andydvsn
commented
3 years ago From @Bobbi:
I think I remember reading in the MMFS2 docs from mm67 that writing is intentionally disabled if the name doesn't end in SSD or DSD. This is (I assume) to avoid scribbling over random files. Personally I wouldn't mind just disabling that.
The other alternative is to modify MMFS2 so that disk files must be called .SSD or .DSD but so it is not necessary to type the extension when doing DIN, so DIN 123 would look for 123.SSD (and if not found 123.DSD ... or the other way around.) That way we can have files with extensions and the games menu(s) will still work.
Reported by @Wheel_nut on the Stardot forum it would seem that when the file extension is omitted, the disk image is mounted as read-only.
The extension is dropped for brevity or to provide some degree of backwards compatibility with existing menu systems.