odd dd issue?

[David E. Weekly]

Sorry to bug you guys, but I have an odd problem with dd. I'm putting
together a boot floppy with GNU/Linux. I already made an ext2fs file system
on /dev/fd0 and am now trying to write in my compressed file system to come
right after the boot portion: I'm doing this with "dd if=fs.img.gz
of=/dev/fd0 seek=335 bs=1k". dd tells me "/dev/fd0: Invalid argument"
despite the fact that there *is* a floppy in the drive that's known to be
writeable and without errors. An "of=/dev/fd91831903812" (completely bogus)
completes without complaint.

=/ Am I doing something horrendously stupid? This is with Mandrake's
fileutils-4.0-13mdk package. I was unable to find documentation on the Net
describing the source of this problem or its fix.

Oddly enough, an strace showed the problem occurring at ftruncate64() after
a successful open on /dev/fd0 -- and ftruncate64() was shown to be passed
five arguments, despite the fact that the documentation that I have in hand
(i.e., /usr/include/unistd.h & the kernel source) clearly shows ftruncate as
taking two parameters.

Apologies for disturbing you, but I wasn't able to find a better source of
documentation.

Yours,
 -david