Re: Can Linux read DMF format floppies?

Derrik Pates (
Tue, 20 Aug 1996 11:42:31 -0600 (MDT)

On Tue, 20 Aug 1996, Jon Katz wrote:

> Good question... and I, as the guy who wrote the Linux+Win95 mini-HOWTO
> should know the answer, but I don't. The thing with DMF is that the ONLY
> thing you'd be able to read is the MS-Installation stuff (office, Win95,
> NT, etc, etc). DMF doesn't appreciate it when you try to delete things
> off the media. The installation files won't delete off of them... (I've been
> trying to re-use all the DMF disks that MS sent
> me when I was a beta tester. The total is around 100!) but the only way I
> can use those disks is to re-format them as 1.44M.

No, actually - DMF disks CAN have files deleted from them, but they used
some sort of trickery (did a ScanDisk on one once, and found a weird
hidden file on each one) to make it so files could be read, but not
written. See, shortly before I cleared my beta floppies (yes, I was a
beta tester too) I tried removing a CAB file from one and putting the
original file on my hard disk in the mean, then trying to copy the file
back. However, after the file had been removed from that floppy, it would
not go back on to it. It had something to do with those weird hidden files

> Try mounting a DMF disk on /dev/fd0 and see if it works. Win95/DOS has no
> special support for DMF (hence it can't delete or write to the disk, only
> read).

I tried it once, but Linux only reported 1440K, not 1680. I think if you
tried to mount the format-specific device, it would most likely work.

> There are actually a few different versions of DMF out there (two or
> three). This is because the folks at MS changed the format during the
> Win95 beta process.

Yes, but that doesn't matter, because I have a feeling most of those beta
disks went sour anyhow (most of mine did anyway) but who cares... they
won't be any good after the end of this year... :)

Derrik Pates