Hi, I am trying to understand the possible values for the MAX_FD variable used by the floppy controller model (hw/block/fdc.c).
Looking at git history: - 2004-01-05 7138fcfbf7dd + 8977f3c107ef (Jocelyn Mayer): FDC introduced with "#define MAX_FD 2" - 2008-04-29 78ae820cfeb0 (Hervé Poussineau): Supports up to 4 floppy drives if MAX_FD is set to 4 Migration stream knows about runtime value of MAX_FD - 2009-09-10 d7a6c2703577 (Juan Quintela): FDC vmstate-ified Migration stream use compile time value of MAX_FD Since 7138fcfbf7dd MAX_FD has always been defined as 2. Since d7a6c2703577 MAX_FD can not be different than 2 without breaking migration. If I understand correctly migration, first we should change in vmstate_fdc the user-definable MAX_FD by a constant 2 value. Then to be able to use >2 floppy disks I have to modify the the vmstate.version_id, and 1/ add a new field in the vmstate_fdc containing the number of drives and add code to check >2 and adapt or 2/ change MAX_FD to 4 for all the codebase, adding some code to migrate to older FDC with only 2 disks... Another option I don't like is: 3/ get ride of MAX_FD != 2 and clean the codebase... $ git grep '#if MAX_FD' hw/block/fdc.c:744:#if MAX_FD == 4 hw/block/fdc.c:758:#if MAX_FD == 4 hw/block/fdc.c:1317:#if MAX_FD == 4 hw/block/fdc.c:1340:#if MAX_FD == 4 hw/block/fdc.c:2041:#if MAX_FD == 4 hw/block/fdc.c:2079:#if MAX_FD == 4 hw/block/fdc.c:2104:#if MAX_FD == 4 Hervé, what board are/were you using with 4 floppy drives? BTW this link is somehow interesting :) https://www.seasip.info/VintagePC/floppies.html Thanks, Phil.
