Mini Shell

This is from "Eduardo M. A. M. Mendes" <mendes@mgconecta.com.br>

Creating multi-session CD's with dir=/ feature Micro Howto

This mini-howto was written as guide to help me to create multi-session CD's
with the possibility of determining the location of files. I hope
that this guide helps you too.

In order to use wodim it is first necessary to define to which scsi bus
the cd-writer is connected. In my case the setup is dev=0,3,0. It is also
interesting to have a separate directory in which all image files can
be dumped: /home/cdsource is the directory I chose for dumping the images.

The best way to understand how to create multi-session cds is to read
README.multi. Most of what is going to be said here is based on that
README file and on the help of several wodim users. 

This Micro Howto is divided into two parts as follows:

Example a) A dir/=/dir1/dir2 example

Example b) A dir1/dir2/=/dir3/dir4 and dir1/dir2a=/dir5/dir6 example


We are now ready to start.

Example a) An dir/=/dir1/dir2 example

A simple example will demonstrate that we can create multi-session cds 
with the dir_feature of the type dir/=/dir1/dir2

Objetive: Saving root directories of Redhat 6.1 and Col 2.3 on a single CD.

Observation: Redhat installation is mounted on COL 2.3 at /mnt/redhat

First image - RedHat 6.1 - /mnt/redhat/root

genisoimage -D -l -r -f -m core -L -o image1.raw redhat/=/mnt/redhat/root

This will create a redhat directory on the cd. The option -D should be
used with care. The other options used in the above command are just 
to demonstrate the use of genisoimage.  Please
refer to man genisoimage if you want to know more.


To see if the image is created as expected, we need to mount image1.raw using
the option -o loop (Linux only! for information on Solaris read README.verify)
as follows:

mount -t iso9660 image1.raw /mnt/image -o loop

To see the contents type:

ls -l /mnt/image/redhat

Does it look ok?  Great! Unmount /mnt/image. Now the burning process itself:

wodim -v -dev=0,3,0 -multi -eject image1.raw 

To check the burned image we need to mount the cd; something like

mount -t iso9660 /dev/scd0 /mnt/cdroms

/mnt/cdroms is the device file for the cdrom I use.


Second image - Caldera 2.3 - /root


To create the second image on our cd, we need get information
about sectors related to the first track. To do that, issue the command

wodim -v -dev=0,3,0 -msinfo 

wodim returns the following number

0,135563

This number is the format XX,YY discussed on README.multi.  XX would be used
for testing the images as well as burning the new track.

genisoimage -D -l -r -f -m core -L -C 0,135563 -M /dev/scd0 -o image2.raw  caldera/=/root

Now we need to check of image2.raw is ok. The following command creates exactly what we 
need.  Plese note that -C option. Only the first number changes in this case. The second one
is always zero.  In our case the first number is zero due to wodim -msinfo.  When 
more tracks are added to the cd this number will change.

genisoimage -D -l -r -f -m core -L -C 0,0 -M /dev/scd0 -o image2_test.raw  caldera/=/root

mount -t iso9660 image2_test.raw /mnt/image -o loop

ls -l /mnt/image shows that there are two directories: redhat and caldera, just the way
we wanted.

Now let us burn image2.raw (not image2_test.raw)

wodim -v -dev=0,3,0 -multi -eject image2.raw

We can mount the CD again to see that the two directories are there.  We can carry on
doing this until we decide to close the CD. If this is the case, don't use -multi when
burning the last session.

b) A dir1/dir2/=/dir3/dir4 and dir1/dir2a=/dir5/dir6 example

The above example seems a bit silly, one could argue. Why did I create a single directory
called root and within two sub-directories: redhat and caldera?  

Using the procedure described above we would do as follows:

genisoimage -D -l -r -f -m core -L -o image1.raw etc/redhat/=/mnt/redhat/etc

wodim -v -dev=0,3,0 -multi -eject image1.raw 

To check the burned image we need to mount the cd; something like

mount -t iso9660 /dev/scd0 /mnt/cdroms

wodim -v -dev0,3,0 -msinfo 

wodim returns the following number

0,14391

The second image can be created using

genisoimage -l -r -f -m core -L -C 0,14391 -M /dev/scd0 -o image2.raw  etc/caldera/=/etc  

Creating a test image2

genisoimage -l -r -f -m core -L -C 0,0 -M /dev/scd0 -o image2_test.raw etc/caldera/=/etc 

mount -t iso9660 image2_test.raw /mnt/image1 -o loop

It works!!   That is great!!!

Now the burning process itself.

wodim -v -dev=0,3,0 -multi -eject image2.raw

and we're done !!!!

To add more tracks just do as indicated above.

Good luxk!!!

Eduardo Mendes - 11/23/99

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