Very popular for educational purposes ...
:... if you do not like native coding compiler !
Nikolaus Wirth does not only invented a new programming language named 'PASCAL' (in fact it was influenced by Algol). He was also one of the heads of the "ETH Zuerich" until 1999. At the same place three men (Urs Ammann, Kesav Nori and Christian Jacobi) created also a "P4 compiler", which created P-Code, an artificial machine code (similar to the byte code from Java nowadays).
A short time later, at the University of California, San Diego, "UCSD Pascal" was created.
To get a deeper knowledge of details of the history, please visit the "UCSD P-system museum" here.
Here are some links to get in touch with the "real" stuff:
USCD Pascal for CP/M (at bitsavers.org, IMD disk images)
USCD Pascal II.9 for Altair Simulator/SIMH at Peter Schorn's site
Udo Munk's very interesting z80pack with a running UCSD I.5 system...
...and also the manual USCD Pascal Manual in PDF
UCSD Pascal I.5 Sources
UCSD files at bitsavers.org
A Yahoo group (registration unfortunately required) with infos and links
Reconstructed (not scanned) UCSD Pascal II.0 docs
More UCSD docs and a p-System running on DOS - see here
Mount an UCSD p-System disk images on Linux, look here
And a p-code L1-ADA compiler can be found at my ADA page.
A sample session with the DOS based P-System (download it at pascal.retro8bits.com from here) can be viewed here, it explains how to mount additional p-System volumes (with the help of a DOSFILER program) , how to list directories, mounted volumes and how to change the prefix.
Last but not least, here are the content of my rediscovered "Terak" archive file:
dir.lst (what I could read with the utilities from here)
I sent the archive file to Udo Munk may be he is able to do something more intelligent then I can do ;-)