------------------------------------------------------------------------
Tracey DeLaney                                 Harvard-Smithsonian
tdelaney@cfa.harvard.edu                   *     Center for Astrophysics
Phone:    (617) 496-1985     *    *   *     *  60 Garden Street, MS 67
Fax:      (617) 496-7969  *             *      Cambridge, MA  02138  USA
------------------------------------------------------------------------

I found a nice explanation for setting up udf writing at
http://w1.894.telia.com/~u89404340/packet.html and
http://cvs.linuxfromscratch.org/index.cgi/hints/Attic/cdrw-hint.txt?rev=1.3

basically:
1.  need to patch the kernel
2.  need the packet writing tools
3.  need to set everything up properly
The usenet archive is pretty useful if you have problems
http://lists.suse.com/archive/packet-writing/
note that these newer versions support writing to CD as well as DVD

the whole process is (borrowing hints heavily from sources above):

1.  get the appropriate kernel patch at
http://w1.894.telia.com/~u89404340/patches/packet/
for kernel 2.6.8 specifically
http://w1.894.telia.com/~u89404340/patches/packet/2.6/packet-2.6.8.patch.bz2

2. Become superuser and move to your linux source directory, then
   apply the patch with:

       'patch -Np1 -i packet-2.6.8.patch'

3. Now run 'make xconfig', or whatever version of kernel config you use
   such as 'make menuconfig'

   Go to the section on 'Block Devices' and select:
       Packet writing on CD/DVD media

   Now go to the section on 'File systems' and select the following:
       UDF files systems support (read only)
       UDF write support (DANGEROUS)

   Despite the note on this latter option saying it only applies to
   fixed disks and DVD-RAM, the patch will make it work with CD-RW too!

   Select 'Save and Exit'

4. build your new kernel with:

       'make bzImage'

4. then copy the resulting kernel to /boot as, say, vmlinuz-2.4.19-UDF.

5. If you are using modules, you now need to

     'make modules'
     'make modules_install'

   The packet writing module is called pktcdvd.o.

6. set up your boot loader to be able to boot either your old
   kernel or this new one. (Always keep the old kernel bootable, just in
   case...)

7. Now reboot with the new kernel, it should be almost identical to your
   old one.

8. if you built the packet driver as a module and you have kernel < 2.6.8,
   you need to add:
    alias block-major-97 pktcdvd
   to your /etc/modules.conf file or /etc/modprobe.conf
   depending on linux version.

9. if your kernel is less than 2.6.8, make the packet driver device file
   As superuser, make the file(s) in /dev with:

     'mknod /dev/pktcdvd0 b 97 0'
     'mknod /dev/pktcdvd1 b 97 1'
     etc...

   If you want ordinary users to be able to use CD-RW, DVD+RW, or DVD-RW too,
   then:
   'chmod 666 /dev/pktcdvd*'

   if your kernel is >= 2.6.8, make the directory /dev/pktcdvd and adjust
   the permissions for ordinary users

10. need UDF packet writing tools from
        http://sourceforge.net/projects/linux-udf
        the 2 files are:
                udf-0.9.8.tar.gz (this just lets the system
		understand udf - not necessary on newer systems)
                udftools-1.0.0b3.tar.gz (necessary to write udf)

   Unpack this is the usual way and build it with:

    './configure --prefix=/usr &&'
    'make &&'
    'make install'

   You now have three new programs (in /usr/bin if run as above), complete
   with man pages:

   cdrwtool - a tool to do various jobs on your CD-RW drive and disks.
   mkudffs  - to create an UDF filesystem (on your hard disk if you want)
   pktsetup - a tool to setup and tear down packet drive associations.

   need to possibly patch udf tools depending on kernel
   for kernel 2.6.8 use:
   http://w1.894.telia.com/~u89404340/patches/packet/udftools-1.0.0b3.patch.bz2

11. If you have kernel >= 2.6.8, after reboot, there should now be a
    directory /dev/pktcdvd with a char device 'control' in it.

12. as superuser, you may need to suid the pktsetup program.  This gives
    normal users the ability to execute tasks they would normally not be
    able to do because of tight file permission schemes.  There are security
    concerns with using the suid option.  But if you do need it, the process
    is:
      become the superuser
      'chown root /path_to_pktsetup/pktsetup'
      'chmod 4755 /path_to_pktsetup/pktsetup'

13. Now to actually run the programs:

    Lets suppose you have a CD-RW disk straight out of the box, and want to
    prepare it for use.  You must first format the disk.  If your CD-RW drive
    is on /dev/scd0 (treated as a scsi device like older versions of linux),
    then:

       'cdrwtool -d /dev/scd0 -q'

    If your CD-RW is on /dev/hdc (treated as an ide device like newer
    versions of linux), then:

       'cdrwtool -d /dev/hdc -q'

    the -d is for device, the -q is for quick setup

    alternatively, 'dvd+rw-format /dev/hdc' if you have this program

    Now set up the packet writing device:

       'pktsetup /dev/pktcdvd0 /dev/hdc' for kernel < 2.6.8
       'pktsetup pktcdvd0 /dev/hdc' for kernel >= 2.6.8

    this associates a packet-driver with your CD-RW drive (this doesn't
    survive a reboot).

    To make sure things are going well, do (for kernel >= 2.6.8):

      >'ls -l /dev/pktcdvd/pktcdvd0 /dev/hdc'
      brw-------  1 root     disk  22, 0 Feb 23  2004 /dev/hdc
      brw-r-----  1 root     root 252, 0 Nov  9 09:39 /dev/pktcdvd/pktcdvd0

      and
      >'pktsetup -s'
      0 : 252:0 -> 22:0

    Now set up the udf filesystem

      'mkudffs /dev/pktcdvd/pktcdvd0'

    Now mount the device
      'mount /dev/pktcdvd0 /mnt/cdrom -t udf -o rw,noatime'

    Your CD or DVD whould be mounted as a read-write filesystem, all ready
    to use, just like any other hard disk.  You should be able to cp, mv, or
    create files directly on your DVD or CD. ('noatime' just speeds things
    up by not updating the access times, CD-RW can be a little slow)

    Then you can 'umount /mnt/cdrom' in the usual way, when you're done.

    Normally the mount command above is not allowed for normal users.
    In this case, I suggest setting up a new fstab entry such as

    /dev/pktcdvd/pktcdvd0   /mnt/dvd  udf  noauto,users,rw,noatime 0 0

    then the simple 'mount /mnt/dvd' can be issued by anybody.

    To tear down the packet writing device, issue the command:

       'pktsetup -d 252:0'

14. AIPS specific setup:
    a. create a link in the aips/DATA area just as you have for your hard
       disk areas, for instance:

	    'ln -s /mnt/dvd COMPUTERNAME_3'

       and make the necessary entries in the aips/DA00/NETSP and
       aips/DA00/DADEVS.LIST

    b. run pktsetup and mount your udf formatted DVD

    c. cd to /mnt/dvd and create the empty SPACE file with appropriate
       permissions - I suggest rw for all

    d. start AIPS in the usual way
       at startup, the DVD disk should be found

    e. transfer files to the DVD disk as you would for any other disk
       MOVE, SUBIM, UVCOP, ...
       Although possible, I would suggest not "working" directly on the DVD
       because it is slower and also because there are limited rewrites for
       RW media.

    f. exit from AIPS, cd to /mnt/dvd, and make sure the permissions on your
       new files are rw for all.  This will allow you to transport your DVDs
       to different facilities or between work and home or onto your laptop
       without permission problems.

    g. unmount your DVD, and tear down the packet device

--- end