26 May
2000
26 May
'00
1:20 a.m.
At 11:57 PM 5/25/00 +0000, Eric Smith wrote:
John Foust <jfoust(a)threedee.com> wrote:
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.
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? 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