CP/M and UCSD p-System

CP/M and UCSD p-System

Already in the early days of UCSD p_system 8080, Z80 and 6502 were target architectures, next to PDP-11. The 6502 way led to Apple Pascal, and other systems like OSI.
The 8080 and Z80 way was of course targeted at the then popular CP/M machines, many did get a UCSD implementation, from I.4 to IV.

Documentation (also see the UCSD and Softech documentation!)

MC-1000 UCSD Pascal Installation Guide
NorthStar Pascal Revision 1 System Reference Manual
UCSD p-System for the Osborne 1
UCSD_p-System II.0 Installation for Altos ACS-8000-15 1982

UCSD Z80 CP/M adaptable system
UCSD Z80 CP/M sources, another large collection
Various disk iamges for UCSD p-System CP/M implementations

There are still CP/M systems for sale, completely open source, in kit and assembled form. The MBC-2 is a fine example.
UCSD Pascal is running on the Z80-MBC2, stored on a SD card. Version IV.0. I have bought an assembled kit, recommended!
A real Z80, real CP/M, mass storage via an SD card, so no floppies or old hard disk.

Users of MBC-2 can use the latest firmware and have UCSD IV running.
The interesting page of GmEsoft shows how the UCSD ssytem was adapted to the MBC-2.


There are many many Z80 CP/M emulators, all with varying quality and usability.

AltairZ80 by Peter Schorn

This emulator, based on SIMH, does a good job of emulating an Altair with UCSD II.0.

Homepage is here, look there for the latest and much more CP/M emulation goodies!

And here a local copy of the files required to get this running.

Instructions how to run Altairz80 with UCSD:

  • Download in a convenient directory and unpack the archive
  • On current Windows version to get ANSI support in command window console, start the registry editor
    – in HKCU\Console create a DWORD named VirtualTerminalLevel
    – set it to 0x1
  • Start a Command Window (Run CMD) in the altair directory
    altairz80 ucsd


The other one claimong to emulating UCSD Pascal I, II and IV is Z80pack. A lot of work to get it running, Linux seems well supported, on Windows it should work but I did not succeed in the limited couple of hours I thought were enough and many searches on the internet and gave up for now.