, 2 min read
How fast can you wipe a complete disk? For this I dumped zeros to a MS Windows partition based on an SSD formatted with NTFS. [root@i7 ~]# time dd if=/dev/zero of=/dev/sda1 bs=1M dd: error writing '/dev/sda1': No space left on device 81920+0 records in 81919+0 records out 85898297344 bytes (86 GB,…
, 1 min read
In various forums one reads that one should use dd to copy a ISO image to an USB stick. Although this works, more often you do not want to use a ISO image but rather copy a Linux system at hand. First you mount the root filesystem of the new USB stick, then mount /boot within a chroot. Finally use…
, 2 min read
Hearing all these wonder stories about btrfs I decided to give btrfs a try. Additionally I encrypted my SSD using LUKS. The relevant entries in the Arch WIKI are: Setting up LUKS and btrfs. Here is the list of commands I used. 1. I saved my data from SSD using tar and saved tar-file on…
, 1 min read
Just upgraded PulseAudio from 9.0-1 => 10.0-2, which was no good, as I was left with no sound. The bash script downgrade.sh given in Github by Gordian Edenhofer saved the day. Sound is back. The script is for Arch Linux. Usage: downgrade.sh libpulse pulseaudio pulseaudio-bluetooth From now on I…
, 1 min read
A very fine introduction by Prof. Dr. Victoria Kaspi to neutron stars, pulsars, magnetars, binary pulsars. Explaining their use in test for general relativity, and detection of gravitational waves. She also mentions Einstein@Home. Homepage of Prof. Kaspi is here. A recent (6-Jan-2017) observation…
, 1 min read
On 16-Dec-2016 my father died after a long and suffering disease. Born on 28-Nov-1934, he witnessed World-War-II, 1939-1945, separation of Germany, Suez Crisis, 1956, Cuban Missile Crisis, 1962, Vietnam War, Chinese Cultural Revolution, 1966-1976, but also the German reunification, and the Euro. As…
, 1 min read
Cablesurf is a German internet-cable-provider. They deliver Technicolor modem and set-top boxes to the end customers. My cable modem model is: HW Revision 1.0 VENDOR Technicolor BOOT Revision 2.4.0 SW Revision STDD.01.05 MODEL TC7200.20 …
, 1 min read
I wrote on SLURM used on Ubuntu here. As I moved to Arch Linux I of course use the fine AUR package slurm-llnl maintained by Gordian Edenhofer. After upgrading to version 16.05.7-1 I noticed the following: If slurmd is started by systemd then the pid-file specified for systemd in…
, 1 min read
I have written on the merits of 64-bit vs 32-bit, or on the AMD Bulldozer CPU Architecture Overview. An article in ithare.com gave a very good overview about the relative performance of various CPU operations. Below is the graphic: The above image is from IT Hare on Soft.ware. Also see the often…
, 1 min read
This blog was viewed more than 40.000 times and had more than 30.000 visitors. As in this post, here are the numbers: All these increases by 10.000 views all come roughly every eight months, see 30.000 (Jan-2016), 20.000 (Apr-2015), 10.000 (Sep-2014). So I kind of have reached a steady-state. The…
, 2 min read
There is a big difference between noise-cancelling headphones, and classical headphones without noise-cancelling ability! Especially when you use them in a noisy environment, like a plane or a large office bureau. Inspired by a positive review of the Bose headphones by Marques Brownlee, I bought…
, 4 min read
The mailing list for pacman-dev contains an interesting thread when rebuilding packages from source, i.e., running bacman in parallel. Gordian Edenhofer ran some tests on performance when running one, two, three, up to six jobs in parallel. The results, below, clearly show that using all your cores…
, 1 min read
Here is a photo when the Dell XPS-13 is opened: And here is the Acer Aspire opened:
, 8 min read
Very interesting. -- -- -- Quote -- -- -- Why does deep and cheap learning work so well Lin & Tegmark 2016 Deep learning works remarkably well, and has helped dramatically improve the state-of-the-art in areas ranging from speech recognition, translation, and visual object recognition to…
, 1 min read
If you start IceWM from GNOME, you can set your language settings in ~/.icewm/startup For example #!/bin/sh setxkbmap de Setting all available window-managers is done in /usr/share/xsessions Example: For starting icewm you can use the following configuration file…
, 1 min read
LibreOffice Impress version 5.1 and 5.2 for Linux kernel 4.7 becomes extremely slow, if one copies some slides multiple times. This behaviour can be reproduced on laptops, machines with and without graphic card. For example, take a random presentation and copy one slide 20 times by pressing ctrl-v.…
, 1 min read
In Hard-Disk and SSD Speed Comparisons I compared a Mushkin SSD with 60 GB against a ADATA with 128 GB against a Seagate 1 TB hard disk drive. The SSD's had roughly three times the speed of the hard disk drive. I.e., 380 MB/s vs. 134 MB/s for reading Mushkin vs. Seagate, and 297 MB/s vs. 131 MB/s…
, 2 min read
At times WordPress.com uses its user base to experiment with some half baked new features, see for example Classical editor in WordPress.com, or see this Hello Jekyll, bye Wordpress.com! These are the times when I consider migrating from WordPress.com to another blogging platform. Usually after…
, 2 min read
This post is about the Microsoft Exchange GAL, i.e., the global address list. The task is to export the data in the GAL to vCard format. Microsoft Outlook stores local caches of the GAL in %userprofile%\Local Settings\Application Data\Microsoft\Outlook, see Administering the offline address book in…
, 1 min read
In Effect of Optimizer in gcc on Intel/AMD and Power8 I measured speed ratios between optimized and non-optimized C code of three on Intel/AMD, and eight on Power8 (PowerPC) for integer calculations. For floating-point calculations the factors were two and three, respectively. Michael Larabel in…