On Fri, 7 Mar 2003 00:47, bob parker wrote:
On Thu, 6 Mar 2003 06:03, Craig Dickson wrote:
bob parker wrote:
On Thu, 6 Mar 2003 04:22, Ray wrote:
how do i verify that the burned cd is correctly burned?
i burned a set of Debian 3.0r1 cds and have md5sums of the isos, but
they don't match the output of
md5sum -b /dev/cdrom
Not really an expert on what happens on cds but I belive it has
something to do with the some extra nulls packing it out to the end of
a 2048 block or something like that.
In any case the actual cd generally has a different md5sum than the
iso.
One way:
cat /dev/cdrom > test.iso
md5sum test.iso
md5sum original.iso
Isn't
md5sum /dev/cdrom
equivalent to
cat /dev/cdrom >test.iso
md5sum test.iso
If it is you will get the same md5sum from both, did you try it?
I've been using the file by file method in backup scripts without any
problems except when I get the odd coaster. So that may be the way to go.
Just to follow up my own post.
I'm using a new batch of cdrs and on 2 different burners
cat /dev/device > test.iso
fails, as does
md5sum /dev/device
but
dd if=/dev/device of=test.iso
succeeds.
If I recreate the iso using mkisofs after mounting the cdrom, the 2 iso's
give different md5sums.
If I mount the isos on the loop device and do a file by file md5sum, the 2
sets of sums are the same.
So it looks like the only way to verify your cd is on a file by file basis.
It also looks a bit like I have a sus batch of cdrs because I've made 2
coasters in 2 weeks, none at all from the batch before that.
Bob