Tying a LAN of computers together to do cooperative work isn't a new idea. Combining several thousand computers spread across the globe into a commodity service like water or electricity is. But is the "computing grid" ready for us to plug in? Here's a report.
Have a Linux machine and a few terabytes of data to store? Tired of running fsck for hours? Perhaps it's time to consider a journaling file system. Linux has four to choose from: Ext3, XFS, JFS, and ReiserFS. Learn how journaling file systems work, how easy it is to adopt one, and discover just how large a petabyte really is.
In the May 2002 Power Tools column (http://www.linux-mag.com/2002-05/power_01.html), we looked at one of the most compelling features of zsh: its ability to complete often-used command-line arguments and switches. If you were tempted to drop bash in favor of zsh, don't switch just yet -- bash still has a few tricks up its sleeve.
This month we continue our look at the steps required to harden a Linux system by considering how Linux services can be secured. In fact, securing system services -- subsystems like printing and electronic mail, file and web serving, and remote access (telnet, ftp, rlogin, rsh, imap, and so on) -- represents a large part of the hardening task.
How can you locate something in the filesystem with the least amount of work? You might be tempted to use a graphical (GUI) file manager, but in many cases the command line is faster. If you do a lot of work with your system, learning some pathname power tools can save you a lot of time.
One of the measures of success of a Beowulf cluster is the number of people waiting in line to run their code on the system. Build your own low-cost supercomputer, and your cycle-starved colleagues will quickly become your new best friends. But, when they all get accounts and start running jobs, they'll soon find themselves battling each other for the limited resources of the machine.
When running a Web site of any size, it helps to learn about the visitors you're attracting. The traditional solution for monitoring Web traffic is a log file analysis tool such as analog (http://www.analog.cx). analog is very fast, but what if you'd like real-time or near-real-time statistics? You could run analog from cron every five minutes, but what if you also want to issue ad-hoc queries against your logs to answer very specific questions like, "What's the average number of pages that each Internet Explorer user views?"
While most of the changes in Java 2 Standard Edition Version 1.4 (J2SE 1.4) are relatively minor, programmers who work with input and output received an embarrassment of riches in the form of the java.nio package.
Since the first version of Unix back some three decades ago, the fork() system call has been the normal way to get many things to happen at once. Forking is a very nice (some say "elegant") model of concurrent execution: individual processes have entirely separate address spaces, with little chance of interference from other tasks, at the cost of a lot of overhead for interprocess communication.
Last month, we talked about writing portable code and focused on how to use feature test macros, coding standards, and emulation of uncommon functions to make porting even easier. This month, we'll talk about portable build systems -- tools you can use to easily build that portable code on a variety of target platforms.
Maybe it's just me, but I'm starting to get this funny feeling about LinuxWorld Expo. It seems like every time it's held, it receives a huge amount of media attention, and everyone always says the same things. Stuff like: "At this show it became clear that Linux is ready for prime time," or "The show made it clear that enterprise customers are finally starting to take Linux seriously."
