Reading old disks on Linux - test-drb@ccmp.vtda.org

16 Oct 2002

Hi Patrick
 I think you might try looking at:

 http://www.moria.de/~michael/cpmtools/

This stuff is specific to doing cpm stuff but the
basics are there. One should be able to modify this
quickly to deal with any format that the hardware supports.
I've not looked at it closely but suspect it has what you need.
Dwight

...
 From: "Patrick Finnegan"
&lt;pat(a)purdueriots.com&gt;

On Wed, 16 Oct 2002, Fred Cisin (XenoSoft) wrote:

  Thanks
 It has some good information, some errors, and some good and bad guesses
 (such as saying that it is probably possible to read hard sectored disks
 with PC hardware) 
If you're refering to 'fixed format devices', they seem to be referring to
OS device nodes - such as "/dev/fd0h360", not physical (hard-sectored)
devices/disks.

  Are you trying to transfer files, or just read
raw sectors? 
For now, I just want to be able to copy disks without having to resort to
using teledisk on a machine running DOS.

  Which "odd formats" are you trying to
read? 
I was making a generalization... I've been able to successfully read
RX-50's created with teledisk using this method:

root@dualie:~# setfdprm /dev/fd1 qd sect=10 cyl=80 head=1
root@dualie:~# dd if=/dev/fd1 of=myfd.img
800+0 records in
800+0 records out
root@dualie:~#

I've also been successful with an Osborne Executive disk written with
teledisk:

root@dualie:~# setfdprm /dev/fd1 dd sect=5 cyl=40 head=1 ssize=1024
root@dualie:~# dd if=/dev/fd1 of=myfd.img bs=1k
200+0 records in
200+0 records out
root@dualie:~#

To me, it looks like the hardest part will be attempting to determine what
format the disk is in, automatically.  Any ideas?  My best guess is to do
a guess-and-check method, of course this would be tough to verify every
possibility, such as varied sector sizes (although it would be possible).
I'm guessing that I'll have to use a raw floppy ioctl to make that work.

One last thing, I found a reference to a program that could decode
teledisk 'normal' compression images in past postings to classiccmp, but
it's gone away and I didn't grab a copy before it did.  Anyone know where
I could find it?  Here's the original URL:

http://www.conknet.com/~w_kranz/WTELEDSK.HTM

Pat

  --
 Fred Cisin                      cisin(a)xenosoft.com
 XenoSoft                        http://www.xenosoft.com

 On Wed, 16 Oct 2002, Patrick Finnegan wrote:

 > Quite a while ago (and maybe more than once) we had a thread on
 > reading/writing 'odd' disk formats.  I thought about it again, typed a few
 > words into google, and found this:
 >
 > http://fdutils.linux.lu/Fdutils.html#SEC22
 >
 > It looks like setfdprm and superformat will do much of what's necessary in
 > working with 'odd' format disks.  I haven't played much with it yet,
but
 > I've verified it works for setting the density, heads, cyls, and
 > sect/track of the disk to write to.  However, it doesn't allow for
 > setting an initial sector number - something that's necessary for some
 > formats.  Using the program "fdrawcmd" should overcome any obsticles, but
 > will require more work to be useful.
 >
 > I just thought I'd pass this along in case people would find it useful. 
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