A gentle introduction to CP/M

Summary

[New to Gemini? Have a look at my Gemini FAQ.] This article was bi-posted to Gemini and the Web; Gemini version is here: gemini://gemini.circumlunar.space/users/kraileth/neunix/2025/gentle_introduction_cpm.gmi This article is just what the headline promises: an introduction to the CP/M operating system. No previous knowledge of 1970s and early ’80s operating systems is required. However, some familiarity with Linux or a BSD-style operating system is assumed, as the setup process suggested here involves using a package manager and command-line tools. But why explore CP/M in the 2020s? There are (at least) two good reasons: 1) historical education 2) gaining a better understanding of how computers actually work. Last year I wrote two articles about CP/M after having taken a first look at it: A journey into the 8-Bit microcomputing past: Exploring the CP/M operating system – part 1 A journey into the 8-Bit microcomputing past: Exploring the CP/M operating system – part 2 These were written with a focus on the first reason; I had (partially) read the manuals and tried out a few commands in an emulator (as well as done a little bit of research). I wrote an outsider’s look at CP/M and covered the various versions that were released and some of their notable features. This article is different. It’s for readers who want to get started with CP/M themselves. Expect a practical introduction to get familiar enough with the platform to be able to explore a wealth of historic software, often enough ground-breaking and influential. Getting Ready (Installing an Emulator) Last time I had tried out a couple of Z80 emulators and found Udo Munk’s z80pack to be the one I liked best. It’s not widely packaged; only FreeBSD includes it, but using the package requires some setup. Other options like YAZE exist, but it’s more work to get the original CP/M working on them whereas z80pack comes with disk images of various CP/M versions. Of course you can compile the emulator and tools yourself...