Tutorials

Spinlocks are the lowest-level mutual exclusion mechanism in the Linux kernel. As such, they have a great deal of influence over the safety and performance of the kernel, so it is not surprising that a great deal of optimization effort has gone into the various (architecture-specific) spinlock implementations. That does not mean that all of the work has been done, though; a patch merged for 2.6.25 shows that there is always more which can be done.

They are four applications designed to serve different purposes: A web browser, a music player and organizer, another that does the same for video, and a word processor for screenwriters. Yet they share one thing in common: All were built with a Mozilla-based toolkit, either the Gecko Runtime Environment or its successor, XULRunner. Both toolkits use the same codebase which runs Firefox.

One of the fundamental principles of Linux kernel development is that user-space interfaces are set in stone. Once an API has been made available to user space, it must, for all practical purposes, be supported (without breaking applications) indefinitely. There have been times when this rule has been broken, but, even in the areas known for trouble (sysfs, for example), the number of times that the user-space API has been broken has remained relatively small.

Memory defragmentation is a subject which has appeared often in kernel discussions - even if no solutions have yet found their way into the mainline kernel. Most of the defragmentation approaches out there work at the page level with the idea of being able to satisfy multi-page allocations reliably. There is another type of fragmentation problem, however, which also has the ability to complicate the kernel's memory management: fragmentation within slab pages.

So, you've just installed Ubuntu 7.04, otherwise known as the "Feisty Fawn" release of everyone's favorite (for now) flavor of Linux. You booted the installation disc , looked around the test environment to discover that your hardware was working, and double-clicked the Install icon on the desktop. The Ubuntu installer helped you make room for Linux on your hard drive, and even copied over some of your documents and settings from Windows.

Planning a migration from Windows PCs to Linux-based desktops is no small task. Here are six issues and strategies to consider before getting started.

A couple months back, I was at home, working on some changes to my personal Web site. I wanted to see how my work in progress looked in Internet Explorer. On a Windows machine that's as easy as pie, of course, but on my Linux desktop it's not so simple. I usually grab my laptop and boot it into Windows if I need to check something in IE (or interact with a wrongheaded site that requires that browser), but this wasn't an option that day--so I apparently had no choice but to reboot my desktop (which dual boots), select Windows, fire up Internet Explorer, take a look, and boot back into Linux to continue my work.

As heavy power users, IT departments have a key part to play in reducing greenhouse gas emissions. And apart from the environmental impact, they need to make sure they don't exhaust their capacity. A recent Gartner report notes that 50 percent of data centres will have insufficient power and cooling capacity by 2008.

Just because a Web search engine can't find something doesn't mean it isn't there. You may be looking for info in all the wrong places.

For many moons now, PC publications have talked about ways to connect devices wirelessly. As far as wired connections went, innovations have seemed thin on the ground. However, a way of physically connecting devices using something called Powerline -- a concept that has been around for three or four years -- is now making its presence felt in the U.K.

The 2.6.19-rc4 prepatch release did not go quite as well as the developers might have liked; some confusion over the return type for an internal function led to an undesirable mixing of pointer and integer types in the depths of the block layer. As it turns out, gcc noticed this problem and duly issued warnings about it, but nobody saw them before the mistaken patch was merged and the resulting kernel shipped. This is, in other words, a problem which should have been easily avoidable.

Get Dapper Drake running on slower systems and prepare your Linux installation for attack with this Here's How.

Virtual computing is the flavour of the moment. Scott Spanbauer lets you in on the best ways to keep your os at arm's length.

There are installation CDs and Live CDs, but did you know that you can install Linux over the Internet as well?

Not all of us are ready to go completely linux. Here's how you can have your cake and eat it.