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Compare linux-3.8.4: Compile times. This time we compiled Linux kernel 3.9 and used time make -j 20 according Compiler Speed-up. My 8-core machine is fully loaded, as can be seen by top: top - 21:08:50 up 30 min, 10 users, load average: <strong>21.92</strong>, 16.95, 8.40 Tasks: 257…
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Article on Max Planck Institute Millenium Simulation. Pictures of the galaxy distribution Addendum: There is an article on the Millenium Simulation in Brian Koberlein's article Sim Universe.
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Brian Koberlein on Google+ on Astronomy (dead link) contains a number of interesting articles on current developments in astronomy and relativity. Added 31-Aug-2013: Brian Koberlein now has a WordPress powered separate web presence: www.briankoberlein.com. Added 21-Oct-2013: Brian Koberlein noted…
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Very good article by Bruce Dawson on timing CPU bound application. Results are: Using $(expr) to do math is over a hundred times slower than using bash internals. This is not a new discovery, but it’s worth reiterating. Excessive use of sub processes (see point 1) can confuse the Linux…
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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.…
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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.
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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.
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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…
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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…
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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…
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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…
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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.
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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…
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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…
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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…
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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…
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Very inspirational and motivating speech held by Dean Kamen:
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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 …
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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…