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Bug 97543 - dd with if=/dev/fd0 hangs system
dd with if=/dev/fd0 hangs system
Product: Red Hat Linux
Classification: Retired
Component: kernel (Show other bugs)
i686 Linux
medium Severity high
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Assigned To: Arjan van de Ven
Brian Brock
Depends On:
  Show dependency treegraph
Reported: 2003-06-17 11:41 EDT by jason
Modified: 2007-04-18 12:54 EDT (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2004-09-30 11:41:09 EDT
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Regression: ---
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RHEL 7.3 requirements from Atomic Host:
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Description jason 2003-06-17 11:41:40 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003

Description of problem:
Several actions result in the system freezing; all of them involve the floppy
drive.  Ive already replaced the drive, cable, and floppies im working with.

First, using dd with the floppy.  The command
dd if=/dev/fd0 of=./bootdisk.img bs=512
always freezes the machine.

Second, trying to make a FAT16 on a floppy.  The command
mkdosfs -r 16 /dev/fd0
always freezes the machine.

Third, letting linux probe a floppy for filesystem.  The command
mount /mnt/floppy
freezes the system.  However, the command
mount -t msdos /dev/fd0 /mnt/floppy
mounts the floppy just fine allowing normal use.  The relavent line in /etc/fstab is

/dev/fd0                /mnt/floppy             auto    noauto,owner,kudzu 0 0

which works fine on other linux systems.

I suspect this might be a kernel problem, but I have no way to check that.  If
it is a hardware issue, then it is very specialised.  If i mount a floppy
explicitely, then there are no problems.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
dd if=/dev/fd0 of=./blah.img bs=512
mkdosfs -r 16 /dev/fd0
mount /mnt/floppy

Actual Results:  Total system freeze.  Had to hit the reset switch.

Expected Results:  copy the disk image
make a FAT16 filesystem on the floppy
mount a FAT12 filesystem

Additional info:

4 IDE channels with 4 drives might have a bearing(i doubt it though).
Comment 1 Alan Cox 2003-06-22 13:47:27 EDT
What chipset system ?
Is it multiprocessor ?
Does floppy=nodma as a boot option help ?
Comment 2 jason 2003-06-23 11:15:34 EDT
Motherboard is an asus P4S8X-X, single CPU, northbridge chipset is SiS 648,
southbridge is SiS 963.
floppy=nodma does seem to fix it.
Comment 3 Bugzilla owner 2004-09-30 11:41:09 EDT
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem

The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases, 
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/

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