I have two USB floppy drives, the first an unbranded Chinese one just vaguely marked "FD-05PUB" (identified by Windows as a "Mitsumi USB FDD 061M" - top one on the picture) and the second a Proxima Direct unit. Both look similar in their bog-standard slimline plain black cases.
The first one won't handle DSDD floppy discs (probably doesn't have a disc type sensor or differences in the controller, I don't know), but the other will.
They are used on a Windows 7 and a Windows 10 PC and can be mixed on the same PC with QPC2 for copying files between floppy discs. As you would expect, they appear as drive A: and drive B: on the PC side, which is usually flp1_ and flp2_ in QPC2. Both work well from both QPC2 and QemuLator, although only the Proxima Direct will handle DSDD 720K discs.
When using DSHD 1.44MB floppy discs, both drives format normally from Windows, DOS command line and from the emulators.
When using DSDD 720K floppy discs, neither will format from Windows (e.g. right click on the floppy drive icon in File Explorer and click on FORMAT).
But if you go into a command prompt (the old DOS commands prompt), the Proxima Direct drive can be persuaded to format DSDD 720KB floppy discs with this command, which Rich Mellor suggested some time ago:
Code: Select all
FORMAT A: /T:80 /N:9
The equivalent command for HD discs from Command Prompt is FORMAT A: /T:80 /N:18
Note:spaces before both forward slashes.
If you try this with the other floppy drive, tyou get an error message "parameters not supported by drive".
Moving to QPC2, it seems able to format DD discs in both drives, but seems unable to write to it after that. Hopefully Marcel will correct me if I'm wrong, it may be that the fast disc format routine in QPC2 just writes the information to somewhere in the first track on the disc and leaves the rest alone. Probably similar to a "Quick Format" in Windows.
Results seem similar with Windows 7 and Windows 10.
Having formatted the disc and copied some files to it in QPC2, I took the discs to a QL and an Aurora to see what would work and what wouldn't. The Aurora has an HD 1.44MB drive, the QL has a 3.2MB ED drive and a 720K DD drive. Results were good with HD discs, in that everything but the 720K DD drive were able to read as you'd expect.
The DD 720K floppy disc from QPC2 was read OK in the HD and ED drives, but unreliable in the DD drive on the QL. Presumably because both USB drives were HD drives and formatting and using DD discs in HD drives then trying to read them on DD drives is never guaranteed even though theoretically compatible.
Having formatted the DD discs on the QL's DD drive, then writing files to them in QPC2, then taking them back to the QL DD drive, it was a little bit more reliable, presumably the DD drive formatted the disc at the right density and magnetic strength etc.
So, in conclusion, this experience shows that some HD floppy disc drives are not capable of fully handling DD discs, but some are. I'm afraid I don't know whether this drive just hasn't got a disc density sensor or some other difference in the controller.