Subject: Re: Floppy driver
To: None <>
From: Brad Pepers <>
List: amiga-dev
Date: 02/28/1994 18:09:31
> 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.

I'm not sure what everyone is talking about with all this stuff. The
way I have it set up, the floppy driver just passes the whole disk of
sectors on to higher level programs that use them. Its up to the top
levels (filesystem, tar, ...) to use them correctly. The adosfs looks
at sector 0 to make sure its a valid amigados boot disk. Tar and ufs
just want direct access to the whole disk so they get it. No special
handling needed - just 1760 512 byte sectors to do with what you will!

Whats with the questions on skipping boot sectors and hiding sectors
and providing labels? I don't see these things as driver level stuff.
I'm sorry if I'm being daft here but I just don't understand.

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

+----------------------------Ren & Stimpy--------------------------------+
| "Psst. Hey Guido. It's all so clear to me now. I'm the keeper of the   |
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| why he's gonna kill us. So we gotta beat it. Yeah. Before he lets      |
| loose the marmosets on us! Don't worry, little missy! I'll save you!"  |
+------------------ Brad Pepers -- -------------------+