Did you know that the performance of an if-statement depends on whether its condition has a predictable pattern? If the condition is always true or always false, the branch prediction logic in the processor will pick up the pattern. On the other hand, if the pattern is unpredictable, the if-statement will be much more expensive. In this article, I’ll explain why today’s processors behave this way.
This blog exists purely as a place for me to dump random links and thoughts I have rather than emailing them to my friends. It'll have large amounts of inside jokes. Also there will probably be times when I write "you" or refer to an email. Just pretend that you are reading an email to you. If you don't know me you likely won't find anything here interesting. If you do know me you also will not find anything here interesting.
Monday, January 31, 2011
Fast and slow if-statements: branch prediction in modern processors
http://igoro.com/archive/fast-and-slow-if-statements-branch-prediction-in-modern-processors/
EURion constellation
https://secure.wikimedia.org/wikipedia/en/wiki/EURion_constellation
The EURion constellation is a pattern of symbols found on a number of banknote designs worldwide since about 1996. It is added to help software detect the presence of a banknote in a digital image. Such software can then block the user from reproducing banknotes to prevent counterfeiting using colour photocopiers.
Sunday, January 30, 2011
Julian Assange On 60 Minutes
Julian Assange did a 30 minute interview on 60 Minutes. In case you aren't currently in a retirement home, it's online here:
http://www.cbsnews.com/video/watch/?id=7300034n - Part 1
http://www.cbsnews.com/video/watch/?id=7300036n - Part 2
http://www.cbsnews.com/video/watch/?id=7300034n - Part 1
http://www.cbsnews.com/video/watch/?id=7300036n - Part 2
The crescent and the company
http://www.economist.com/node/18008627?story_id=18008627
For most of its history the Middle East was just as dynamic as Europe. The great bazaars of Baghdad and Istanbul were full of fortune-seekers from hither and yon. Muslim merchants carried their faith to the far corners of the world. In the 1770s Edward Gibbon had little difficulty imagining Islamic theology being taught in Oxford and across Britain—if only the battle of Tours-Poitiers in 732 had turned out differently.
But even before Gibbon the balance of power had shifted. Angus Maddison has calculated that in the year 1000 the Middle East’s share of the world’s gross domestic product was larger than Europe’s—10% compared with 9%. By 1700 the Middle East’s share had fallen to just 2% and Europe’s had risen to 22%.
Saturday, January 29, 2011
Thursday, January 27, 2011
The Apollo Astronauts' Fascinating Insurance Covers
http://www.ukinsurancenet.com/blog/index.asp?post=apollo-insurance
http://www.collectspace.com/ubb/Forum20/HTML/000118.html
http://www.collectspace.com/ubb/Forum20/HTML/000118.html
It's incredible to think that astronauts once needed to improvise in such a way, but these fascinating images show the lengths to which some crew of the Apollo program had to go in the name of life insurance. As we all know, the job of an astronaut is inherently filled with risk, and as such - particularly in the early days of the Apollo program - an astronaut's mission into space was literally uninsurable. Of course this situation didn't sit well with the astronauts, many of whom had families and other dependants to support should their space flight unfortunately end in death.
Tuesday, January 25, 2011
Monday, January 24, 2011
Eavesdropping Laws Mean That Turning On an Audio Recorder Could Send You to Prison
http://www.nytimes.com/2011/01/23/us/23cnceavesdropping.html
Ms. Moore, whose trial is scheduled for Feb. 7 in Cook County Criminal Court, is accused of using her Blackberry to record two Internal Affairs investigators who spoke to her inside Police Headquarters while she filed a sexual harassment complaint last August against another police officer. Mr. Drew was charged with using a digital recorder to capture his Dec. 2, 2009, arrest for selling art without a permit on North State Street in the Loop. Mr. Drew said his trial date was April 4.
Although law-enforcement officials can legally record civilians in private or public, audio-recording a law-enforcement officer, state’s attorney, assistant state’s attorney, attorney general, assistant attorney general or judge in the performance of his or her duties is a Class 1 felony, punishable by up to 15 years in prison.
Sunday, January 23, 2011
Why Bad Guys Matter
http://www.foreignpolicy.com/articles/2010/06/21/why_bad_guys_matter
Leaders matter, for better or, more likely, for worse. Sure, some of Asia's "benign" autocrats have turned their ambitions to building strong national economies. But not in Africa and many of the other countries that I call the bottom billion -- quite a number of which crowd the upper reaches of the Failed States Index. There, the most common form of autocracy is anything but benign. These leaders not only neglect to build the economy, they actively avoid doing so. The best-known instance is President Mobutu Sese Seko's order to "build no roads" in the vast country then known as Zaire. Why? Because without roads, it was harder for opponents to organize a rebellion against him.
Saturday, January 22, 2011
Thursday, January 20, 2011
Tuesday, January 18, 2011
Monday, January 17, 2011
For why so few girls major in computer science in college, below is my answer.
http://news.ycombinator.com/item?id=2111651
So, a typical scenario is a boy in middle school who is really excited because he just understood how an automobile differential (TCP part of TCP/IP, binary search, virtual memory, etc.) works and with great excitement tries to explain it to a girl his age at, say, lunch, and we have a strict dichotomy: The boy is totally clueless that the girl couldn't be less interested. The girl sees right away that she couldn't be less interested, not to offend the boy unduly pretends to be a little interested, and sees in clear terms that the boy is totally clueless at perceiving her lack of interest. She concludes that he is so clueless he is really easy to manipulate (a fact she suspects could be useful and saves for later). The boy doesn't understand the girl, and the girl regards the boy, and soon, all boys less then 2-6 years older than she, as at least 'socially' immature and, really, just immature. She wants nothing to do with such 'children' (she already understands that a woman needs a strong man) and will concentrate on boys 2-6, maybe 8 or 10, years older than she is. She has a point: She was likely more mature socially at age six than he will be at age 16.
Wednesday, January 12, 2011
The Antibiotics Crisis
http://www.huffingtonpost.com/dan-rather/the-antibiotics-crisis_b_807887.html
Every year, more than ninety thousand Americans die from similar infections that have become resistant to antibiotics. That stunning figure is higher than the death toll from AIDS, car accidents and prostate cancer combined.
Seven decades since the discovery of antibiotics, it's clear that science still cannot keep pace with bacteria. Dr. Stuart Levy, a professor of molecular biology at the Tufts School of Medicine and one of the world's leading medical authorities on antibiotics, says the cause of the crisis is not in dispute: we are simply using too many antibiotics.
Tuesday, January 11, 2011
Wednesday, January 5, 2011
Tuesday, January 4, 2011
Hipmunk: Flight Search
http://www.hipmunk.com/
Came across this site. It looks like an excellent flight search engine. It's unlikely I'll be required to fly anywhere for the foreseeable future, but perhaps others will find it useful.
Came across this site. It looks like an excellent flight search engine. It's unlikely I'll be required to fly anywhere for the foreseeable future, but perhaps others will find it useful.