Date: Sun, 21 Nov 1999 09:57:57 -0800 (PST) From: "Rodney W. Grimes" <freebsd@gndrsh.dnsmgr.net> To: mike@smith.net.au (Mike Smith) Cc: dmmiller@cvzoom.net (Donn Miller), bright@wintelcom.net (Alfred Perlstein), current@FreeBSD.ORG Subject: Re: dd and gzip'd files Message-ID: <199911211757.JAA35922@gndrsh.dnsmgr.net> In-Reply-To: <199911210942.BAA00370@dingo.cdrom.com> from Mike Smith at "Nov 21, 1999 01:42:38 am"
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> > > > I recently tried using dd to transfer a binary image to floppy.
> > > > It was the Linux root disk image, color.gz. Basically, dd works
> > > > ok with non-gzipped files, but with files in gzip format, it
> > > > chokes:
> > > >
> > > > root@lc186 floppies# dd if=color.gz of=/dev/rfd0
> > > > dd: /dev/rfd0: Invalid argument
> > > > 2453+1 records in
> > > > 2453+0 records out
> > > > 1255936 bytes transferred in 42.665771 secs (29437 bytes/sec)
> > > >
> > > > Notice the line that says:
> > > >
> > > > 2453+1 records in
> > > > ^^^^^^
> > > >
> > > > For some reason, it is offsetting to 1 before writing to disk.
>
> No, that's not what it means. You are ignoring the error message on
> the preceeding line. "2453+1" means that it has read 2453 complete
> records and one extra byte. The 'fd' driver has (correctly) refused to
> write the single trailing byte.
Small technical correction, the value after the + is not bytes, but
number of partial blocks:
When finished, dd displays the number of complete and partial input and
output blocks, truncated input records and odd-length byte-swapping
blocks to the standard error output. A partial input block is one where
less than the input block size was read. A partial output block is one
where less than the output block size was written.
--
Rod Grimes - KD7CAX @ CN85sl - (RWG25) rgrimes@gndrsh.dnsmgr.net
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