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  Z-80 Public Domain "Embedded systems specialists"
CP/M and our replacement operating system, QP/M, are well past their prime: the days of being the center of computer attention is long over!

Still, there are many people who still use these systems, usually as a hobbyist or curiousity: some still have operational hardware and many run one of the many Z-80 emulators on their PC.  There is one emulator available below.

If you have a Z-80 CP/M or QP/M system or you have installed a PC emulator, here are some Z-80 (CP/M) programs to help you get started.

Z-80 Public Domain Utilities

Included here is NULU, a public-domain LBR handler for QP/M and CP/M systems written by Martin Murray.  The LBR included here package includes a set of public domain programs that were offered by other developers into the public domain and provided free on the QP/M distribution disk.  There are a number of programs included in this library, many of which were found and added at the last minute.

The downloads for NULU and for all of the public domain programs listed above are available here:

Package Version Date Size (bytes) Download time
(28.8K baud)
Click to
NULU.COM for CP/M (and QP/M) 1.5 Nov 1985 14k 6sec nulu.com
Public domain utilities provided with QP/M n/a 1980s 55k 21sec z80util.lbr

Installation of an LBR package entails copying NULU.COM onto your CP/M or QP/M system (or using import with MYZ80) and then running NULU and extracting the files from the LBR package to your system.  Note: If you are having trouble downloading NULU, try downloading NULU.ZIP instead (and then extracting NULU.COM from there).

Z80 Emulator for the PC

In the webmaster's opinion, there is only one Z-80 emulator you should use on your PC: MYZ80. Written seemingly eons ago, Simeon Cran's emulator has stood the test of time:
  • supports all documented and undocumented Z-80 instructions
  • extremely fast highly optimized emulation
  • very slick interface to the IBM PC that allow anyone to add O/S extensions easily
  • precisely and correctly handles CP/M disks (via a single PC file per CP/M disk)
  • easy to substitute any operating system or BIOS

My goal was to have two MYZ80 downloads available here: Simeon Cran's MYZ80 in its original ZIP format and our expanded version that comes preconfigured with QP/M and some other Z-80 programs MICROCode Consulting wrote during that period.  Unfortunately, I have been unable to reach Simeon Cran to get permisiion, so instead I included:

  • Simeon Cran's original MYZ80 package, unaltered
  • QP/M package for MYZ80 that includes instructions (QPMNOTE.TXT), two different MYZ80 boot files for QP/M, and the QP/M Z-80 files in QPMFILES.LBR so you can easily configure MYZ80 for QP/M.  (You will also need to download NULU.COM to extract files from the library.)

In addition, a set of programs for manipulating .LBR files on the PC, which was handled by NULU.COM and was the "ZIP" of its time for the Z80, is also provided.  Enjoy!

Package Version Date Size (bytes) Download time
(28.8K baud)
Click to
Original MYZ80 package 1.11 Apr 1993 91k 34sec myz80111.zip
QP/M operating system package for MYZ80 2.71 Sep 2002 84k 30sec qpmpkg.zip
LBR (NULU-capable) utilities n/a Nov 1999 32k 12sec lbrutil.zip