Bootable Floppy from CD?

From: John Foust <jfoust_at_threedee.com>
Date: Fri May 26 08:20:28 2000

At 11:57 PM 5/25/00 +0000, Eric Smith wrote:
>John Foust <jfoust_at_threedee.com> wrote:
> > The 'dd' approach has a few failings. One, it's not tolerant of
> > bad sectors, right?
>
>No, but then not much PC software is. I normally only worry about
>making disk images of good disks; I don't have any use for preserving
>bad ones. Assuming that it made sense to save an image of a partially
>bad diskette, how would you represent bad sectors?

As my web page mentions, Sydex's Anadisk defined a file format that
wrapped the sectors, allowing you to mark one as bad. I wish there
was a popular and universal way of archiving floppy disk images
this way. Our hobby really needs it. The emulation scene must've
solved parts of this problem already.

If you have a disk with bad sectors and you try the 'dd' approach,
it just fails. Where's the fallback? I realize I'm picking nits
here. I'm sure 'dd' or rawread/rawrite would serve Chuck's purposes
for now, putting a significant dent in his pile of floppies, leaving
perhaps only one or two with unarchivable read errors.

I have a bunch of 8 inch disks from my Terak, RT-11, CP/M, etc.
machines with bad sectors. When I tried to archive my C-64 disks
I found plenty with bad areas. I gave up.

This might be a good time for one of the disk experts to tell
us about common failure modes for various disk drive and media
technology.

>For dos diskettes, it's just about as easy as tar or zip when either
>using mtools, or mounting the image file using the loopback device.

Yes, but a search through all your disk images would be a lot of
mounting and un-mounting. You'd need to write scripts or tools in
either case to aid a search.

>As I mentioned, Linux *has* /dev/fd0xx variations for all of the common
>PC disk formats.

Chuck said "unix" not 'Linux'. :-)

- John
Received on Fri May 26 2000 - 08:20:28 BST