Re: DVD-R as backup medium: growisofs + udftools

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

> packet writing / udftools

I am not aware we have much expertise about this.

> dvd+rw-format -force /dev/sr0

This is for rewriteable DVD media only.
Not for DVD-R.
I guess dvd+rw-format would refuse anyway.


> DVD-RW: growisofs -Z /dev/sr0=/dev/zero
> But this does not sound good to me. Wouldn't this just waste my media?

Indeed. The procedure you describe would make
DVD-RW random access writeable with 32 kB
granularity and DVD+RW with 2 kB granularity.

The growisofs run would fill up any write-once
media and render it useless.


I am not sure whether udftools is suitable
for write-once media at all. Afaik, UDF has 
variants for re-writeable and for write-once
situations.


Let me propose to write ISO 9660 multi-session
instead.

You need mkisofs or its fork genisoimage
for formatting and you need growisofs or 
cdrskin for writing the sessions to media.
This should be ok for at least 50 sessions
per media (the specs indicate more but the
purchasable media are not that good).

Section EXAMPLES of man growisofs says
"
To master and burn an ISO9660 volume with Joliet
and Rock-Ridge  extensions on a DVD:

     growisofs -Z /dev/dvd -R -J /some/files

To append more data to same DVD:

     growisofs -M /dev/dvd -R -J /more/files
"

Hard to surpass in its simplicity.
No explicit formatting needed.
growisofs will operate mkisofs for you.

Caveats:
Do not use option -dvd-compat for multi-session.
I've read in growisofs sources that 9 GB DVD-R DL
cannot do multi-session. 

If you ever use DVD-RW that way, then take care not
to blank them in fast mode. That would make them
single-session only. Rather use 
  dvd+rw-format -blank=full /dev/...
whenever you want to start recording from scratch
(not for appending a new session, of course).

I prefer to format them to overwriteable state:
  dvd+rw-format -force /dev/sr0
This avoids the need for lengthy full blanking before
re-use.


Have a nice day :)

Thomas