I have a few collections of Atari 8-bit images that I've downloaded over the years, but only cherry picked into them. I'm at the point that I'd like to clean things up a bit and get rid of files that I don't need (e.g. MS-DOS .COM files) and just focus on the disk, tape and cartridge images.

I've found a few random posts and FAQs on the internet, but none of them seem complete. I've found some that list .dcm, .atr and .xfd but then fail to recognize .md8 for example.

Does someone have a definitive list?

  • Are you primarily interested in file name extensions (which are, after all, somewhat arbitrary), or the data formats used for the purpose and what file name extensions those typically use/d?
    – user
    Jun 9, 2017 at 14:13
  • @MichaelKjörling I'm more interested in the file extensions so that I can search my collections and identify which ones are images and which ones are disposable. I know the internal data format could differ, but not as interested in that since the extensions typically identify what data format is inside.
    – bjb
    Jun 9, 2017 at 14:17
  • 1
    Please don't delete these files with a script. They may not have been popular programs and may not be available any more, so you might be deleting a piece of history.
    – wizzwizz4
    Jun 9, 2017 at 15:40
  • 1
    @wizzwizz4 These were from torrents so I'm guessing they're not unique to me! Regardless, I still have the .7z files they came from and can make them available if someone needs.
    – bjb
    Jun 9, 2017 at 16:47

1 Answer 1


In practical terms, what really matters is which Atari 8-bit binary image formats and extensions are recognized by the popular Atari 8-bit emulators. Emulators (especially open-source ones that can share code amongst multiple projects) form the de facto "specifications" for binary image formats because it is almost always the emulator that is (or becomes) the primary client application to consume those binary image formats.

Based on this practical association between the emulator support and what binary image formats and extensions are really viable, I offer this list, which comes directly from Altirra documentation

Support for most popular 8-bit image file formats: ATR, ATX, ATZ, DCM, XFD, PRO, ARC, BAS, ROM, BIN, A52, CAS, SAP

Additionally, Altirra documentation says the emulator supports Atari 8-bit executables with expected extensions of OBX and XEX.

  • 2
    Unfortunately that list is incomplete (Altirra supports other formats). Or perhaps more accurately, there are files which aren’t images but are useful with emulators (e.g. on 8-bit Ataris, XEX files). Jun 9, 2017 at 15:32

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