Category Archives: Spare Time

Early impressions of my RaspberryPi

Posted by Raphael on January 20th, 2013 Comments Off

Last year I ordered a RaspberryPi; I wanted to check out the hype and, who knew, maybe I’d get a decent media (or at least music) player out of it. The machine arrived right in time for Christmas, together with an SD card preinstalled with Raspbian and a USB power supply.

Wow, the CPU of this thing is slow. I was lucky to get the new version with 512MB RAM, I guess. Any CPU-heavy task feels extremely sluggish, be it aptitude, X or — beware! — watching videos. The GUI software package that comes with Raspbian is all but useless, too, so I soon decided to stick to a native terminal.

I was quite disappointed with the video performance which resembled a slide show; I had wanted to use the Pi as media center, after all. So I did some research and learned that there is apparently only one player which can harness the hardware video decoding capabilities the Pi has to offer: the OMXPlayer.

Turns out Raspbian with OMXPlayer does a better job of playing full HD videos than my gaming PC, and without the noise and barely any heat. Of course, you should not start X but run the player from shell (yes, that works!); not the most intuitive interface — and you have to change the terminal font if you use a big TV — but very efficient. Files are stored on an external HD connected to another PC which the Pi mounts via ssh. So far, I have not experienced any problems with this setup.

The only sore point has been the board layout; the connectors you can’t go without (Ethernet, USB, HDMI, AC) face three different directions, so the Pi is awkward to place if you want to run all cables to the back. Some minor annoyances are missing codecs, for example WMV, and a handful of inconveniences in OMXPlayer.

I have not yet tried using XMBC which is supposed to work well. Installing it on Raspbian does not seem to be straightforward; maybe I’ll try out Raspbmc on another card. Does anybody have experience with that?

Richard L. Sanders: The Phoenix Conspiracy

Posted by Raphael on April 9th, 2012 Comments Off

Richard L. Sanders: The Phoeanix Conspiracy

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Calvin Cross is a successful and loyal officer in Intel Wing, the Empire’s intelligence organisation. He is so good that he has been given his own command, the stealth frigate Nighthawk, despite the fact that he is only a half-citizen and therefore stuck at a junior officer rank. His latest mission has been to track down rogue warship captain Raidan who used his position to destroy civilian alien freighters without provocation. Raidan is tried by a tribunal and found guilty, but his motives remain unknown. The prisoner escapes under suspicious circumstances—hijacking a dreadnought in the process—and Cross is again ordered to find him. Cross suspects foul play as several facts do not add up and decides to investigate the underlying situation rather than hunting down the fugitive. While he tries to keep up appearances his mysterious opponents act to stop Cross and his crew no matter what.

Phoenix Conspiracy has a solid, but not brilliant setup. The futuristic world is very similar to ours despite the fact that humanity travels across space; culture and technology appear unchanged for the most part. It works well enough for this kind of story as the reader feels comfortable from page one and can completely focus on the intriguing plot. The conspiracy is nicely set up and the characters are likeable yet complex enough to feel real, including heart-felt emotion and sometimes funny, sometimes nerve-wracking conflicts. Only the ending seemed a bit too hasty and shallow for my taste; but then, this is only part one of a series so I will give Sanders the benefit of doubt, assuming the rabbit hole is deeper than it seems. Phoenix Conspiracy managed to captivate me and I had a good time reading it. I certainly look forward to the sequels!

Get this great read in a variety of formats for free and DRM-free on Smashwords.

Adrian Hall: Feng Shui Assassin

Posted by Raphael on April 2nd, 2012 2 comments

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Harvey Barker is on a revenge trip in modern London, killing the people he holds responsible for his sister’s death. He is a professional assassin, but an unorthodox one: he kills using feng shui, manipulating chi and karma to kill his targets without anyone the wiser. But he is not careful enough this time. Detective Amanda Morgan can not shake the feeling that a couple of apparently tragic deaths are connected. Meanwhile, the remaining members of the group Harvey hunts down try to recover and strike back.

I needed to suspend a lot of disbelief regarding the manipulation of chi and karma. The concept seems confused at times, but experienced manga readers should have no problems accepting it. Hall’s prose is not perfect but good enough so it does not distract from his decent story. He builds a good amount of tension towards the end, finishing a very entertaining and thrilling book.

Get this good read in a variety of formats for free and DRM-free on Smashwords.

Brandon Sanderson: The Alloy of Law

Posted by Raphael on March 26th, 2012 Comments Off

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The Alloy of Law is set in the world of the Mistborn trilogy, about 300 years after the original books. The heroes of that time have become figures of myth and religion. The area around the pre-industrial capital (formerly Luthadel) is fertile and wealthy, farther out in the Roughs live is like in our Wild West. This is where noble-blooded lawkeeper Wax has made it his job to hunt down criminals until personal tragedy prompts his return to the city. He tries to blend in the noble society and behave as he should but is soon intrigued by a series of seemingly impossible thefts. Instead of preparing his inevitable engagement properly he starts to investigate, supported by his friend and colleague Wayne who has come to visit in order to make sure Wax does not die in of boredom.

Alloy of Law is fast, fun and tragic, but most of all fast. Allomantic-Feruchemic gunfights are probably the most awesome, cinematic thing I have read in a while. They show how incredibly well-conceived Sanderson’s magic system is: it evolves and scales with ease. The story itself is a diverting piece in Sherlock Holmes style, nothing too deep. There is potential for follow-up stories, though, so we’ll see. The main characters are very well-developed considering the size of the book; Sanderson makes every word count¹. Besides the abundance of action, verbal exchanges between Wax, Wayne and later Marasi provide most of the fun and make the book a light read despite several tragic scenes. As a fan of the series, I enjoyed the many (religious) references—fact distorted to myth by time—to the old heroes, in particular how their way of life evolved to outright schools of philosophy².

That I recommend a Sanderson book is probably no surprise, me being a devoted fan of his. Go and read this book even if you have not read or did not like³ the trilogy, it is fun!

This book is short by Sanderson’s standards! ↩
Personally, High Imperial cracked me up the most! ↩
The most frequent complaint seems to be that the trilogy is too slow-paced; this is certainly not the case for Alloy of Law! ↩

Computer Science Stack Exchange Live!

Posted by Raphael on March 25th, 2012 Comments Off

Computer Science Stack Exchange public beta

cs.SE in nondescript beta style

Since my post in December, Computer Science Stack Exchange has gone through private beta and is now accessible for everybody. Head over to cs.stackexchange.com and take a look! We are waiting for your questions so do not hesitate to post anything you have always wanted to know in computer science¹, be it theory, applied or even practical!

We also need more expertise: out off almost 190 questions sixteen have yet to receive a good answer. among those are one about equivalence of Büchi automata and linear μ-calculus and another about efficiently learning regular languages.

You might also want to check out our hottest questions, including why Quicksort is often considered the best sorting algorithm, encryption using NP-hard problems and connections between Gödel’s incompleteness theorem and the halting problem.

I am very excited about this site. One one hand, it gives me the opportunity to share my knowledge in computer science with a wide variety of people, and I like teaching. On the other hand, I get to learn a lot. Not only do people ask about things I know next to nothing about so I can learn from the answers, but there are also original concepts. My favorite is Patrick’s proposal of heap automata; I have spent several hours contemplating his question about their power and follow-up questions.

I hope to see you on cs.SE soon!