linux-3.8.4: Compile times

21st March 2013

In Phoronix Forum I have received feedback regarding the CPU time issue, as described below, see "CPU Usage Time Is Dependant on Load". Right now I use 3.2.0-38-generic #61-Ubuntu SMP Tue Feb 19 12:18:21 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux So maybe this behaviour is kernel dependant.…

Screenshots on Nexus 4 (Android 4.x)

13th March 2013

Press On/Off switch (right) and simultaneously press speaker volume button (left), voila, you've got your screenshot in Android. Here is an example from today.

Google Search says "Happy Birthday"

13th March 2013

Download "Sent Mail" from Google Mail via POP3

8th March 2013

It is easy to download received e-mail from GMail. It is not obvious how to download ones own sent mail. To do this you have to "Enable POP for all mail (even mail that's already been downloaded)" in the Setting's area, see picture below.

Fon and Deutsche Telekom Partner Together in Germany

5th March 2013

Yesterday Fon and Deutsche Telekom announced that Deutsche Telekom wants to partner with Fon. Fon already partnered with British Telecom, with Portuguese Zon, with Belgian Belgacom, French SFR, Croatian (Deutsche) Telekom, and others. Fon already partnered with E-Plus in Germany. But this…

GTC 2012 Keynote by Jen-Hsun Huang (Part 03): The NVIDIA Kepler GPU Architecture

5th March 2013

NVidia CEO Jen-Hsun Huang speaks on GTC (GPU Technology Conference (dead link)) 2012 on key differences between Fermi and Kepler. Key differences are SMX: Streaming Multiprocessor neXt generation Hyper-Q: keep GPU busy with queuing Dynamic Parallelism: GPU can now assign work to itself, e.g., run…

Possible Enhancements to J-Pilot

27th February 2013

Here are some thoughts about possible enhancements for J-Pilot. Convert pdb's and pc3's to SQLite. This makes it easier to analyze data according some criteria, e.g., find how many addresses have the same telephone numbers, how many entries in datebook contain the same substring, etc. Convert and…

Dead Keys and Compose Key

24th February 2013

My mother uses Xubuntu, i.e., she uses Xfce. She uses a German keyboard, but wants to write e-mails with spanish accents, i.e., she needs dead keys. At first I tried to solve the problem with a change in xorg.conf, which did not work. Some Google search revealed that a couple of people had the same…

jpilot-dump + jpilot-merge

17th February 2013

There is a lesser known command, jpilot-dump, to print portions of J-Pilot files. Here is an example to print category, first name, last name: jpilot-dump -A +A"%C %f %l" | less And here is another command: jpilot-merge.

ext3 vs. ext4

12th February 2013

Recently I installed an additional SATA drive on my Lenovo laptop. Without much ado I formatted the drive to ext4. Unfortunately, I quickly realized that the hard drive is spinning almost twice a second. My first drive on the laptop is also formatted with ext4, so using ext4 was a natural choice. A…

inotify-tools: inotifywait

29th January 2013

I wanted to see what files and when J-Pilot accesses its pdb and pc3 files. In my case strace produces much more output than actually needed. But inotifywait shows what and when files are accessed. inotifywait -m .jpilot/ inotifywait is in Debian/Ubuntu package inotify-tools. Here is an example of…

OpenGL Program: Earth with Moon Rotating around Sun

11th January 2013

My other son had a practical training at Fraunhofer IGD. He wrote an OpenGL/C++ program in Windows where one views the earth rotating around the sun, thereby with its rotating moon, see picture below. openglSunEM-X I ported this program to Gtk/Linux. You'll find the code in openglSunEM.c. The link…

On Differential Forms

10th January 2013

A couple of years ago I went through Otto Forster's Analysis 3 book for self study of differential forms. I thought the presentation could be leaned more towards matrices and determinants, which since Bourbaki's time got a difficult stand in mathematics. Here is the document: On Differential…

Dean Kamen at Bates College Commencement 2007

9th January 2013

Very inspirational and motivating speech held by Dean Kamen:

Computer Cooling

8th January 2013

Since using Alpenfoehn Gotthard CPU cooling has improved and the whole PC is more silent. On an otherwise idle PC, just xterm and Chrome running: $ modprobe it87 $ iostat avg-cpu: %user %nice %system %iowait %steal %idle 1.25 0.00 0.25 0.17 0.00 98.33 . . . $…

Number of Combinations for German Tax Id

7th January 2013

I was asked by a colleague of mine how many combinations are possible for the German tax id. The German tax id is built entirely from eleven digits. Its specification is given in Pruefziffernberechnung, see Steueridentifikationsnummer in the German Wikipedia. Every person reported to live in…

Infrastructure Costs for WordPress

6th January 2013

According the Bloomberg interview as of March 28, 2011, with Matt Mullenweg,, it costs 300-400.000$ per month to maintain 1.300 servers operating WordPress.

CPU Usage Time Is Dependant on Load

29th December 2012

I wanted to write a short benchmark for my son to demonstrate that the AMD Bulldozer 8 core CPU is better than a 6 core CPU from AMD when computing with integers. So I wrote a short C program to compute a recurrence relation using integers only, see C code below. When I ran this program on one…

Erster Eindruck von WordPress

2nd January 2008

Mein erster Eindruck von WordPress ist sehr gut. Die Schrift ist angenehm groƟ, die Bedienung einfach.

Hello world!

2nd January 2008

Welcome to This is your first post. Edit or delete it and start blogging!