11 Facts About Apple DOS


Apple DOS is the family of disk operating systems for the Apple II series of microcomputers from late 1978 through early 1983.

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On 10 April 1978 Apple signed a $13,000 contract with Shepardson Microsystems to write a DOS and deliver it within 35 days.

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Apple DOS provided detailed specifications, and early Apple DOS employee Randy Wigginton worked closely with Shepardson's Paul Laughton as the latter wrote the operating system with punched cards and a minicomputer.

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Apple DOS never offered a utility to copy in the other direction.

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On top of the File Manager API, the main Apple DOS routines are implemented which hook into the machine's BASIC interpreter and intercept all disk commands.

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Apple DOS recognizes these types for catalog listings only, and there are no direct ways to manipulate these types of files.

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Process of loading Apple DOS involves a series of very tiny programs, each of which carries the loading process forward a few steps before passing control to the next program in the chain.

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Original Apple DOS II included BASIC interpreter in ROM known originally as Apple DOS BASIC and later as Integer BASIC.

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Shortly after ProDOS came out, Apple withdrew permission from third parties to redistribute DOS 3.

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Commercial games usually did not use Apple DOS, instead having their own custom disk routines for copy protection purposes as well as for performance.

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Later, programmers outside Apple DOS rewrote the File Manager routines to avoid making the extra copy for most sectors of a file; RWTS was instructed to read or write sectors directly to or from main memory rather than from a disk buffer whenever a full sector was to be transferred.

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