UCSD Pascal: what changed
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Title: UCSD Pascal
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| 1 | + | **UCSD Pascal** was the first minicomputer and microcomputer implementation of the [[Pascal]] programming language. Developed at the University of California, San Diego, under the direction of Kenneth Bowes, it implemented a number of significant improvements to the [[Standard Pascal|standard Pascal]] language, including | |
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| 3 | + | - Separate compilation of programs by use of the [[Unit|unit]] directive. | |
| 4 | + | - Implementation of a means to distinguish between disk files and screen files, so that interactive applications could be developed. | |
| 5 | + | - On-screen compilation including an interactive editor such that indications of errors in the program detected by the [[Compiler|compiler]] could be transferred back to the editor to allow the exact line that the error occurred on to be highlighted, along with the precise error message. | |
| 6 | + | - Variable length strings, including [[Procedure|procedures]] to handle them. | |
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| 8 | + | UCSD Pascal was implemented on | |
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| 10 | + | - Terak computer system, which used the PDP-11 processor and a bit-mapped screen similar to the original Apple Macintosh computer. | |
| 11 | + | - The Apple II with the 80-character video card. | |
| 12 | + | - The IBM-PC. | |
| 13 | + | - The Texas Instruments TI 99/4A, which used the TMS 9900 processor. | |
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| 15 | + | UCSD Pascal compiled to [[P-Code]] that was executed by a virtual machine (similar to Java byte-code and the JVM). The compiler and virtual machine ran on the UCSD p-System [[Operating System|operating system]] which had its own file format for its disk directories, different from any other microcomputer operating system file format at the time, as it handled filenames longer than the then-standard 6 + 3, and later 8 + 3 formats, and also could handle filenames containing one or more blanks. | |
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| 17 | + | Most of the operating system was itself written in UCSD Pascal, apart from the machine-dependent parts. To make this possible, UCSD Pascal was also expanded with some features, mainly aimed at system programmers | |
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| 19 | + | - Handling of untyped data. | |
| 20 | + | - Access to untyped files, as well as the ability to read and write blocks directly on a disk. | |
| 21 | + | - Concurrent processes. | |
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| 23 | + | ## Source code | |
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| 25 | + | Version I.5 of UCSD Pascal is nowadays available under a non-commercial open source license. The [[Source code|source code]] of this version can be found on the [[FPC|Free Pascal]] ftp site at <ftp://ftp.freepascal.org/pub/fpc/attic/ucsd-pascal> | |
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| 27 | + | --- | |
| 28 | + | *From the Free Pascal wiki, page "UCSD Pascal", as it stood on 2019-08-23 after a change by Djzepi, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).* |