Table of Content

Presentation

This page presents several Atari Floppy Disks image's formats. These images can be used for emulation or for preservation backup / copy of original Atari floppy disks. Some of these formats can be used directly (for example Pasti STX) in hardware / software emulators while some other may require to be converted (for example Kryoflux Stream files) by program like Aufit.

This page is related to the Atari FD Preservation page as well as the Atari FD Protection page.

 

Disk Image formats presentation

Disk images are mainly used by SW or HW emulators. There are a lot of sites dedicated to the subject of Atari emulation and I will therefore point you to a list of links on the subject.

The most widely used Atari software emulators are Hatari, Steem SSE, and Saint. The HxC2001 Universal FD Drive Emulator can be used to read FD images on real Atari.

The major disk image formats used by the Atari emulators are:

Note also that most recent emulators like Steem SSE can directly read zipped disk images. For example Steem SSE or Hatari can mount directly a zipped file (.zip) that contains a disk image of any of the supported disk image format.

Recently Steem SSE and

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Formats supported by emulators

The following table summurize the supported formats for each emulators:

 

  ST MSA DIM STT STX IPF CTR RAW SCP
Hatari Yes Yes Yes No Yes Yes Yes Conv Conv
Steem Yes Yes Yes Yes Yes Yes Yes Conv Yes
Saint Yes Yes Yes No Yes No No Conv Conv
USB HxC Yes Yes Yes Yes Yes Yes Yes Yes Yes
SD HxC Yes Yes Yes Yes No VBR No VBR Yes Yes Yes

 

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Making Disk Images from ST Original Floppies

This section try to answer the question: I have Atari floppies that I want to use with my favorite emulator...

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Making ST Floppies from Disk Image files

This section try to answer the question: I have some interesting disk images and I would like to create a FD to run on my real Atari...

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Other PC Disk image utilities

As already mentioned above, if you deal with disk images there is one program you must have: the Floppy Imaging & File transfer program (FloImg) from P. Putnik. This program can be used to create images in ST / MSA / STT format directly from a ST floppy placed in the PC Floppy Drive. It is also possible to create FD directly from images. It also support ST <-> to MSA conversion.

Another must have program is the MSA converter that run under Windows. This program not only allow conversion between different image formats but it also gives useful information about the image content.

My Aufit program can be used to convert Kryoflux RAW, or Supercard Pro SCP images to STX, ST, or MSA format.
For information there are some historical programs that run under DOS for st to msa conversion or from msa to st conversion. As well as two DOS programs to convert a PC disk to/from an ST disk.

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Documentation of Atari FD image formats

ST / MSA / DIM / STT Formats

All these formats are relatively simple and are described in my document

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STX Format

The Pasti format is the most widely used format for emulation as it provides a good support of protected disk. Almost any floppy disks can be imaged using this format and it is supported by STeem, and Hatari emulators. It is also supported by the HxC2001 HW Floppy Emulator.

Unfortunately Ijor, the creator, has not published information about the STX format. However several people have reversed engineered and described this format. You can find information in Markus Fritze page, in P.Putnik page, and information from the HxC2001 software (pasti loader).

I have written a complete documentation about the Pasti file format. This documentation is based on the above information as well as email discussion with Ijor. I have also written a small program to read and write Pasti file. The reader display detail information about the data and metatdata inside a Pasti file. Along with the documentation it can help to understand the Pasti file format. The Pasti Reader/Writer is part of the public domain Air project (Atari Image fileReader-Writer).

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IPF Format

The IPF (Interchangeable Preservation Format) is a file format created by SPS (Software Preservation Society). It is used to preserve the content of old floppy disks for many platforms. IPF files are created by SPS people by analyzing stream files created with the Kryoflux Hardware. The IPF file format reader project has been made public under MAME license. This was done by releasing the source code of a library called the IPF/CAPS library. Unfortunately the actual content of the IPF file has not been documented by SPS people and the only way to understand it was to interpret the released source code that allow to read an IPF file. This is not felt as a problem by most user as the content of IPF files is supposed to be read through the IPF decoder library and written only by SPS people. But for those that want to better understand the format I have created a documentation of the IPF file format. This can be useful just for the sake of understanding the format as well as for people that want to read or write IPF file directly.

The following document provides a description of the IPF Files content (as read by IPF Library v5.1) produced by the SPS people using the CTA Analyzer program. The document also provides assistance on Decoding or Encoding IPF Files. It is based on my understanding of the IPF documentations published by Software Preservation Society but it also includes information based on experimentations and programing. I want to thanks István Fabián and Keir Fraser from SPS who have provided to me with a lot of detailed information about the IPF file (see All you always wanted to know about IPF in the Kryoflux forum).

I have also written a small program to read and write IPF file. The reader display detail information about the data and metatdata inside an IPF file. Along with the documentation it can help to understand the IPF file format. The IPF Reader/Writer is part of the public domain Air project (Atari Image fileReader-Writer).

However beware that the information presented in the IPF documents comes from different sources and inevitably must contain errors and therefore must be used with caution. If you only need to read IPF files you should use the IPF library that will be be updated if the format of the file is changed.

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SCP Format

The SCP format is the format used by Supercard Pro device. The description of the format is available HERE and HERE

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RAW

The following document provides a description of the Stream Files content (as produced by firmware 2.0) produced by the DTC (Disk Tool Console) program connected to a KryoFlux Device. The document also provides assistance on Decoding or Encoding Stream Files. It is based on my understanding of the KryoFlux documentations published by Software Preservation Society and KryoFlux Product & Services Limited but it also includes information based on experimentations and programing (using sources provided by SPS). I want to thanks István Fabián from SPS who has provided to me with a lot of detailed information on how KryoFlux device operates and on the source code used to decode a Stream File.

Note: Regular user of the KryoFlux device should not be concerned by the information presented in this document which is mainly of interest to programmers that want to write tools around the Stream Files.

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References

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