Magneato

A command-line tool for parsing and extracting Extended CPC DSK (eDSK) disk image files. Magneato provides a clean interface to inspect, unpack and pack DSK files into a structured directory format.

Currently experimental

Features

• Parse DSK files: Read and validate Extended CPC DSK format files
• Inspect disk images: Display detailed information about tracks, sectors, and metadata
• Extract disk images: Unpack DSK files into a structured directory hierarchy with separate data and metadata files

Installation

Prerequisites

• Go 1.16 or later

Build from Source

git clone <repository-url>
cd Magneato
go build -o magneato

Or run directly:

go run src/. <command> <filename.dsk>

Usage

Magneato supports three commands:

Info Command

Display detailed information about a DSK file:

magneato info disk.dsk

This will show:

• Disk signature and creator information
• Number of tracks and sides
• Track-by-track breakdown with sector details
• Sector metadata including FDC status registers

Unpack Command

Extract a DSK file into a structured directory:

magneato unpack disk.dsk

You can also specify a --data-format that allows choices of binary, hex, quoted and asciihex. ASCIIHex is a compact human-readable format that shows ASCII where possible but toggles back and forth to HEX when needed. The final character in the string is the toggle character.

This creates a directory structure:

disk/
├── disk-image.meta          # Disk-level metadata (JSON)
├── track-00-side-0/
│   ├── track.meta           # Track metadata (JSON)
│   ├── sector-0.bin         # Binary sector data
│   ├── sector-0.meta        # Sector metadata (JSON)
│   ├── sector-1.bin
│   ├── sector-1.meta
│   └── ...
├── track-00-side-1/
│   └── ...
└── ...

Directory Structure

• Root directory: Named after the DSK file (without extension)
• Track directories: Named track-XX-side-Y for multi-sided disks, or track-XX for single-sided
• Sector files:
  • sector-N.meta: Sector metadata in JSON format
  • sector-N.bin: Sector data in raw binary format
  • sector-N.hex: Sector data in hex format
  • sector-N.quote: Sector data in quoted-printable format
• Metadata files:
  • disk-image.meta: Disk header information
  • track.meta: Track header information

Pack Command

The reverse of unpack this combines the various files back into a .DSK file attempting to preserve precision and minimize data and meta loss.

File Formats

Magneato supports both Standard and Extended CPC DSK formats:

Extended DSK Format (eDSK)

• Disk Header: 256-byte header with signature, creator info, and track size table
• Track Blocks: Variable-length blocks containing track headers and sector data
• Sector Information: 8-byte descriptors with cylinder, head, sector ID, and FDC status
• Sector Data: Raw sector payloads with variable lengths

Standard DSK Format

• Disk Header: 256-byte header with signature, creator info, and fixed track size
• Track Blocks: Fixed-size blocks (all tracks same size) containing track headers and sector data
• Sector Information: 8-byte descriptors (last 2 bytes unused) with cylinder, head, sector ID, and FDC status
• Sector Data: Raw sector payloads with fixed sizes per track

Note: Magneato can read both formats, but only Extended DSK format can be written (via the pack command).

Project Structure

.
├── main.go      # Command-line interface and entry point
├── types.go     # Type definitions and constants
├── parser.go    # DSK file parsing logic
├── dsk.go       # DSK methods (info, unpack, etc.)
└── README.md    # This file

License

This project is dual-licensed under:

• Apache License 2.0 - See LICENSE-APACHE file for details
• MIT License - See LICENSE-MIT file for details

You may choose either license at your option.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

AI Disclosure

This tool with developed using AI tooling from Google (Gemini 3 Pro) and Cursor (default model).