Linux

Wetterstation mit dem Raspberry Pi

Da mein geliebter Linksys NSLU leider den Geist aufgegeben hat. Suchte ich nach einem würdigen Nachfolger und wurde beim Raspberry Pi fündig.

Heute habe ich endlich mal Zeit gehabt den Code vom USB-Stick des NSLU auf die SD-Card des RPis zu spielen. Und - Linux sei dank - bis auf eine winzige Änderung am Ruby Skript läuft alles wie zuvor. Die Änderung ist wohl eher dem Sprung von Ruby 1.8 auf Ruby 1.9 zu verdanken. Sonst wäre das Programm wohl einfach so gelaufen.

Bald ist meine Wetterstation wieder online.

Calculator for Linux Huge Page Table Config for Java JVMs

You can speedup Java processes that handle a big heap (several gigabytes) by configuring Linux and the JVM to use large memory pages. This minimizes the load on the TLB tables (which can hold only a limited number of entries) of the processor. For applications that don't have localized memory structures you can easily see a speedup of 50-100% because of the trashing of the TLB caches! But the speedup depends on the type of application you are running of course.

Enable WPA encryption on an USR5410 WiFi card under Ubuntu 7.10 and ndiswrapper

I own a US Robotics USR5410 wireless LAN card and wanted to get it running with WPA encryption under Ubuntu Linux.

Here is what I have done to achieve this:

You have to set the default driver for this card (called acx) to the modules blacklist. It has no support for WPA encryption. To achieve this do sudo vi /etc/modprobe.d/blacklist and add the line blacklist acx. Plug the card in and reboot.

OpenWRT on an Siemens Gigaset WLAN Repeater 108

I own two Siemens Gigaset WLAN Repeater 108 devices. They run fine but use a proprietary firmware from Siemens. I now started to experiment if I can get OpenWRT running on them.

Some impressions of the device...

Outside:

Inside:

The serial console connector we need to hack the device:

an alternate shot:

Copy a Linux installation with ext2/3 filesystem to a bigger harddisk

As I am running a Linux VDR installation with an old IBM Deskstar 40GB harddisk. The problem with this harddisk is that it is very small when you use VDR's autotimer functionality and it is far too loud for my living room. My new harddisk is a Samsung SP2514N with 250GB. This drive is very silent. When it is switched on you are wondering if it is really running.

dbox2 Linux Wiki

I have installed Linux on my old Nokia dbox2. It is now usable at last. The orginal software on that box is a piece of crap.
See dbox2 Linux Wiki for details. Some crazy people have found a way to install a harddisk into that box.

The LCD of the box looks like this while booting...

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