Comments on: Packet Writing on CDRW and DVDRW media

By: GNot

GNot — Thu, 15 Mar 2007 05:48:25 +0000

I haven’t used any rewriteable media for a while. I guess it’s time for a test (soon). There might be bugs that need to be reported.
Thanks for your feedback.

By: Laszlo

Laszlo — Tue, 13 Mar 2007 01:45:12 +0000

When trying to mount, I have the same computer lock-up problems jimmy martin mentioned. What’s the fix?

By: GNot

GNot — Fri, 16 Feb 2007 11:06:40 +0000

I would recommend testing it from a console, for example by using the cp command to transfer files to the rewritable medium. Was the medium mounted when you run the chmod command? Maybe you should include the -R (recursive) chmod option. If you have used the UDEV rule as is, does the user who tries to write to the medium belong to the group disk?

By: jimmy martin

jimmy martin — Tue, 13 Feb 2007 20:15:37 +0000

Thanks for the great article. I followed all the steps but when it came to mounting the RW media for packet writing using this command: mount -t udf -o rw,noatime /dev/pktcdvd/pktcdvd0 /media/cdvdrw/

My computer would always freeze up needing a reboot. But I now have a desktop icon that says DVD-RW LinuxUDF. In Nautilus when I click on the RW icon there is a folder there called lost+found.

When I try to drag and drop a file to the disc in Nautius file manager I get an error message:
“Error while copying to “/media/LinuxUDF” You do not have permissions to write to this folder.

Even when I log in as root I get the same message.
Is there a workaround way to remove any root permissions while using a GUI file manager.

I tried this comand: “chmod 777 /media/cdvdrw” but it didn’t work.

Jimmy

By: Claudio

Claudio — Tue, 18 Jul 2006 02:37:33 +0000

Thank’s for this great tutorial. I am new in Linux and it helped a lot! I am using this to make Autobackups for important files with rsync and cron in Fedora 4. Fedora has released the new Kernel 2.6.17 and the module pktcdvd is gone. I am getting this message: “FATAL: Module pktcdvd not found.
Can’t find pktcdvd character device.” I have tried to load the module with modprobe (is it right?) and got the same message. What now? I went back to the 2.6.16 kernel but the update is labeled as “security”.
Thank’s for any help.

By: Gnot

Gnot — Tue, 24 Jan 2006 16:59:14 +0000

It’s always good to hear that things work! Thanks for the comment, walwat. :-)

By: walwat

walwat — Sun, 22 Jan 2006 15:41:39 +0000

Thank You Raul for very helpful page!!! It works.
Maybe I have solution of Francesco’s problem.
Tray as root: pktsetup -d pktcdvd0 && rm -f /dev/pktcdvd && pktsetup pktcdvd0 /dev/hdd
(of course replace hdd with your writing device).
This first create wrong pktcdvd, than remove it and again create but the proper one.
It has to be done after every reboot, so proposed by Raul script in the line creating device mapping can be:
su -l root -c “pktsetup -d pktcdvd0 && rm -f /dev/pktcdvd && pktsetup pktcdvd0 /dev/hdd”
insted of: su -l root -c “pktsetup pktcdvd0 /dev/hdd”.
You can also do: pktsetup pktcdvd0 /dev/hdd && rm -f /dev/pktcdvd && pktsetup pktcdvd0 /dev/hdd.
Obviously there is a bug in pktsetup.
I hope it will help and thanks again Raul.

By: Gnot

Gnot — Tue, 03 Jan 2006 16:37:01 +0000

Unfortunately I cannot provide any more help. I am out of ideas... Perhaps you should also try adding one of the following lines to /etc/modprobe.conf or /etc/modules.conf: alias block-major-97 pktcdvd or alias block-major-252 pktcdvd I believe that you need a newer kernel version.

By: Francesco

Francesco — Mon, 02 Jan 2006 19:53:25 +0000

Slackware 10.1 uses by default the kernel 2.4.29 and in testing the 2.6.10 (even if a lot of person find this more stable than the 2.4). The two kernels are vanilla ones. For this reason it seems there is a mix between udev and devfs. In /etc/udev/rules.d the file for the rules isn’t 50-udev.rules but conf-udev.rules or something similar that I had already renamed in 50-udev.rules and I had already tried to put your rules in 10-udev.rules but unfortunately nothing changes. I have said that probably there is a mix between devfs and udev since there are some files in /etc/udev/rules.d called “devfs.rules.unsupported” and “/etc/udev/rules.d/compat.rules.unsupported”. Anyway these files don’t deal with pktcdvd and when I give the command “pktsetup pktcdvd0 /dev/hdc” are correctly created the two file /dev/pktcdvd/pktcdvd0 and /dev/pktcdvd/control.
The version of pktcdvd is “0.2 a” and the kernel I’m using is the 2.6.13.2 compiled by myself with abilitated the udf fs and the pktcdvd (not as modules. They are in the kernel). I’ve tried to use the dvd but there is the same problem: altough the cp command has finished the led of the dvd-writer is always on since I’have copied the files. I’ll try to post to the packetwriting mailing list. Thank you anyway…

By: Gnot

Gnot — Mon, 02 Jan 2006 03:15:32 +0000

Hi, Francesco. I am not surprised that the kernel pktcdvd module has got you into trouble. I had many issues, until it worked properly. The first thing that needs to be settled is the proper creation of the device nodes in /dev/. If there are no UDEV rules, then it's most probable that the necessary device nodes will be created in the wrong place. The creation of the /dev/pktcdvd/ directory is handled by UDEV, so creating this directory in rc.local is not needed. You should also check if there are any default UDEV rules for pktcdvd. Maybe you will need to rename the file with the rules I have suggested to 40-udev.rules or anything that will be read before the default 50-udev.rules file. You have written that you have resolved your issues with the device node creation, but I just added this info. Now, for the other problems you have encountered: Make sure, through a Slackware mailing list or by any other means, that the version of the pktcdvd module that is included in your running kernel version is functioning properly and that no issues have been reported about it. This is critical. I had encountered the same problem (the drive led wouldn't stop blinking), probably to malfunctioning pktcdvd module. This had happened only once, but I cannot remember the version of the kernel... Second, make sure that your kernel has support for the UDF filesystem. If the udf module does not get loaded together with the pktcdvd module when you setup the device mapping, then try to load it in rc.local. About cdrwtool, as I have written in this article, I could not make it prepare my CDRW media for packet writing. I do not know which exactly is the problem, but I guess that it does not work well with my DVD writer. I can tell you, that I had almost quit due to these damn cdrwtool malfuctions and its non-informative error messages. I would suggest that you try some DVD rewritable media instead. dvd+rw-tools seem to be much more stable, but you can use them only with DVDRWs. I currently do not use any CDRWs because of the little storage space they provide. A last thing I would suggest is to try to copy some files to the rewritable medium using cp, instead of konqueror or any other graphical file manager, just to make sure that it works. I hope these will help. It is very difficult to tell what exactly is wrong. It may need some time until you investigate your issue.