Apple DOS is the disk operating system used on Apple II computers from late 1978 through early 1983, when it was superseded by ProDOS. It had three major releases, DOS 3.1, DOS 3.2, and DOS 3.3, each followed by a minor bug fix release, though only the DOS 3.2 minor release received its own version number, 3.2.1, and the best known and most used version was DOS 3.3 in its 1980 and 1983 releases. Before DOS 3.1 was released, Apple users had to rely on audio cassette tapes for data storage and retrieval. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
Facts
Classification
LicenseProprietary (Closed Source) 1 FAQs
Why was the first Apple DOS called DOS 3.1 instead of DOS 1.0?
The name came from the author's own revision counter: the code was at revision 2.8 when Apple renamed it DOS 3.0 for beta testing and then 3.1 for release.
The number came from a revision counter kept by Paul Laughton, who wrote the system. Each time he recompiled the code he raised the counter, starting at 0.1 and rolling over to the next whole number after .9. The first listing he gave Apple was revision 2.8. Apple would not call it DOS 2.8, so it was renamed DOS 3.0 and used for beta testing. When Apple shipped the system for review it was raised to 3.1 to show the code had changed since the beta. DOS 3.0 itself was never released to the public, so DOS 3.1 shipped with the first Disk II drives sent to Apple dealers.
Connections
In Field
Source Wikipedia: Apple DOS
Licensed Under
In the Other Atlases
Developed By
Also in Business Atlas: the developer of this subject.
Sources
1. Wikipedia: Apple DOS
Lead section, opening sentence
Apple DOS is the disk operating system for the Apple II computers from late 1978 through early 1983. It was superseded by ProDOS in 1983.
Lead section, cassette tape sentence
Prior to the release of Apple DOS 3.1, Apple users had to rely on audio cassette tapes for data storage and retrieval.
History section, abandonment sentence
Apple abandoned this iteration of DOS in 1983, when Apple DOS was entirely replaced by ProDOS.
Infobox, License field
Apple Software License Agreement
In Field: Operating Systems, Lead sentence
Apple DOS is the disk operating system for the Apple II computers from late 1978 through early 1983. It was superseded by ProDOS in 1983. Apple DOS has three major releases: DOS 3.1, DOS 3.2, and DOS 3.3; each one of these three releases was followed by a seco
View the Source2. Wikidata: Apple DOS
- Wikidata Q621234, class allow-list match (w-wdresolver-0926)
- Wikidata Q621234 P577 (publication/release date) claim -> 1978; checked 2026-09-28
View the SourceReader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.