Apple DOS

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Apple DOS is a series of disk operating systems developed by Apple for the Apple II personal computers. It was a short-lived, but very popular operating system, launched in 1978 and retired in early 1983.

Apple DOS had only three public releases: 3.1, 3.2 and 3.3, all followed by second versions with minor bug-fixes, of which only DOS 3.2.1 received its own version number among the bug-fixing releases. Versions 1 and 2 were internal versions, and version 3 was not launched because of some serious bugs. Apple DOS was launched so that the users could use floppy disks. Until then (which was for about an year since Apple II was launched), users were stuck using the slow and unreliable cassette tapes.

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DOS 3.1

DOS 3.1 was written mostly by Steve Woznia, Randdy Wigginton and Paul Laughton. The OS itself was quite hated by programmers, because Apple didn't supply any form of official documentation, and it was strongly tied to Integer BASIC.

This version gave the user about 113 KB of effective storage for each disk side, of which it was using 10 KB. DOS 3.1 was not able to access both sides of the disk, but the user could flip it if required.

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DOS 3.2

DOS 3.2 was released in 1979 and had many significant features. As it would run on the Apple II Plus, it had several changes in the booting procedure, especially as Apple II+'s ROM could automatically boot from a disk when powered on. It was no longer tied to Integer BASIC, but to a newer and better version, the Applesoft BASIC.

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DOS 3.3

1980 saw a new version of Apple DOS, the DOS 3.3. DOS 3.3 fixed a number of bugs, and added support for greater storage capacity. The users could now access 130 KB of storage on each disk side, although sacrificing some backwards compatibility. This was improved with MUFFIN, which could migrate DOS 3.2 files and programs to the new version. NIFFUM, a program that would do the reverse, was also launched, but not by Apple, and it was not officially supported by anyone either.

Apple gave an exclusive reselling license to Syndicomm.

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