ST Format

ST Format
source
Name	ST Format
Developer	Atari ST community
Released	1980s
Latest release version	N/A
Operating system	Atari TOS
Genre	disk image / file format
Website	N/A

ST Format is a disk image file representation associated with the Atari ST family of personal computers and the broader 1980s home computing scene. The format captured sector layouts and copy-protection details used on floppy media distributed for platforms such as the Atari ST, Amiga, BBC Micro, and IBM PC. It served preservationists, archivists, and emulator developers working with software from publishers like Ocean Software, Electronic Arts, and Microprose.

Overview

The format records raw data from 3.5-inch and 5.25-inch floppy disks used on systems including the Atari ST, Commodore Amiga, Acorn BBC Micro, Apple II, and IBM PC. It was employed by preservation groups such as the Software Preservation Society, The Internet Archive, and demoscene repositories to capture copy-protection schemes from firms like Ocean Software, Psygnosis, Electronic Arts (EA), and Microprose. Enthusiasts used tools developed by authors affiliated with projects like Stefan Pettersson, Jeri Ellsworth, and communities around magazines such as ST Format (magazine), Amiga Format, and Compute!.

History and Development

Development emerged in the late 1980s and early 1990s amid disk imaging efforts parallel to formats like IMG (disk image), ADF (Amiga Disk File), and IPF (Interchangeable Preservation Format). Contributors included members of AtariAge, EAB (English Amiga Board), and preservationists cooperating with institutions such as The British Library and the Computer History Museum. Work was influenced by technical analyses from engineers associated with Atari Corporation, researchers from University of Cambridge labs, and archival initiatives promoted by magazines like ST Format (magazine), Amstrad Action, and Retro Gamer.

Technical Specifications

The format preserves low-level sector information including track timing, flux transitions, and sector headers for media used by controllers like the WD1772 and MB8877A. It accommodates nonstandard geometries found on disks distributed by publishers such as Sierra On-Line, Lucasfilm Games, MicroProse, and Infogrames. Documentation and reverse-engineering efforts cited work from engineers linked to Atari Corporation, developers active on GitHub, and contributors associated with projects like libchg and FluxEngine.

File Structure and Encoding

Files store contiguous raw track dumps with metadata describing rotation speed, encoding method (e.g., MFM), and sector interleave for disk images akin to those used by Stefano Falco-style utilities and emulators like Hatari, Steem SSE, and WinSTon. Metadata fields reference publisher identifiers and copy-protection markers used by companies such as Psygnosis and Ocean Software. Encoding supports both standard MFM layouts and bespoke encodings deployed by protection schemes from groups like Copylock and Rob Northen Copylock.

Tools and Software Support

Support exists across emulators, imaging tools, and archival utilities: notable projects include Hatari, Steem SSE, WinSTon, FluxEngine, KryoFlux, and community utilities maintained on GitHub and discussed on forums like AtariAge and English Amiga Board. Preservation workflows often combine hardware solutions from vendors like KryoFlux and CatWeasel with software developed by contributors linked to libdisk projects and archival sites such as The Internet Archive and World of Spectrum.

Usage and Applications

Archivists and collectors use the format for long-term preservation, analysis of protection techniques created by teams at MicroProse, Ocean Software, Psygnosis, and for running legacy software on emulators such as Hatari and Steem SSE. Researchers at museums like the Computer History Museum and libraries including The British Library rely on such disk images when curating exhibitions related to companies like Atari Corporation, Commodore, and Acorn Computers. Demoscene historians studying groups like The Black Lotus and Fairlight use images to verify originality and authenticity.

Compatibility and Conversion

Conversion tools translate images to other archival formats including IPF (Interchangeable Preservation Format), ADF (Amiga Disk File), and raw sector dumps understood by emulators such as Hatari and WinSTon. Interoperability depends on preserving low-level flux information; hardware-assisted readers from KryoFlux or FluxEngine are frequently required. Community repositories on GitHub, discussions on AtariAge, and contributions from projects such as libdisk provide conversion scripts and documentation.

Category:Disk image formats Category:Atari ST