| Oasis Software | No tapes | No tapes | No books | No hardware |
| Omega | Tapes | No tapes | No books | No hardware |
| Omega Soft | No tapes | No tapes | No books | No hardware |
| Orbyte Software | Tapes | No tapes | No books | No hardware |
| Orme Electronics | No tapes | No tapes | No books | No hardware |