Re: problem with dd for floppy under 2.4.0

Mikael Pettersson (mikpe@csd.uu.se)
Tue, 23 Jan 2001 13:08:54 +0100 (MET)


On Mon, 22 Jan 2001 23:23:36 -0600 (CST), Thomas Molina wrote:

>[1.] One line summary of the problem: seek= parameter for dd under 2.4.0
>gives permission denied error
>[2.] Full description of the problem/report:I was creating a new
>root+boot disk for 2.4.0 this evening. I issued the command:
>dd if=/tmp/rootfs.gz of=/dev/fd0 bs=1k seek=335
>
>and got the error message:
>dd: /dev/fd0: Permission denied

There's a known bug in dd where it incorrectly attempts to truncate
the output file even though it's a block device. In kernels older
than 2.4.0-test10 or so it got away with this, but now the kernel
correctly returns an error.

Use the 'conv=notrunc' option to dd to fix this, i.e.

dd if=rootfs.gz of=/dev/fd0 bs=1k conv=notrunc seek=XXX

/Mikael
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