Code: [Select]
mame cpc6128 -exp hd20 -hard1 disk.chd
Only MAME CHDs are supported, you can create a blank hard disk image using chdman. Geometry is 615/4/17.
Code: [Select]
chdman createhd -o disk.chd -c none -chs 615,4,17
(-c none means no compression, but this is required for MAME to write directly to the CHD image. If you use compression, then data writes will be written to a separate file)