Apple DOS 3.1: Release Details

Apple DOS 3.1
Source: apple2history.org – Apple DOS 3.1

When Apple Computer introduced the Apple II in 1977, the computer was lacking a disk drive and disk operating system (DOS). Apple co-founder Steve Wozniak had designed the Apple Disk II controller, but co-founder Steve Jobs decided to outsource the task of creating a DOS.

Apple considered using Digital Research’s CP/M, but Wozniak sought an operating system that was easier to use. On April 10, 1978, Apple signed a $13,000 contract with Shepardson Microsystems to write a DOS and deliver it within 35 days.

The result was Apple DOS 3.1, which was publicly released on June 1, 1978. It was the first disk-based operating system for any Apple computer. However, it was quickly replaced by DOS 3.2 in 1979.

It’s worth noting that there were no official versions of Apple DOS 1 or 2. Versions 0.1 through 2.8 were serially enumerated revisions during development, which might as well have been called builds 1 through 28. Apple DOS 3.0, a renamed issue of version 2.8, was never publicly released due to bugs. Apple also published no official documentation until release 3.2.

Today, Apple DOS 3.1 is 45 years old and while it may not be in use anymore, it was an important milestone in the development of Apple’s computer systems.

ReleasedJune 1, 1978 – 45 years ago
System RequirementsApple II
DistributionFloppy disk

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