Re: Can Linux read DMF format floppies?

Linus Torvalds (
Tue, 20 Aug 1996 09:37:27 +0300 (EET DST)

On Tue, 20 Aug 1996, Ron Holt wrote:
> Can Linux read DMF format floppies? DMF is Microsoft's "Distribution Media
> Format". Some of the applications they make are distributed in this floppy
> format. I don't know the exact geometry of these floppies. I've been
> told it's something like 21 instead of 18 sectors per track. Does anyone
> know where I can find a spec for DMF?

Linux should be able to read them: there may even be a pre-set format for

/dev/fd0H1680 (major 2, minor 44) should be a 21x2x80 3.5" floppy.

/dev/fd0H1722 (major 2, minor 60) should be a 21x2x82 3.5" floppy.

/dev/fd0H1743 (major 2, minor 76) should be a 21x2x83 3.5" floppy.

As to whether they actually work, I don't know. You can also create your own
geometries with the set_geometry ioctl - I think there is a "superfloppy"
package somewhere (Alain?) that contains the stuff to do all this.

> PS. Yes, I've looked at floppy.c in the kernel source...

My condoleances. It's horrible. A rats nest of code that is totally
incomprehensible. The only thing that excuses some of the code is the fact
that the hardware itself is such a rats nest. Ugh.

Oh, btw: check out "". It looks like
DMF is the 21x2x80 format (the first one on my list).