Apple Pascal

Apple Pascal was an implementation of UCSD Pascal, the P- code of the University of California, San Diego (UCSD ) for the Apple II Pascal was very popular in the 1970s and early 1980s; therefore derived from UCSD Pascal II.1 a variant for the Apple II. Two UCSD students, Mark Allen and Richard Gleaves, developed in the summer of 1978, an interpreter for the microprocessor used in the 6502 Apple II, which later became the basis for Apple Pascal, which was published in 1979 and for five years was a product of Apple.

Release Level

UCSD Pascal was developed by Roger T. Sumner at the Institute for Information Systems UCSD, there are five versions have been published:

  • Version I.3 August 1977
  • Version I.4 January 1978
  • Version I.5 September 1978 ( source code released)
  • Version II.0 February 1979
  • Version II.1 1979

Apple Pascal four versions have been released:

  • Version 1.0 1979 ( based on UCSD Pascal II.1 )
  • Version 1.1 1980
  • Version 1.2 1983
  • Version 1.3 1984

From version 1.2 128K systems were only supported yet.

Economic Importance

The direct economic impact of the Apple Pascal operating system has little or no:

  • There were few professional applications. Popularity has possibly attained the ADImens database, also known as the ADI proFIT. ADImens was later ported to the Atari ST. The database was developed by the Karlsruhe company ADI GmbH Company for application programming, data analysis, and industrial use of computers (later adisoft AG, today ADI Innovation AG ).
  • Indirectly but Pascal was the basis for the programming of the Lisa and later the Mac OS up to version 9.2.2 Mac OS. The operating system of the Mac was released as Pascal code for those interested in a book, and thus visible to everyone. Programming in Pascal with the strong type checking was a major reason for the high stability of the early Mac OS. Mac OS X later built on FreeBSD and was written like all Unix -like operating systems in C, C and assembler.

Language scope

Developed by Niklaus Wirth standard was extended to include some language elements in UCSD Pascal, for example, to unit commands (unit read, write unit, unit status) to communicate directly with the connected hardware. In order to economize scarce memory space, it was possible to segment the program. Apple Pascal language differs in scope only slightly from UCSD Pascal.

P-code machine License Apple Lisa
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