The Linux kernel has for quite a while supported packet writing on writable (and rewritable) CD's and DVD's. Packet writing means that you can write to a CD/DVD in the same way you would write to a usb key, for example. So you no more need to create ISO-images and burn them onto discs, which is very clumsy and slow. The downside is that the discs you write will not probably work on CD/DVD drives which do not support packet writing or do not have packet writing software installed.
This howto is meant especially for Debian Sarge (3.1), but you might find it useful even if you have some other Linux distribution.
UPDATE (18.7.2007): Having tested packet writing extensively, I've noted that various drives have variable support for packet writing. Although in theory almost all current DVD writers should support packet writing, some work quite well, while others work, but not well enough to be useful. Many drives burn ordinary DVD's just fine, but choke into I/O errors when using the Linux packet writing device. I guess this all comes down to buggy DVD-drive firmware. The bottom line is that If packet writing does not work on your drive, first try to upgrade the drive firmware. If that does not help, probably nothing will. Be prepared to connect the drive to a Windows box, as the firmware updater is most likely a Windows-only proprietary program.
Packet writing requires support from the Linux kernel. You should first verify your kernel version:
localhost:/# uname -r 2.6.17-ipsec localhost:/#
If you are using the Debian standard kernels then this howto may not be useful to you, as the older 2.6.x kernels (such as Debian 2.6.8) handle packet writing a bit differently. In fact, on stock Debian kernels packet writing might work out of the box, but it did not work with my 2.6.17 kernel.
Next you should check if you have packet writing and udf modules loaded:
localhost:/# lsmod|grep udf udf 72516 0 localhost:/# lsmod|grep pktcdvd pktcdvd 22972 2 cdrom 33760 2 pktcdvd,ide_cd localhost:/#
If the modules were not loaded, try loading them with "modprobe udf pktcdvd". If you get error messages, such as FATAL: Module pktcdvd not found. then there you might have a problem. It is, however, possible that the driver is not compiled into a module, but straight into the kernel. Nowadays most drivers are compiled as modules, so it is quite likely that you'll have to build your own kernel or get a kernel that has packet writing support. In case you decide to build your own kernel, try googling with words "linux kernel compile" to find some thorough documentation. I can only give a quickstart...
First grab the most recent kernel sources you can find from http://www.kernel.org. Copy the kernel source package to /usr/src and issue the following commands:
localhost:/# apt-get install kernel-package localhost:/# cd /usr/src localhost:/usr/src# tar -jxf your_new_kernel_package.tar.bz2 localhost:/usr/src# rm /usr/src/linux localhost:/usr/src# ln -s your_new_kernel_tree linux localhost:/usr/src# cd linux localhost:/usr/src/linux# make menuconfig
While in kernel configuration menu make sure that you select at least the following:
Consult Kernel compilation HOWTO's and guides for all the other choices you have to make. The amount of choices and terms may seem daunting at first, but once you do it a couple of times it gets much much easier. When you've done with the kernel configuration, save the config and exit.
Now we'll compile and install the kernel "the Debian way" with following commands:
localhost:/usr/src/linux# make-kpkg --append-to-version "custom" kernel_image localhost:/usr/src/linux# cd .. localhost:/usr/src# dpkg -i your_kernel_package.deb
If you use grub, you should be ready to go. If you don't trust the dpkg's grub update you probably want to check that /boot/grub/menu.lst is setup correctly.
That's it, now do a reboot. If you get weird behaviour and/or kernel panic, read through the Kernel compilation guides once more and reconfigure the kernel again and again until you get a functional system :).
In addition to kernel modules we need a software package called udftools. It is in fact the only piece of software we need in addition to basic Linux tools. If you are using the 2.6.8 kernel that comes with Debian Sarge then you should first try installing udftools with apt-get. I did not have any luck with the Debian version so I had to compile my own udftools.
If Debian udftools doesn't work for you, get the latest version from http://sourceforge.net/projects/linux-udf. To get my udftools to work I had to download a patch from http://web.telia.com/~u89404340/packet.html. You should first compile the udftools without the patch and try if it works. If it doesn't, then apply the patch.
UDFtools is quite simple to install. Just unpack the udftools-1.0.0b3.tar.gz (or whatever version is current) and do a
localhost:/home/samuli/Downloads/udftools-1.0.0b3# ./configure;make;make install
If you find out that you need the patch, do as follows:
localhost:/home/samuli/Downloads/udftools-1.0.0b3# patch < udftools-1.0.0b3.patch
When it asks which file to patch, enter pktsetup/pktsetup.c. It should then apply the patch. Next do the following to reconfigure and recompile udftools:
localhost:/home/samuli/Downloads/udftools-1.0.0b3# make uninstall localhost:/home/samuli/Downloads/udftools-1.0.0b3# make clean localhost:/home/samuli/Downloads/udftools-1.0.0b3# ./configure;make;make install
Now that udftools is installed, we'll have to configure the packet writing device.
UPDATE (18.7.2007): On Debian Etch (4.0) and Ubuntu (at least 6.10+) you only need to edit /etc/default/udftools to enable packet writing. After modifying this file just restart the udftools service and everything should be taken care of for you.
Recent 2.6.x kernels add packet writing devices to /dev/pktcdvd. For example, the first packet writing device is called /dev/pktcdvd/0, the second one /dev/pktcdvd/1 etc. In older 2.6.x kernels the devices were called with names such as /dev/pktcdvd0. Before you proceed, check that you don't already have the required devices:
localhost:/# ls -l /dev/pktcdvd/ totale 0 brw-rw---- 1 root cdrom 254, 0 2006-08-06 09:46 0 brw-rw---- 1 root cdrom 254, 1 2006-08-06 09:46 1 crw-r--r-- 1 root root 10, 63 2006-08-06 09:45 control localhost:/#
In this case the devices are already present, so the rest of the chapter can be skipped.
Each packet writing device has to be bound to a physical device, such as /dev/hdd (slave device on second IDE channel). This is done with the program pktsetup, which comes with the udftools package. It is quite simple to use:
localhost:/# pktsetup 0 /dev/hdd localhost:/#
You can replace the "0" with another number if necessary (see below). I had problems with this exact step, but after patching udftools they disappeared. If you try to bind a physical device to a packet writing device that is already in use, you'll see the following error:
localhost:/# pktsetup 0 /dev/hdd Device node '0' already in use localhost:/#
For some reason my udev does not create the necessary entries in /dev/pktcdvd. I did not want to mess with udev entries so I added two commands in /etc/init.d/rc.local, which I use as a custom startup file:
#!/bin/sh # /etc/init.d/rc.local case "$1" in start) pktsetup 0 /dev/hdc pktsetup 1 /dev/hdd ;; stop) echo "Removing custom settings" ;; esac exit 0
If you don't already have a similar startup file, do as follows after you've created the file:
localhost:/# chmod 755 /etc/init.d/rc.local localhost:/# update-rc.d rc.local defaults
See "man update-rc.d" if you run into trouble.
When the packet writing device is ready, it's time to grab an empty DVD. I have mostly DVD+RW's so I can't comment on how other media works with packet writing. First you'll need to format the media and then create an udf filesystem on it:
