Amiga Disk File aka ADF is a file format used by
Amiga computers and
emulators to store images of
disks. It has been around almost as long as the Amiga itself, although it was not initially called by any particular name. Before it was known as ADF, it was used in commercial game production, backup and disk virtualization. Technically speaking, ADF is not really a
file format but actually a track-by-track dump of the disk data as read by the Amiga operating system, and so the "format" is really fixed-width
AmigaDOS data tracks appended one after another and held in a file.
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