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✏️ Editing: README.session

/* @(#)README.session	1.3 99/03/02 eric */

This release of genisoimage has basic support completed for
multiple sessions.  However, we still need some interaction 
between wodim and genisoimage for this to work correctly. This is needed as
only wodim knows the different ways to gather these numbers for all 
different drives. It may be that future versions of genisoimage will include 
the needed support for MMC compliant drives.

There are a few new options to genisoimage to allow for this.
The first one is "-M /dev/scd0", and is used so that genisoimage can examine
the entirety of the previous image so that it can figure out what additional
files need to be written in the new session. Note that there are operating
systems that don't allow to read from CD drives with a sector size
of 2048 bytes per sector. To use genisoimage on such an operating system, you
will need a version of genisoimage that includes the SCSI transport library 
from wodim. Simply use the dev= syntax from wodim with -M in
such a case. It will tell genisoimage to use the SCSI transport library to 
read from the CD instead of using the standard read() OS interface.

There is also a temporary hack in genisoimage in the form of a '-C' option.
The -C option takes two numbers as input, which are delimited by commas.
For example, you could specify "-C 1000,1020", but you should never just
make up numbers to use here.  These numbers are determined from wodim.

Note that if you use -C and omit -M, it effectively means that
you are writing a new session, starting at a non-zero block number,
and you are effectively ignoring all of the previous session contents.
When this session is sent to the writer, the new session effectively
"erases" the previous session.

In practice you should be able to do something like:

genisoimage [other options] -C `wodim dev=b,t,l -msinfo` \
		-M /dev/cdblkdev

Replace 'b,t,l' by the aproriate numbers for SCSIbus, target and lun
of your drive.

Note: As of the 1.12b5 release, the multi-session technology has
matured quite significantly.  It is entirely possible that bugs
exists, or that further tweaks will be required somewhere along the
way to get things working correctly.  The data gathering mode of
wodim has been tested, and I believe it works correctly.  Caveat
Emptor.

[Mar 1, 1999].

Source: README.session from cdrtools package
Edited for cdrkit by Christian Fromme <kaner@strace.org> and 
Eduard Bloch <blade@debian.org>

MR SKB