Directory services is one of the most interesting and crucial parts of computing today. They provide our account management, basic authentication, address books and a back-end repository for the configuration of many other important applications. more>>

In this article, I'm diving into chemistry again. Many packages, both commercial and open source, are available to make chemistry calculations at the quantum level. The one I cover here is gromacs (http://www.gromacs.org). It should be available for your distribution via its package manager. more>>

A few weeks back, I was whining that although Doctor Who was available on Amazon Prime streaming, I didn't have any way to watch it on my television. Thankfully, my friend Richard Servello pointed me to the bluecop repo for XBMC. Not only does bluecop support Amazon Prime streaming, but it also has add-ons for Hulu and countless other network-video-streaming collections. more>>

Bitcoin mining is so last year. Put your expensive GPU to use cracking passwords.

When the Bitcoin mining craze hit its peak, I felt the tug to join this new community and make some easy money. I wasn't drawn only by the money; the concepts behind Bitcoin mining intrigued me, in particular the new use of graphics processors (GPUs). With a moderately expensive video card, you could bring in enough money to pay off your initial investment and your electricity bill in a relatively short time. more>>

Catalyst is the latest in the evolution of open-source Web development frameworks. Written in modern Perl and inspired by many of the projects that came before it, including Ruby on Rails, Catalyst is elegant, powerful and refined. It's a great choice for creating any Web-based application from the simple to the very complex. more>>

Most people have heard of gold. Most people are familiar with dollars. For a handful of geeky folks, however, the currency they hope will become a global standard is digital. Whether it's a problem or not, the currency you use on a day-to-day basis is tied to the government. more>>

HTML5 lets you play music through compliant browsers-no "cloud" required. more>>

Rubies, Pythons and Perls!

It may sound like a new Indiana Jones movie or possibly a cheesy platform-style video game from the 1990s, but the title of this column actually refers to our focus this month-programming! Not that there's anything wrong with daring adventures in remote locations, it's just that all the red tape can be overwhelming. more>>

Multiprocessing, multithreading and evented I/O: the trade-offs in Web servers.

A Web server needs to support concurrency. The server should service clients in a timely, fair manner to ensure that no client starves because some other client causes the server to hang. Multiprocessing and multithreading, and hybrids of these, are traditional ways to achieve concurrency. Node.js represents another way, one based on system libraries for asynchronous I/O, such as epoll (Linux) and kqueue (FreeBSD). To highlight the trade-offs among the approaches, I have three echo servers written in close-to-the-metal C: a forking_server, a threading_server and a polling_server. more>>

Sometimes events and equipment conspire against you and your team to cause a problem. Occasionally, however, it's lack of understanding or foresight that can turn around and bite you. Unfortunately, this is a tale of where we failed to spot all the possible things that might go wrong. more>>

A short while ago, an article appeared in Linux Journal implying Git was the be-all and end-all of source code revision control systems ("Git-Revision Control Perfected" by Henry Van Styn, August 2011). more>>

New products for April.

In my past several articles, I've looked at various packages to do all kinds of science. Sometimes, however, there just isn't a tool to solve a particular problem. That's the great thing about science. There is always something new to discover and study. But, this means it's up to you to develop the software tools you need to do your analysis. more>>

Poorly implemented monitoring systems can drive an administrator crazy. At best, they are distracting. At worst, they'll keep whoever is on pager duty up for nights at a time. This article discusses the best practices for designing systems that will keep your systems up and stay quiet when nothing is wrong. more>>

The first ever Blue Drop Awards for excellence in Drupal development were announced yesterday. Organized and led by Ben Finklea of Volacci, the awards were both a community effort to celebrate the great work of Drupal Developers, and also a vehicle for Drupal and open source evangelism. more>>