CP/M Neo

CP/M Neo is a lightweight operating system inspired by CP/M, designed for exploring the fundamentals of operating systems in a modern context. It provides a simple, portable development environment that emphasizes clarity, minimalism, and a return to core computing principles.

Key Features

• Portable Architecture: Designed to run across multiple processor architectures, with RISC-V provided as the default platform.
• CP/M-Inspired Environment: A familiar command-line interface and workflow inspired by CP/M 2.2.
• Sysgen Tool: The sysgen utility builds the operating system, creates disk images, and manages bundled applications.

Quick Start

CP/M Neo requires a C toolchain, make, and a POSIX-compatible shell. The default RISC-V toolchain is riscv64-unknown-elf-gcc.

Build the system with:

make -C sysgen
./sysgen/build/sysgen new --disk-size=2048K --platform=vemu

Build artifacts are placed in sysgen/build/, including:

• disk.img — the generated disk image
• bootloader.bin — the bootloader image
• Bundled applications — ready to run on the system

To clean the build:

make -C sysgen clean

Console Command Processor

CP/M Neo includes a Console Command Processor (CCP) that provides a familiar command-line environment for working with files, switching between volumes, and launching programs. Its command syntax is inspired by CP/M 2.2 while extending the environment for CP/M Neo.

Architecture

CP/M Neo is designed to keep applications largely independent of the underlying hardware. Applications run within the Transient Program Area (TPA) and interact with the operating system through its system-call interface, providing a consistent programming environment across supported platforms.

Documentation

The project includes documentation for both users and developers:

• User Guide — Build and run CP/M Neo.
• Architecture — Explore the memory layout and boot flow.
• CCP Reference — Reference for the Console Command Processor.
• Disk Format — Learn about the CP/M Neo disk-image format.
• Syscall Reference — Complete syscall API and ABI reference.
• Bundled Apps — Explore the applications included with CP/M Neo.
• Developer Guide — Learn how to use the SDK and develop applications.

CP/M Neo is a hands-on environment for learning how operating systems work, experimenting with low-level software, and rediscovering the simplicity of early personal computing.