Re: How To Read Volume ID from DVD

[m <maglyx@gmail.com>]

> CDROM is the default volume id of mkisofs.
> -V volly should have overridden that.
>
> volname works for me.
> Own backup formatted by xorriso:
>   $ volname /dev/sr2
>   UPDATE_HOME_2008_12_09_115802

My apologies, my example indicated a first (-Z) session but should
have been of a subsequent (-M) session. The explanation for why
volname returned "CDROM" is that is apparently the default volume
label when none is specified (which wasn't in the first session). I
specified "volly" on a later session but volname and vol_id (which
someone else suggested) appear to not be multi-session aware and
return data only from the first session.

> One can get the volume id from xorriso too:
>   $ xorriso -indev /dev/sr2 2>&1 | grep '^Volume id'
>   Volume id    : 'volly'

Thanks, I hadn't heard of this tool and indeed it works, properly
returning info from the latest session. As well I see its -toc mode
emits the volume IDs for each session, vs.wodim -toc which doesn't
show this.

> Or make an attempt with vanilla tools:
>   $ dd bs=1 skip=32808 count=32 if=/dev/sr2 | strings
>   volly
> (ECMA-119 8.4.6 Volume Identifier (BP 41 to 72)
> under the assumption that the PVD is at LBA 16.)

I had begun reading ECMA-119 last night when it appeared there was no
way to do this but write my own code. My case is multi-session discs
so it'll take a little more than this. I've still got to look at
ECMA-168 to see how to find the start of each session.

I found there are various other fields (e.g. application identifier)
the image creation tools will allow you to specify yet even the
relatively heavy weight tools don't appear to expose, so I'm going to
write a simple tool a la volname but multi-session aware and that can
report the other volume descriptor fields.