My Blog Statistics by Country

26th September 2013

Except notably Russia and Africa this blog has been visited by quite a number of countries. I am surprised. Also see Statistics of this Blog: Top Views by Country.

dotScale 2013 MySQL Talk

23rd September 2013

Very interesting talk on the scaling challenge at given by Barry Abrahamson, CTO of WordPress. Some key points: 500 million database tables 3 data centers in USA 400.000 shards moved per day storage on SSD ~10% of total infrastructure costs are related to backups ~500 GB / shard 50…

WordPress/Automattic: Monthly Unique Visits and Employees

22nd September 2013

Below table is from work-with-us (data as of 22-Sep-2013): One of these things is not like the other. Company NameMonthly Uniques…

Georg Hager's Blog: Intel vs. GCC for the OpenMP vector triad: Barrier shootout!

21st September 2013

Georg Hager's Blog posted an illustrative article on icc versus g++ performance w.r.t. OpenMP. Dr. Georg Hager is one of the authors of Introduction to High Performance Computing for Scientists and Engineers. Measurement of double precision, dimension(N) :: a,b,c,d ! initialization etc. omitted s =…

Graphs with JpGraph by Asial

18th September 2013

JpGraph is a library of PHP code to draw a variety of graphs: line+bar+pie charts radar+polar+contour graphs bar+QR codes Gantt charts a couple of other chart types Here are two examples: JpGraph is a free product by Asial if used in a non-commercial context. Installation is quite easy on Ubuntu…

Line Integral of a Vector Field

16th September 2013

Inspired by a discussion with my son regarding movement of a point-charge between two other charges I revisited the definition of the line integral. Wikipedia offers an excellent visualization of the definition of the line integral for a vector field. See animated graphic below: This is something…

Torricelli's Trumpet: Infinite Surface Area but Finite Volume

13th September 2013

Just read on Torricelli's trumpet in Wikipedia. This states that there is a body having infinite surface but finite volume! That sounds contradictory at first. Function in question is $$ y = 1 / x $$ from \(x=1\) to \(a\). Volume is $$ V = \pi \int_1^a \left({1\over x^2}\right)\,dx =…

The Attraction of Curves – Brian Koberlein

13th September 2013

Brian Koberlein wrote a very good introductory article on curvature of space and time in the vicinity of gravity: see The Attraction of Curves – Brian Koberlein.

Dramatic Faster Sorting in Linux Using Nsort

12th September 2013

Last year I used a drop-in replacement for the ordinary Linux sort command called nsort from Ordinal Technology. Ordinal's nsort is free but not open-source. One thing is clear, however, it is very fast. nsort was written by Chris Nyberg. The motivation for looking for a faster sort was as follows.…

Harddisk Drive Speed in MB/s

11th September 2013

Below picture is from Read Throughput Average in Tom's Hardware.

Proportion of Papers on

9th September 2013 contains links to reviews, tutorials, research papers, program packages concerning various aspects of graphics and non-graphics (general purpose computing) using of GPU and related parallel architectures (FPGA, Cell processors etc.). The majority is on NVidia, see picture below.

India is now the third largest Smartphone market in the world - Android Authority

8th September 2013

An article in Android Authority from 26-Jun-2013, India is now the third largest Smartphone market in the world, states that: There are 14 major carriers listed for India, including two state owned providers. None have over 180 million subscribers. The smartphone market in India is expanding at…

Inhibit Annoying Message of the Day in Ubuntu

8th September 2013

I find the motd annoying when you log in to a Ubuntu server machine. To get rid of this I do the following as root: cd /etc/update-motd.d mkdir klmDisabled mv ??-* klmDisabled Unfortunately, whenever the packages update-manager-core, landscape-common, base-files, update-notifier-common change,… News and Numbers: The August 2013 Hot List

7th September 2013

As already posted last month, there are around 4 billion pageviews per month. This makes 1.4 pageviews per millisecond on the average. Each pageview incurs hundred of lines of PHP code executed, a couple of MySQL queries and updates.

China Built 600 Dams per Year Since 1950

6th September 2013

According Los Angeles Times (dead link) China built 600 dams per year on average. This trend will continue. According Wikipedia, or Jie Cai's Master Thesis (dead link), China has the largest potential for hydropower in the world and currently ranks first in hydroelectric generating capacity with…

Newer GPUGRID Tasks Keep GPU Really Hot

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…

Using WordPress for 5 Years Now

31st August 2013

Saving URLs in Still Troublesome

31st August 2013

I have been using (dead link) since at least the year 2005. During that time (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…

Mark Twain Commentary on the MacBook Air

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…

Copy Directories with Symbolic Links via ssh

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…

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