| name | type | date isolation | country of isolation | continent of isolation | country of origin | continent of origin | Operating system affected | Developer |
|---|---|---|---|---|---|---|---|---|
| Form (computer virus) | 06/1990 | Switzerland | Europe | Switzerland | Europe | DOS | ||
| Ontario (computer virus) | 07/1990 | Canada | Americas | Canada | Americas | DOS | ||
| AntiCMOS | 01/1994 | Slovenia | Europe | China | Asia | DOS | ||
| Alabama (computer virus) | 10/1989 | Israel | Asia | Israel | Asia | DOS | ||
| Alcon (computer virus) | 1997 | DOS |