Last Updated on: 10th November 2023, 04:43 pm
Apple DOS – a disk operating systems (DOS) for the Apple II series of microcomputers developed between 1978 and 1983. The Apple II series is a family of home computers, designed primarily by Steve Wozniak, manufactured by Apple Computer, and launched in 1977 with the original Apple II.
DOS 3.1 was the first shipping version of Apple II DOS. It was included with the first Disk II drives for the Apple II, in July 1978, in the form of the DOS 3.1 System Master disk. It was replaced with DOS 3.2 in February 1979.
DOS 3.1 has four software layers, each with increasing abstraction.:
– The low-level driver, written by Steve Wozniak, which do the heavy lifiting of actually operating the disk drive
– RWTS, short for Read/Write Track/Sector, which is a basic API for the low-level driver. It only supports four operations, SEEK (to a particular track), READ (a sector), WRITE (a sector), and FORMAT (the whole disk).
– The File Manager, which is the layer that implements a file system using the RWTS functions.
– The Main DOS Routines, which hook into the machine’s BASIC interpreter and intercept all disk commands. In addition to snooping all interactive input to the BASIC interpreter, it watches the output from BASIC for control sequences which denote DOS commands.