Subject: Re: Floppy driver
To: None <>
From: Ty Sarna <>
List: amiga-dev
Date: 02/28/1994 22:32:46
In article <> (Mike Schwartz) writes:
> I have a bit of advise here.  When I wrote MS-DOS or AmigaOS formatted
> floppies with my own drivers, I wrote two sectors on track 40 of the floppy
> to fool amigaos into thinking that the disk was indeed an AmigaOS disk but
> that it was 100% full.  My reasoning was that when someone sticks a disk in
> the drive and sees a bad volume reported by amigaos, they'd consider
> formatting it to use it :-)  With the 100% full (fill BAM sector with
> 0xffff), they saw the disk was valid and could not use DOS or some other
> program to write on the disk.
> 0xffff.  My floppy disk drivers would automatically skip writing or reading
> data from these two "magic" sectors.

Um, all of this and the disk IDs you mentioned before is great for your own
stuff, but we need a floppy driver that can interoperate with the rest
of the world, ie read and write normal MS-DOS, AmigaDOS, and tar disks.

> You also have to deal with track 0, where the boot sector goes.  Otherwise
> ADOS will not see it is a valid dos disk.

Probably the best way to do this is to have the disklabel faker routine
report two partitions, a which skips track 0, and c which covers the
whole disk.  You'd use 'a' in conjunction with adosfs, and 'c' with tar,
msdosfs, ufs, and everything else.

Ty Sarna                 "As you know, Joel, children have always looked        up to cowboys as role models. And vice versa."