CrossDOS is a file system handler for accessing FAT formatted media on Amiga computers. It was bundled with AmigaOS 2.1 and later. Its function was to allow working with disks formatted for PCs and Atari STs (and others). In the 1990s it became a commonly used method of file exchange between Amiga systems and other platforms.
CrossDOS supported both double density (720 KB) and high density (1.44 MB) floppy disks on compatible disk drives. As with AmigaDOS disk handling, it allowed automatic disk-change detection for FAT formatted floppy disks. The file system was also used with hard disks and other media for which CrossDOS provided hard disk configuration software. However, the versions of CrossDOS bundled with AmigaOS did not support long filenames, an extension to FAT that was introduced with Microsoft's Windows 95. (Full article...)