Commodore DOS, aka CBM DOS, was the disk operating system used with Commodore's 8-bit computers. Unlike most other DOS systems before or since, CBM DOS was integrated in the internal ROM of the floppy disk drives(as well as the very few hard disk models Commodore made for its 8-bit range), not loaded from disk into the computer's own RAM at startup.

Versions of CBM DOS

• 1.0
• X.Y
• 2.6 – the most common version due to its use in the 1541 floppy disk drive
• S.T

References

• Immers, Richard; Neufeld, Gerald G. (1984). Inside Commodore DOS. The Complete Guide to the 1541 Disk Operating System. DATAMOST, Inc & Reston Publishing Company, Inc. (Prentice-Hall). ISBN 0-8359-3091-2.