, 2 min read
I found a marvelous way to run jobs on certain business days via cron. The solution was depicted in Scheduling Cron Jobs on Business Days and it was written by a user named rdcwayx. The idea is to use the output of cal and some Awk or Perl string-trickery. The output of cal looks like this …
, 2 min read
Cisco provides a report on computer security which contains a number of key findings: Java comprises 91% of all web exploits. 99% of mobile malware targets Android. Java is the exploit that criminals choose first, since it delivers the best return on investment. In the aftermath of the [Boston…
, 2 min read
Today I noticed the following error on Youtube, which seems to be quite rare. Maybe some trained monkey comes by and can make use of below gibberish. 500 Internal Server Error Sorry, something went wrong. A team of highly trained monkeys has been dispatched to deal with this situation. If you see…
, 1 min read
Unfortunately Google gets quite draconian to users: When using Google Chrome to surf a web page with a certificate problem, you simply cannot view the website. There is no dialog, where you can say: It's o.k., I accept the risk. This behaviour occurs at least with versions 31.0.1650.63 and…
, 2 min read
Sometimes you have to create applications in an environment where you are not able to su to root, or use sudo. Nevertheless you are working with two or more user IDs to make your application work. For example, your business application is running under user ID 1555 (let's call this user u1555),…
, 2 min read
In continuation of Working with System V IPC queues a month ago this post will show how to access IPC queues with Perl and PHP. A typical scenario is that a web application wants an external application to process data coming from the web application. In that scenario a lot of messages/tasks from…
, 2 min read
I own a desktop PC with an AMD octacore FX 8120 and a NVidia GTX 560 graphic card running GPUGrid. What is the power consumption in Watts over time? I ran ( while true; do powerconsum ; sleep 2; done ) & with below script powerconsum reading data from sensors: #!/usr/bin/perl -W use…
, 3 min read
A couple of times I had to conduct effort estimations which contained a number of repetitive tasks. The question was, how long does it take to finish all these tasks. For example, I had to provide estimates how many days it would cost to program an interface between one system interfacing to a…
, 2 min read
Android application programs are usually written in the Java programming language. Java source code is compiled to bytecode, which is then interpreted by the Java virtual machine. Current virtual machines (VM for short) use two tricks to improve performance: compile bytecode to machine code during…
, 1 min read
I was just asked this question and referred to Phoronix: Ubuntu 12.04 LTS: 32-bit vs. 64-bit Performance. Phoronix is this excellent website run by Michael Larabel. Below is a chart from 2012. Not all charts look this astonishing! This was also true in 2006, see below compilation times. So the…
, 3 min read
Occasionally I teach customers and colleagues how to use some aspects of Linux, or how to use and administrate newly developed software on Linux. I regularly use either VNC or kibitz for this. While VNC is somewhat known to many people, kibitz seems to be like a hidden germ, unbeknownst to…
, 1 min read
Some facts on Wikipedia: Wikipedia uses round about 1,200 servers, see Tactical Monitoring Overview. These servers are located in Ashburn (Virginia), Tampa (Florida), San Francisco, and Amsterdam, see servers. Wikipedia has about 4.5 million pages, see statistics. Wikipedia uses Ubuntu exclusively…
, 2 min read
This week I upgraded again, this time from 50 MBit/s to 100 MBit/s. My internet service provider is Unitymedia with whom I had positive experience since 2009, see Unitymedia experience. They phoned me mid of November and asked whether I would be interested in upgrading from 50 to 100, it would cost…
, 1 min read
Great article about Einstein@Home by Brian Koberlein: Astronomy at Home – Brian Koberlein. This is interesting in particular: The team used the distributed computing network to analyze x-ray data from the Fermi gamma ray telescope. From this they found four new gamma ray pulsars. Most gamma ray…
, 3 min read
This article "CUDA-Enabled GPUs" made me check my GPU again using deviceQuery in /usr/local/cuda/samples/sdk/1_Utilities/deviceQuery: CUDA Device Query (Runtime API) version (CUDART static linking) Detected 1 CUDA Capable device(s) Device 0: "GeForce GTX 560" CUDA Driver…
, 4 min read
There are a variety of ways to work with queues: You can purchase IBM WebSphere MQ (formerly known as MQSeries), or similar products from Oracle or Microsoft. On most Unix systems queues are already built in, as long as you do not need any functionality to cross machine boundaries, i.e., hop from…
, 1 min read
Comparing the academic industry with a rather disparate industry, thereby highlighting a number of shortcomings of the current situation in academia. Also see Marcio von Muhlen: We Need a Github of Science, documenting the "Profzi"-scheme. Interesting article from Alexandre Alfonso on…
, 1 min read
Most IT people know about trojan horses, virus, worms, honeypots, etc. They know about buffer overruns, SQL injection and the like. What is probably not that well known is that even "friendships" on social networks can pose some risks: They give credibility to possibly complete fake…
, 15 min read
Malcolm Gladwell held a speech at Google Zeitgeist Americas 2013 about drop-out rates in schools, especially in math and science. It turns out that going to one of the top universities is rarely a good idea, contrary to popular belief. Some quotes: EICD - elite institution cognitive disorder Your…
, 1 min read
A recent article "Five Minutes with Alison Barrett" linked to a speech by Alison Barrett on Unit Testing in particular in PHP. The speech almost in passing made a reference to a famous quote on "good fast cheap, pick two", which I found quite noteworthy. Using Google I found a…