Apple Pascal
{{Short description|Programming system for Apple II and III}}
{{Infobox OS
| name = Apple Pascal
| screenshot = Apple Pascal 1.2.jpg
| caption = Apple Pascal for Apple II, version 1.2
| developer = Apple Computer
| family = UCSD Pascal
| source_model = Closed source
| working_state = Historic
| released = {{Start date and age|1979|08}}
| latest_release_version = 1.3 (Apple II)
1.1 (Apple III)
| latest_release_date = {{Start date and age|1984}}{{cite web|url=http://apple2info.net/index.php?title%3DApple_II_Pascal |title=Apple II Pascal - apple2info.net: Apple II Information |access-date=April 23, 2015 |url-status=dead |archive-url=https://web.archive.org/web/20150430033749/http://apple2info.net/index.php?title=Apple_II_Pascal |archive-date=April 30, 2015 }}
| kernel_type = Monolithic
| license = Apple Software License Agreement
| website =
|}}
Apple Pascal is an implementation of Pascal for the Apple II and Apple III computer series, based on UCSD Pascal.{{harvnb|Apple|1980|p=248}}
Just like other UCSD Pascal implementations, it ran on its own operating system (Apple Pascal Operating System,{{harvnb|Apple|1980|p=2}} a derivative of UCSD p-System with graphical extensions).
Originally released for the Apple II in August 1979, just after Apple DOS 3.2, Apple Pascal pioneered a number of features that would later be incorporated into DOS 3.3, as well as others that would not be seen again until the introduction of ProDOS.
The Apple Pascal software package also included disk maintenance utilities,{{harvnb|Apple|1980|p=183}} and an assembler{{harvnb|Apple|1980|p=134}} meant to complement Apple's built-in "monitor" assembler. A FORTRAN compiler (written by Silicon Valley Software of Sunnyvale, California) compiling to the same p-code as Pascal was also available.{{Cite web|url = http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Software/Languages/Apple%20II%20FORTRAN/Manuals/Apple%20FORTRAN%20Language%20Reference%20Manual.pdf|title = Apple Fortran Language Reference Manual|date = |access-date = |website = |publisher = }}
Comparison of Pascal OS with DOS 3.2
Apple Pascal Operating System introduced a new disk format.Apple Pascal was designed to take advantage of the then new 140K 5.25" floppy disks. Instead of dividing the disk into 256-byte sectors as in DOS 3.2, Apple Pascal divides it into "blocks" of 512 bytes each.{{harvnb|Apple|1980|p=25}} The p-System also introduced a different method for saving and retrieving files. Under Apple DOS, files were saved to any available sector that the OS could find, regardless of location. Over time, this could lead to file system fragmentation, slowing access to the disk. Apple Pascal attempted to rectify this by saving only to consecutive blocks on the disk.{{harvnb|Apple|1981|p=162}}
Other innovations introduced in the file system included the introduction of a timestamp feature. Previously only a file's name, basic type, and size would be shown. Disks could also be named for the first time.Under Apple DOS, disks can only be given a volume number. Apple Pascal disk volume names can be up to seven characters in length. See {{harvnb|Apple|1980|p=27}}
Limitations of the p-System included new restrictions on the naming of files.Apple DOS allowed filenames up to thirty characters long and any ASCII character could be used, Apple Pascal dropped the length to fifteen characters and allowed only letters, numbers and periods to be used. See {{harvnb|Apple|1980|p=30}}
Writing files only on consecutive blocks also created problems, because over time free space tended to become too fragmented to store new files. A utility called KRUNCH was included in the package to consolidate free space.{{harvnb|Apple|1980|p=49}}
The biggest problem with the Apple Pascal system was that it was too big to fit on one floppy disk. This meant that on a system with only one floppy disk drive, frequent disk swapping was needed. A system needed at least two disk drives in order to use the operating system properly.
Release history
| class="wikitable" |
| Platform
! Date ! OS |
|---|
| Apple II
| 1979 | Apple Pascal 1.0 |
| | 1980
| Apple Pascal 1.1 |
| | 1983
| Apple Pascal 1.2 |
| | 1985
| Apple Pascal 1.3 |
| Apple III
| 1981{{harvnb|Apple|1981|p=I}} | Apple Pascal 1.0 |
| | 1983{{harvnb|Apple|1983|p=I}}
| Apple Pascal 1.1 |
Sources
- {{cite book |last=Apple|date=1980 |title=Apple II Pascal Operating System Reference Manual |url=http://apple2info.net/images/2/24/Apple2Pascal_Operating_System_Ref.pdf |archive-url=https://web.archive.org/web/20150430033749/http://apple2info.net/images/2/24/Apple2Pascal_Operating_System_Ref.pdf |access-date=September 12, 2018|archive-date=2015-04-30 }}
- {{cite book |last=Apple|date=1981 |title=Apple III Pascal - Introduction, Filer and Editor|url=http://apple3.org/Documents/Manuals/Apple%20III%20Pascal%20-%20Introduction,%20Filer%20and%20Editor.pdf |access-date=September 12, 2018}}
- {{cite book |last=Apple|date=1983 |title=Apple III Update 1.1|url=http://apple3.org/Documents/Manuals/Apple%20III%20Pascal%201.1%20Update.PDF|access-date=September 12, 2018}}
- {{cite book |last=Hyde |first=Randall |title=p-Source: Guide to Apple Pascal System |publisher=Brady |year=1984 |isbn=978-0835954105}}
Notes
{{reflist}}
External links
- [https://web.archive.org/web/20071110200007/http://homepage.mac.com/lucaswagner/raskin/ The History of Apple's Pascal "Syntax" Poster, 1979-80.]
- [http://www.pascal-central.com/pascal-syntax.html Pascal Syntax Poster] {{Webarchive|url=https://web.archive.org/web/20210226203202/http://www.pascal-central.com/pascal-syntax.html |date=2021-02-26 }}
{{Pascal programming language family}}
Category:Disk operating systems