Jimmy's weblog


Presentations with acroread

Filed under: — jimmy @ 2:43 am

I usually give my presentations with acroread. Sometimes it’s comfortable to walk around in the room but still be able to switch between the slides. Unfortunately neither acroread nor xpdf support switching with a mouse or any other pointer device. But there’s this nice tool called imwheel. It allows to map mouse buttons to keys, like mapping the mouse wheel to page-up/page-down. This is done with a file .imwheelrc in your homedirectory, looking similiar to this:

None,     Button4,     Page_Up
None,     Button5,     Page_Down

After starting the imwheel daemon you can now use the mouse wheel for switching between slides. For pointer devices that have only buttons you simply can swap mouse buttons with xmodmap.

xmodmap -e "pointer = 4 2 5 1 3"

Now you can use the left and right mouse button for switching. Simply turn it off again by executing:

xmodmap -e "pointer = 1 2 3 4 5"


OS04 and grml 0.1 release

Filed under: — jimmy @ 11:54 pm

On Friday I was giving a talk about games under linux at OS04 There have been a lot of interesting talks this day and it was really hard to decide which talk to listen to. Would be easier to be at two or three places the same time ;-)
The first talk was about Irrlicht, an open source 3D game engine. I was really impressed when listening to Nikolaus Gebhardt’s talk.
Afterwards I could learn a lot of new tricks for gimp, thank you Wolfgang Scheicher :-)
After the first break Rene Mayrhofer talked about his project/product Gibraltar firewall, a firewall running off cdrom and based on Debian, also including a web front-end for setup and maintenance. I was able to get one of the free CDs, I really have to check this out.
The next talk was held by Gerfried Fuchs, he talked about the Debian GNU/Linux project. A very good presentation of debian, IMO.
The last talk I was listening to was Michael Prokop’s talk about grml, a live-cd based on knoppix and debian, optimized for system administrators. Since I’m in the grml-developer team I was very curious about the public interest in grml. Mika gave an overview of grml and handed out CDs of the 0.1 release, which we especially released for OS04. Nice talk, mika :-)
I really enjoyed OS04. It was well organized and there’ve been a lot of interesting people and projects.

LVM-root nightmare

Filed under: — jimmy @ 11:13 pm

This Monday I decided to convert my ext3 root filesystem to “lvm-on-raid-root”… bad decision. I was familiar with converting root filesystems to raid-root filesystems, this was done in a few minutes. I thought it would be easy too, to make a lvm root filesytem on top of it. It took me about 4! days! to make it work. A lot of troubles arised because I was not aware of the differences between lvm1 and lvm2. It’s not only the difference in the meta-data, it’s also important to use the right tools, e.g. I was not able to use the lvm1 tools for a lvm1 that was created with the lvm2 tools(-M lvm1). Another problem was that you need a initrd, also when all the modules are compiled in your kernel because the kernel can’t activate the volume groups itself. So you need an initial ramdisk that calls the necessary commands. Again, there is a version for lvm1 and another one for lvm2, which is not included in the debian binary package lvm2, but it’s available in the source.
When you want to convert your system to lvm-on-raid-root you should be very careful. You should backup your harddisk with dd, so it’s aways possible to undo the changes. Also have a good alternative for booting the system if it fails. I used grml because I was missing the lvm tools in knoppix. This was the right time for testing the grml 0.1 release, I was really glad that I had it :-) .
There are a few good Howtos about lvm and raid, unfortunately I’m missing information about lvm2 initrd.
This one was a good guide.
This posting finally saved my life. Thank you Alasdair G Kergon, without your answer I would still try to make a script for creating the initrd :-)


OpenGroupware: init scripts for debian

Filed under: — jimmy @ 9:05 am

There are a few init scripts for starting and stopping OpenGroupware available on the net. But I only found one, that is using start-stop-daemon, unfortunately it doesn’t support logging. So I wrote my own init script, which also uses a file in /etc/default to set the most important variables, like the ports for opengroupware and zidestore. You can download the script on my homepage, it’s located here.


Backup system

Filed under: — jimmy @ 8:28 am

I’ve always been looking for a small backup tool, that just makes an archive of some folders and sends it to a specific host. And here I finally found one, called backup-manager. Now I’m able to make a backup of the most important data on all of my servers and get the compressed archives sent to my main server. Backup-manager is the ideal tool for that job and it’s setup in about five minutes :-)