The .DSK Format

In general, disk images for the +3 Spectrum are thought of as being in DSK format. However, this is actually an slight oversimplification; there in in fact two similar, but not identical, DSK formats. (The difference can be seen by doing head -1 dskfile: one format will start ‘MV - CPCEMU’ and the other will start ‘EXTENDED’).

The Fuse +3 FDC emulation supports both the ‘CPCEMU’ format and the extended format, as well as other goodies such as compressed disk images.