6th September 2013
Recent GPUGRID tasks, like I60R2-NATHAN_KIDKIXc22 or 27x0-SANTI_RAP74wtCUBIC really keep my NVidia GTX 560 hot, i.e., as warm as 70° Celsius or higher. Fri Sep 6 17:16:38 2013 +------------------------------------------------------+ | NVIDIA-SMI 5.325.15 Driver…
31st August 2013
31st August 2013
I have been using del.icio.us (dead link) since at least the year 2005. During that time del.icio.us (dead link) was sold to Yahoo, which didn't do very much with this bookmarking service. It simply worked. In 2011 the service was acquired by a company named AVOS (dead link), see Wikipedia for the…
31st August 2013
Mark Twain's (1835-1910) words still relevant today for people who want to change established things hastily. From Ken Krugler on Mark Twain Commentary on the MacBook Air: One of my favorite posts to the Unicode mailing list came during a heated debate about “simplifying” certain character…
25th August 2013
Although probably known in most circles, it is worth repeating that scp by itself does not honor symbolic links. To overcome this limitation just combine tar and ssh, i.e., tar on sending side, untar on receiving side: tar cf - /src/dir | ssh remotehost "cd /dst/dir ; tar xf -" Usually…
21st August 2013
Average Size of Web Pages plus Prediction shows an exponential fitting to web-page sizes. From above article: As you can see, the 1/2 MB mark was cracked in 2009 and the 1 MB mark was cracked in 2012. Despite the seemingly random fluctuations, an exponential trend is clearly visible. The power…
15th August 2013
A colleague of mine noticed some strange behaviours in his programs. It was later discovered that this is due to SyncSort not conducting a stable sort. Stable sort means that the sequence of elements in input is not changed if there is no strict need to change them. Unfortunately, the documentation…
13th August 2013
Some statistics from WordPress just for month July, 2013. These sheer numbers almost sound unbelievable: 1 million new blogs 7 Exabyte of data 1 billion pages accessed by mobile devices 9 million YouTube videos embedded 500.000 posts per e-mail 200 posts per voice
11th August 2013
For the numerical solution of the ordinary differential equation, initial value problem $$ y'=f(t,y), \quad y(t_0)=y_0,$$ one can use a cyclic composite multistep method of the form $$ \sum\limits_{i=0}^{m} A_i Y_{k+i} = h \sum\limits_{i=0}^{m} B_i Y'_{k+i}, \qquad…
4th August 2013
I got somewhat tired of using FTP with my Android, even with lftp. Keeping multiple folders in sync is simply very cumbersome. If I only had rsync working on Android! I found SSHelper, written by Paul Lutus, see also Arachnoid. SSHelper offers ssh, scp, rsync. You can ssh to your Android phone and…
4th August 2013
When visiting Harvard University I received an Emergency Alert directly on my phone, see below. Google Now Emergency Alert At first I thought that this was a kind of student hack, but others just received the same alerts. After inspection it contained additional information, shown below. Flood…
27th July 2013
Lawrence Livermore National Laboratory provides a suite of software packages for the solution of ordinary differential equations. This suite is called SUNDIALS. SUNDIALS consists of CVODE: solves initial value problems for ordinary differential equation (ODE) systems; successor of GEAR, EPISODE,…
24th July 2013
HipHop Virtual Machine says that HHVM can run WordPress. A more technical description of the HHVM can be found in Speeding up PHP-based development with HipHop VM. One of the main targets was to be as fast as the previous PHP to C++ translater. This goal has been achieved, see graph: Unfortunately…
19th July 2013
Gunnar Heinsohn (German Wikipedia, English Wikipedia) wrote a book with title Söhne und Weltmacht -- Terror im Aufstieg und Fall der Nationen in German. This book is about: youth bulge and its implication to criminal or war activity genocide property and possession This book can explain why…
30th June 2013
My recent project had some issues with hashing some 10 million numbers. To analyze the matter I wrote a small test program, see numberhash.c. I wanted to know which influence the following factors play: hashing just numbers (no alphabetic characters) ASCII vs. EBCIDC choice of hash function load…
30th June 2013
Here is a simple test program to call SHA1 hashing routine from OpenSSL. #include <stdio.h> #include <string.h> #include <openssl/sha.h> int main (int argc, char *argv[]) { unsigned long i, n; unsigned char md[1024]; if (argc <= 1) return 0; n…
29th June 2013
Peter Kankowski wrote a very interesting article on hashing functions. It compares a number of current hash functions and conducts some performance benchmarks. iSCSI CRC Meiyan Murmur2 XXHfast32 SBox (dead link: https://home.comcast.net/~bretm/hash/10.html) Larson XXHstrong32 Sedgewick Novak…
29th June 2013
Here is an article GNU C: Extensions to the C Language Family about extensions in GNU C vs. ANSI C. Nested functions, i.e., a function defined within another function Double-word integers, i.e., 64 bit signed and unsigned long long int and unsigned long long int Arrays of variable length, f(int z)…
22nd June 2013
Recently I learned the hard way that IBM Enterprise COBOL compiler for z/OS (mainframe) cannot generate 8-byte long POINTER variables, but only 4-byte pointers. This means, you cannot use more than 2GB in COBOL on a mainframe. I.e., you cannot make use of AMODE=64 with COBOL on the mainframe. You…
21st June 2013
Generators (and therefore coroutines) are now part of PHP (Wikipedia) 5.5, as of 20-Jun-2013. Here is an example: function xrange($start,$end) { for ($i = $start; $i<=$end; ++$i) yield($i); } The Icon programming language (Wikipeda) was one of the first computer languages where…