Re: tlug: CD Roasting with xcdroast 0.96c

[Jim Tittsler <jwt-tlug@example.com>]

On Mon, Oct 27, 1997 at 11:01:53PM +0900, Dennis McMurchy wrote:
>   I'm having a few problems with CD Mastering ( which uses the  mkisofs
> 1.11 to do the nitty-gritty) that I haven't figured out yet.  A single
> file in 100s of megabytes will contain an error that makes it
> unreadable (this is not a CD-writing error, but an error in the image

I've not had that problem... but I've not moved to 1.11.

>   What I really wanted to ask about, was if anyone knows how I can
> access the tracks of a multi-session CD beyond the first track.  You

The table of contents for a multisession disc is built by the drive by
scanning all of the TOCs from first to last.[*] It returns the TOC of the
complete disc unless explictly told otherwise... making reading multi-
session discs quite transparent.  The primary volume descriptor in the last
sesssion is the one that is used when "mounting" the disc.  A data disc will
simply look like a larger piece of media after finalization of the session
or an audio disc will have more tracks.  The tracks are numbered in
increasing (but not necessarily contiguous...**) order.

(Before Multisession discs became common, there were multiple session discs,
each with their own tracks... but this rapidly died out when multisession
was widely adopted... and I don't believe it is even implemented in Linux.
We did have drivers for DOS and OS/2 that took a "session" argument... but
that support has been abandoned.  There is now a "skip" mark that can be
used logically delete earlier tracks in the audio case.)

> And, of course, when you 'mount' a CD with multiple tracks, you only get
> the first track.

Of course, that is not true.  :-).  The ISO9660 file system (which is what
controls what "you get" in the data sense) allows the data to span multiple
tracks.

Jim

[*] This is why it takes so long to "initialize" when you put a multisession
disc in a CD-ROM drive.  It has to read each of the TOCs, and only knows
that it has reached the "last" one when it fails to read a "next" one...
and it needs to do enough retries to be sure the head is where the next
one really ought to be and that it isn't just a marginal read error.

[**] Although they better be if you want to be able to read the discs
on all drives. :-)

Next TLUG meeting is Saturday Dec. 13, 1997  (possibly Nov. 13?)
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