Subject: Re: backup: dump | gzip | cdrecord ?
To: None <>
From: Dieter <>
List: netbsd-users
Date: 08/26/2005 09:30:23
> c) at least at first usage verify should be done after backup
> dd if=/dev/rcd0a bs=1m of=/dev/null progress=1

I'd suggest doing a real verify:

	dd if=/dev/rcd0a bs=1m of=some_tmp_file
	cmp original.iso some_tmp_file
	rm some_tmp_file

I had one disk that had 16 bytes miscompare (out
of an almost full 4.7 GB DVD)  IIRC it didn't have
any read errors, so just dd-ing it to /dev/null
wouldn't have caught the problem.

So far I've only had the one miscompare, using
DVD+rw and CD-rw media.

One additional suggestion: those who use write-once
media and have troubles with "burning coasters"
might want to consider rewritable media.
And checking the list of media that is recommended
for your make & model drive.