The Amstrad CPC use 3" disks because Alan Michael Sugar got a large batch of 3" drives, and then stayed with it for compatibility. Game editors started to add protections to avoid piracy. Amstrad CPC emulators are using the .DSK format to store the content of a disk (but it assumes that each track have only one size). This format can't manage well protections, for this you need the extended DSK format where each track can have a different size to support more protections, but still not all of them. That's why hardware solutions are necessary to preserve the exact content of the original disks in their totality (and then you can write them again to real disks) such as :
- Kryoflux, this is the official hardware developed by The Software Preservation Society. More on Kryoflux features here. The kryoflux creates a file for each track of a disk in raw format (the track is read 5 times so about 250 Ko per track). Then there is the CT Raw, one file created from the raw tracks, and lastly the .IPF resulting from the CT Raw.
- SuperCard Pro (SCP), contrary to the kryoflux, the SCP creates one file for one disk. With a firmware update, the SCP will be able soon to become a floppy disk emulator like the HxC Floppy Emulator by Jean-François DEL NERO
There is a problem to create .IPF for Amstrad CPC programs, the real disks have been either :
- written in an usine so they will be seens as originals and IPF will be created
- written on a real Amstrad CPC, so they will be seens as copies and IPF wont be created
Every emulator can use the raw or CT Raw kryoflux files if using the SPS decoder library. If an emulator doesnt use this library, then the best thing is to use .DSK created from kryoflux files with Samdisk like those dumped by Maxit on CPC-Power. SuperCard Pro support must be added internally into an emulator. Sugarbox already supports the SCP and of course the kryoflux (from a kryoflux raw or CT Raw, sugarbox can create a SCP file). Samdisk will soon support the SCP hardware, so it will be possible to read one track only.