computer operating system |
| UNIX | Multiuser computer operating system |
| UNIX | Early computer operating system |
| UNIX | Computer workstation operating system |
| MSDOS | Computer operating system of old |
| UNIX | Widely used computer operating system |
| UNIX | Computer operating system since the '60s |
| UNIX | Computer operating system developed at Bell Labs |
| UNIX | Computer operating system developed by Bell Labs |
| LINUX | Computer operating system with a penguin mascot |
