23 Sep 2011 dangermaus   » (Journeyer)

"Force has no place where there is need of skill." - Herodotus

Kahn's wisdom

Khan Academy published new exercices and this revived my interest in the platform: I solved some more exercices and watched through several videos. While watching "How Earth's tilt causes Seasons" I realised a conceptual mistake in simclimate (released with GPU): I consider the angle for sunlight but not day duration of sunlight... I also watched the series on Milancovitch Precession and Obliquity, Orbit Excentricity wobbling and Perihelion precession. I had the Python introduction, courses about Human Evolution and Earth Formation, and I then decided to start a complete refresh of Linear Algebra, as the course attended at university was taken 13 years ago. And even at work, from time to time, linear algebra is lurking. (Current status: exercices: 176/188, videos: 187/2259)

Journey in Hackerland

The quests are getting definitively more difficult to solve. This month I could solve only eight challenges. Revision 54 of my Brainfuck interpreter written in Superhack language finally conquered the fortified castle. For "Spiral bits" my prototypes aren't good enough yet, so that one complete area of Hackerland remains off range. "Execution Style" and several didactic cipher challenges were solved. Also the Lawsonomy secret is unveiled. But speaking of didactic cipher challenges: brute force works only up to 4 billion keys, which can be tested in roughly a quarter hour of computations assuming printable ASCII characters. If the key space is bigger, this quote is definitely not valid: "If force does not work, you are not using enough force". For "Branches" I painfully worked out a solution, but the number I get is not accepted as solution, meaning that probably I cut off too much code or that I oversimplified the recursion. Who knows. For "Snake Arithmetic", I understood how the nominator is composed, but I still could not telescope the denominator part of the Python equation. For "Anybody Out There" I bought the book "Fourier Transform for pedestrians", but I am still waiting for it as it is out of print and the new edition should come this month. For this alien challenge, I also asked help to an old keen friend of mine who studied physics.

Through my journey, I discovered plenty of tools worth of mention: IntelliJ IDEA, Netbeans and ImageMagick. My favourite pseudorandom generator ISAAC has a companion in form of the RadioGatun hash function.
(Current status: rank 212, quests 165/277)

deltasql 1.4.1

deltasql 1.4.1 is a maintenance release. I discovered a stability problem in deltaclient (for which a dedicated patch of 1.4.0 was done), and tried to minimize the impact of undefined index errors when using strict error_reporting in php.ini. Some unused columns were dropped and the synchronization INSERT statement was simplified. This release really qualifies for the maintenance tag.

My next goal is to try to develop a plugin for the Squirrel SQL client, which is phantastic client which is able to connect to multiple database types (as it is based among other drivers on JDBC ones, a technology I am familiar with). Squirrel SQL is useful at work as well, as there I do not have administrator rights, and I am therefore prevented to install the full Oracle driver.

Linux Magazines

I am a fan of Linux Magazine. I read many articles there, including one presenting System Dynamics tools used in simulations and one about the Hercules Mainframe emulator. And all the cloud computing stuff is more than a hype. Virtualbox is definitely running on my computers. Plenty of images for Virtualbox are here.


I downloaded Wikileaks cables from Cryptome. For the moment, I decided to split them with split -b 4096k cables.csv cableparts and to search through them with fgrep -i tanzania cableparts* > tanzania.txt. Probably not the best approach, though.

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