using dd to duplicate cf cards

I’m trying to duplicate compactflash drives using dd.

If I type:
dd if=/dev/hd1 of=flash.img

it does seem to work, but I get an error message right at the end of
‘resource temporarily unavailable’.

whereas if I was copying the mounted filesystem, I could type
dd if=/dev/hd1t77 of=flash.img

then I would no longer see the error message, but the resulting file is
slightly smaller and does not produce a viable flash drive when I write it.
I guess that makes sense; I’m seeing the disk as interpreted by the
filesystem, not as it really is…

I’m writing using dd if=flash.img of=/dev/hd1

so it makes sense to do the exact opposite. I was just wondering if anybody
could explain the odd error message; it doesn’t seem to stop the resultant
copy from working.

I’d actually like to be able to copy these flash images under windows; does
anybody know of a simple program that can image a compactflash device under
I know of Norton Ghost and Powerquest DriveImage, and apparently rawrite has
been ported (but I think it only does floppies). I was thinking of trying
dd under cygwin…

Michael Tomlinson