Information Technology

The fact that the idea of free software is so contrary to the behavior of Microsoft is exactly reflected by how their respective representatives act in their talks. Here’s a quick video edited by myself from sources I found on YouTube:

It’s totally up to you who you trust.

I complained about my old notebook being too slow at image processing. As I now run a new machine, it’s time to measure the performance increase:

Old system: 1×1.6 GHz CPU, 1 GB RAM
New system: 8×2.67 GHz CPU (by threads), 6 GB RAM
Test file sizes: 11.2–12.5 MB

Task #1: Render 8 RAW images to PPM in multi-parallel
Command line:

Old system time: 1 min 41.1 sec
Old system mem usage: 1 GB (100%)

New system time: 0 min 04.6 sec
New system mem usage: 2 GB (33%)

→ 22× faster

Task #2: Render 8 RAW images to JPEG in multi-parallel
Command line:

Old system time: 5 min 0.0 sec
Old system mem usage: 1 GB (100%)

New system time: 0 min 18.2 sec
New system mem usage: 2.5 GB (42%)

→ 16.5× faster

Hell yeah!

Debian’s standard kernel 2.6.26 has a little drawback: The coretemp module doesn’t recognize Intel’s Core i7 processor. The sensor chip W83667HG of my Asus P6T Deluxe (LGA 1366 socket) is not yet supported as well. This is a typical symptom when using Linux on too recent hardware. However, if it’s enough for you to read an aggregated CPU temperature instead of eight individual core temperatures, you can force loading the w83627ehf module with

and tune the /etc/sensors3.conf to get rid of false alarms.

Luckily, for the current prerelease 2.6.29-rc6 there’s a very recent bunch of patches available that brings support for W83667HG into the w83627ehf module, whereas coretemp already finds the CPU. Follow this guide on how to compile and install a new kernel the Debian way. A drawback is that source modules from the official Debian repositories might not compile anymore, e.g. the MadWifi modules. You have to get them from the project directly (via SVN). You also need to build a current version of lm-sensors (via SVN) to correctly gather the values from w83627ehf. You could then visualize the values e.g. with gkrellm.

Now have fun stress-testing your system with MPrime.

Update 03/24: It appears that these patches didn’t make it into the final 2.6.29 release.

Update 04/09: The patches went into 2.6.30-rc1.

Because it’s a pain, a short reminder for myself on how to connect a Bluetooth capable cell phone with a Debian box:

1. Install bluez-utils.
2. Read this (German) guide and follow instructions, but ignore the obsolete stuff about the pin helper; today it’s just an entry like passkey “1337”;
3. For whatever reason, hcid doesn’t launch a passkey-agent automatically. For the very first connection, you have to do it by yourself:
1. Get both the passkey-agent.c.gz source and its Makefile from the bluez-utils examples directory and compile it; you’ll need libdbus-1-dev.
2. Launch it as /path/to/passkey-agent 1337 HA:RD:WA:RE:AD:DR and go to a different shell.
4. cat < /dev/rfcomm0 and enter the requested pin on your cell. If nothing special happens, you’re done.

In your cell’s Bluetooth settings you could now permanently authorize your PC. The next cat < /dev/rfcomm0 shouldn’t initiate a pin request anymore.