| D. Bradburn | No tapes | No tapes | No books | No hardware |
| D. Bruce Electronics | No tapes | No tapes | No books | No hardware |
| DCP | No tapes | No tapes | No books | No hardware |
| D. C. Roberts | No tapes | No tapes | No books | No hardware |
| D. Cordiner | No tapes | No tapes | No books | No hardware |
| D. Fritsch | No tapes | No tapes | No books | No hardware |
| D. Hutchinson | No tapes | No tapes | No books | No hardware |
| DJL Software | Tapes | No tapes | No books | No hardware |
| dK'tronics | Tapes | Tapes sorted by code | No books | Hardware |
| D. R. Horne | No tapes | No tapes | No books | No hardware |
| D. Wale | No tapes | No tapes | No books | No hardware |
| D. Warrington | No tapes | No tapes | No books | No hardware |
| Data-assette | Tapes | No tapes | No books | No hardware |
| Database Software | Tapes | No tapes | No books | No hardware |
| Datel | No tapes | No tapes | No books | Hardware |
| Dean Electronics | No tapes | No tapes | No books | Hardware |
| Digital Integration | Tapes | No tapes | No books | No hardware |
| Direco International | Tapes | No tapes | Books | No hardware |
| Docimodus | No tapes | No tapes | No books | No hardware |
| Doric Computer Systems | Tapes | No tapes | No books | No hardware |
| Downsway Electronics | No tapes | No tapes | No books | No hardware |
| Dunrobin Software | No tapes | No tapes | No books | No hardware |