UCSD Pascal was a specific implementation of the programming language Pascal which used the p-Code machine architecture. Pascal is one of the landmark computer programming languages on which generations of students cut their teeth and variants of which are still widely used today. ... In computer programming, a virtual machine executing p-code, the p-Code machine or pseudo-code machine was the target of early Pascal compilers. ...
Notable was the introduction of separately compilable Units and a String type. Both of which influenced the design of the Ada programming language. Ada is a structured, statically typed programming language designed by Jean Ichbiah of CII Honeywell Bull in the 1970s. ...
The UCSD Pascal compiler was distributed as part of a portable operating system, the p-System. In computing, an operating system (OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... The UCSD p-System or UCSD Pascal System was a portable highly machine independent operating system developed in 1978 by the Institute for Information Systems of the University of California, San Diego to provide all students with a common operating system that could run on any of the then available...
There were four versions of UCSD p-Code engine (p-Code incompatible) each with several revisions of the p-System (and UCSD Pascal); represented with the leading Roman Numeral; operating system revisions were enumerated as the "dot" number following the p-Code Roman Numeral. vis: II.3 represented the third revision of the p-System running on the second revision of the p-Machine.
Version I
Original version, never officially distributed outside of the University of California, San Diego. However the Pascal sources for both Versions I.3 and I.5 were freely exchanged between interested users. Specifically the patch revision I.5a was known to be one of the most stable.
Version II
Widely distributed, available on many early microcomputers.
Version III
Custom version written for Western Digital to run on their Pascal Micro-Engine microcomputer.
Version IV
Commercial version, developed and sold by Sof-tech. Did not sell well due to combination of their pricing structure, performance problems due to p-Code interpreter, and competition with native operating systems (which it often ran on top of). After Sof-tech dropped the product it was picked up by Pecan Systems (a relatively small company formed of p-System users and fans). Sales revived somewhat, due mostly to Pecan's reasonable pricing structure, but the p-System and UCSD Pascal gradually lost the market to native operating systems and compilers.
UCSDp-System (Version IV, supplied by SofTech) was one of three operating systems (along with PC-DOS and CP/M-86) that IBM offered for its original IBM PC; but the p-System never sold very well for the IBM PC, mainly because of a lack of applications and because it was more expensive than the other choices.
UCSDp-System began around 1977 as the idea of UCSD's Kenneth Bowles, who believed that the number of new computing platforms coming out at the time would make it difficult for new programming languages to gain acceptance.
UCSD introduced two features that were important improvements on the original Pascal: variable length strings, and "units" of independently compiled code (an idea taken from the then-evolving Ada programming language).
Feeds |
Contact