FreeLists / openbeosstorage / [openbeosstorage] Re: ISO9660/cdrom progress

["Ingo Weinhold" <bonefish@xxxxxxxxxxxxxxx>]

[...]
> > Er, I probably just don't know about multi-session CDs. A CD 
> > doesn't
> > simply consist of sessions, but these sessions are grouped in 
> > volumes??
> > If that is so, it should be an information the Disk Device API is 
> > able
> > to provide.
> 
> With iso9660 file systems, you can refer to file data from previous 
> sessions instead of duplicating the same data over again.  So, say 
> you 
> have 20 files that you back up on a CD.  Then a week later, you want 
> to 
> back them up again, but only one of them has changed.  Instead of 
> writing all 20 files again, only the changed file will be written, 
> and 
> the remaining entries will just refer to the data in the previous 
> session. 

Mmh, that doesn't sound like something I like. If I understand you 
correctly, the file system needs to access other sessions than the one 
passed to it.

> So, I think that it's not really a session add-on thing as much as a 
> file system add-on thing.  With iso9660, I believe all the related 
> volumes have a common "volume set" identifier (I'd need to double 
> check 
> this, though).  We'd probably need something similar to be able to 
> distinquish which volumes are part of a set and which volumes are 
> independent.  We'd probably also need a way to designate the 
> chronological ordering of the volumes;  either a datestamp or an 
> ordinal numbering, I suppose.  I'm nearly done revamping the session 
> module, so I could look into the details of how iso9960 handles 
> things 
> after I finish.  Thoughts?      

Can you please elaborate a bit more on this -- best starting with the 
terminology. E.g. what is a volume? Is it a session, a track or a 
partition? What is the volume set identifier -- a string, an int? What 
about the chronological order of the volumes on disk -- is it implied 
(by the order of appearance) or explicit (time stamp)? When should a 
session, volume or volume set (or whatever) be invisible for the user, 
i.e. is the session,... burned latest always the only one visible, or, 
if not in general, under what circumstances? ...?

To save you some time, maybe it's better, if you sent a link. As you 
like... :-)

I really want to understand the problem completely first.

CU, Ingo