Ignorign Floppy disk errors or Raw-Read Raw-Write

Ignorign Floppy disk errors or Raw-Read Raw-Write

Post by Kieran O' Sulliv » Sat, 14 Dec 2002 00:16:46

Ignorign Floppy disk errors or Raw-Read Raw-Write
I am looking for 1 of 2 things either
1.  A program/procedure/set of steps which will allow me to read a
disk bit by bit.
2. A way to tell linux to ignore any and all errors comming from the
floppy drive.

Note: dd won't do it!

I have read in the df man page that it is possible to stop a floppy
disk drive from reporting errors.  Basically I have a copy portected
disk with different sized sectors on it and I want to make an image of
it and back it up so that if the disk goes I'm not completely screwed.
I have tried
dd if=/fd0 of=image bs=1 conv=noerror
When this gets to the magical mistery sector it continues to read it
and after 15 minutes I gave up hoping it would get over the sector.
dd if=/fd0 of=image bs=512 conv=noerror
works (in so much as it gets all the data but they disk knows its been
coppied and won't work)


1. Raw disk access and the 'raw' program

Someone in this group recently pointed me to the 'raw' program and using
it to access disk drives in 'truly raw' mode. It works great. But then I
tried the program on other machines and I've had various problems.

It works on Red Hat 6.2 with 2.2.14-5.0smp kernel. However, on RH 6.1
(2.2.12-20smp) and RH6.2 with 2.2.16 kernel it does not work.

2.2.12 says:

% raw -qa
Cannot open master raw device '/dev/raw' (No such file or directory)

2.2.16 says:

% raw -qa
Cannot open master raw device '/dev/rawctl' (No such device)

I know the 2.2.16 system is kind of flakey (not installed by me). But the
2.2.12 system seems like it should work.

The only thing I've found in the kernel source is the file
drivers/char/raw.c. This file is in the 2.2.12 source, but not in the
2.2.16 source that I have. Do I need to do something to enable the raw
access? Did I just get lucky with my first system? Possibly, but every
other 2.2.14 machine I have looked on works fine. It doesn't look like it
is a loadable module or anything...


I proclaim you, FOUR!

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