Running Zork 1 on CP/M Emulator (z80pack) on Linux

Introduction to CP/M Emulation

This article details the process of running Zork 1, a classic text adventure game, within a CP/M environment emulated on Linux using z80pack. The choice of Zork 1 serves as a non-trivial example of a text-based program, avoiding the complexities of terminal-related issues that might arise with other applications like WordStar.

The primary motivation for this exercise is not practical gameplay, as Zork 1 is available through more modern means. Instead, the tutorial aims to provide familiarity with CP/M for those interested in retro computing, particularly for building Z80-based systems.

Understanding CP/M and Zork

Zork is an early example of interactive fiction, known as a 'text adventure,' which accepts simple commands like 'take axe' or 'look at box' to solve puzzles. CP/M is an early operating system originally designed for 8080 microprocessors but gained wider use with the Z80. It was foundational for early microcomputers and influenced later operating systems like MS-DOS.

Setting Up z80pack on Linux

To run CP/M on Linux, using a Z80 emulator like z80pack is a straightforward approach. The article outlines how to obtain and build z80pack and its associated CP/M tools for a Linux system. This involves downloading the source code, unpacking it, and compiling the core emulator and supporting tools using provided Makefiles.

The tutorial assumes familiarity with Linux command-line tools and a basic understanding of CP/M concepts. After compilation, a basic functional test involves starting CP/M 3 within the emulated environment.

Installation Steps for z80pack

z80pack is typically not available in standard Linux repositories, requiring users to download and build it from source. The process involves unpacking the source code into a chosen directory (e.g., $HOME/lib/z80pack-1.37).

Compilation is done by navigating to the respective source directories for the core emulator (cpmsim/srcsim) and supporting tools (cpmsim/srctools) and executing 'make -f Makefile.linux' in each. A basic test of the installation involves running './cpm3' from the cpmsim directory.