It is now common, especially when working on Windows PCs or Macs, to work with
Atari software as files or "images" containing the data from an entire disk,
data cassette, or cartridge as duplicated from the native media for the Atari.
Here is a list of file formats, arranged by their associated filename
extensions. These are all filename extensions used to name files containing
entire 8-bit Atari floppy disk images, cassette tape images, or cartridge
.DCM -Image format invented by Bob Puff for his Disk Communicator 3.2 utility.
Used when working with native Atari hardware.
DISKCOMM is at http://www.nleaudio.com/css/files/DISKCOM.ARC
DCM specs at: http://home.planet.nl/~ernest/diskcomm.zip
.ATR -Image format invented by Nick Kennedy, for his SIO2PC project.
Used with most 8-bit Atari emulators running on other computer
platforms. SIO2PC is at http://www.cox-internet.com/wa5bdu/sio2pc.htm
.XFD -Image format invented by Emulators Inc, for their ST Xformer emulator.
Identical to ATR except without the 16 byte header.
Used with ST Xformer and PC Xformer emulators.
Xformer is at http://www.emulators.com/
.PRO -Image format invented by Steven Tucker, for his APE ProSystem device.
Used with APE, the Atari Peripheral Emulator.
APE and APE ProSystem are at http://www.atarimax.com/
.SCP -SpartaDOS SCOPY image file. SCOPY was a utility by ICD.
.DI -Image format invented by Kolja Koischwitz & Christian Kruger for their
800XL DJ emulator for the Atari ST.
.CAS -Cassette image format invented by Ernest R. Schreurs, for his
Digital Cassette Image system (includes CAS2SIO, WAV2CAS, and CAS2WAV
MS-DOS utilities. See: http://home.planet.nl/~ernest/
Atari Disk Image FAQ (Steve Tucker)