Geek Tips

Saturday, September 13, 2008

Optimization

Optimization is about finding bottlenecks and then using the scientific method.

The typical bottlenecks are CPU, RAM, Disk, and Network. A little research will reveal the tools that give you insight into those subsystems on your platform.

Using those tools, you can identify which processes are stressing each subsystem. Then a little more research will reveal the tools that give you insight into that process.

Then a little-to-a-lot more research will reveal what you can do to reduce the stress or beef-up your platform.

After you do this for a bit, you’ll see why LAMP is usually referred to as a stack, and not as a turn-key server. Different parts of the stack need to be optimized for different subsystems.

Another very useful bit of research would be finding or writing your own tools to stress each of the subsystems.

Found in a comment on Slashdot, by foo fighter

Thursday, June 26, 2008

La mort du papier?

Un nouveau support de lecture électronique devrait voir le jour en 2009 selon la société productrice, E-Ink.

Un nouveau support de lecture électronique devrait voir le jour en 2009 selon la société productrice, E-Ink.
De l’encre électronique

Nommé E-Paper il utilise une technologie E-Ink à base d’encre électronique. Son principe de fonctionnement chimique lui garantit une épaisseur de 80 micromètres ainsi qu’une flexibilité digne du papier traditionnel. En outre, l’encre électronique ne produit aucune lumière pour assurer une lisibilité exemplaire et ne consomme pas d’énergie lors des changements de page.
Le Monde intéressé par le E-Paper

Éradiquant l’utilisation du papier, le E-Paper devrait passer en phase de test à la fin de l’année. La première utilisation commerciale de ce support sera destinée à la distribution de quelques quotidiens japonais au printemps 2009 si les essais de la société E-Ink sont concluants. Par ailleurs, on notera que certaines autres publications américaines et européennes. Ainsi, Le Monde serait en train d’envisager une éventuelle publication de ses contenus sur ce format. Écologique puisque sans papier, le E-Paper devrait aider à la diminution de la déforestation.

Thursday, June 19, 2008

Internet connected coffee maker leaves your PC, mornings at risk

It looks like those that enjoy a little remote control over their coffee could be unwittingly leaving both their PCs and their precious brew vulnerable, at least according to BDO risk advisory services manager Craig Wright, who found that his Jura F90 internet-connected coffee maker had several significant security holes, including a buffer overflow in its internet connection software. That, he says, could potentially allow an attacker to take control of the PC connected to the coffee maker, not to mention control the strength of the coffee and perform unwanted diagnostics. Of course, given the number of internet-connected coffee makers out there right now, Wright admits that the potential risk is relatively low (and moot if it’s behind a firewall), but he has some dire warnings for the future, saying that eventually “you’ll be able to turn on your oven with your mobile phone,” which he says could lead to a malicious hacker “burning the house down.”

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Sunday, June 15, 2008

Sphinx Engine: An amazing open-source SQL full-text search engine

Sphinx is a full-text search engine, distributed under GPL version 2. Commercial license is also available for embedded use.

Generally, it’s a standalone search engine, meant to provide fast, size-efficient and relevant fulltext search functions to other applications. Sphinx was specially designed to integrate well with SQL databases and scripting languages. Currently built-in data sources support fetching data either via direct connection to MySQL or PostgreSQL, or using XML pipe mechanism (a pipe to indexer in special XML-based format which Sphinx recognizes).

As for the name, Sphinx is an acronym which is officially decoded as SQL Phrase Index. Yes, I know about CMU’s Sphinx project.

Sphinx Engine

Saturday, June 07, 2008

Lib iconv : how to manage the differents encoded characters

Lib iconv

For historical reasons, international text is often encoded using a language or country dependent character encoding. With the advent of the internet and the frequent exchange of text across countries - even the viewing of a web page from a foreign country is a “text exchange” in this context -, conversions between these encodings have become important. They have also become a problem, because many characters which are present in one encoding are absent in many other encodings. To solve this mess, the Unicode encoding has been created. It is a super-encoding of all others and is therefore the default encoding for new text formats like XML.

Still, many computers still operate in locale with a traditional (limited) character encoding. Some programs, like mailers and web browsers, must be able to convert between a given text encoding and the user’s encoding. Other programs internally store strings in Unicode, to facilitate internal processing, and need to convert between internal string representation (Unicode) and external string representation (a traditional encoding) when they are doing I/O. GNU libiconv is a conversion library for both kinds of applications.