Date: Sun, 21 Nov 1999 01:42:38 -0800 From: Mike Smith <mike@smith.net.au> To: Donn Miller <dmmiller@cvzoom.net> Cc: Alfred Perlstein <bright@wintelcom.net>, current@FreeBSD.ORG Subject: Re: dd and gzip'd files Message-ID: <199911210942.BAA00370@dingo.cdrom.com> In-Reply-To: Your message of "Sat, 20 Nov 1999 02:26:41 EST." <38364D31.F1AD476E@cvzoom.net>
next in thread | previous in thread | raw e-mail | index | archive | help
> > > 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. > It appears to have worked. I guess the output block size of 16k > is key for floppies, then. The conv=osync does the padding. No, the block size requirement for floppies is 512 bytes, as it is for almost any device. conv=osync is correct if you insist on using the raw device. Note that the optimal block size for 1.44MB floppies is 9k (one track). -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199911210942.BAA00370>