For most people, the word kernel inspires visions of corn, wheat or possibly fried chicken. Here in the Linux world, although we still might appreciate The Colonel's 11 herbs and spices, kernel means something much more profound. The kernel is Linux. Sure we add lots of fancy programs, interfaces and command-line tools, but in the end, Linux is the kernel. This month, we focus on it.
Do you ever smugly brag about the uptime of your Linux machines to your Windows friends? I don't know about you, but every time I do, either the power goes out or I have to reboot due to a kernel upgrade. Thankfully, Waseem Daher shows us a bit about Ksplice. Using Ksplice, software updates can be applied without rebooting the Linux machine. Add to that a battery backup, and we can all brag to our friends about uptimes. Unless, that is, we're running an old kernel and they come over 498 days after we first started. (Uptime wraparound hasn't been a problem for a while, but most of us still remember it.)
One of the jobs the kernel has is to schedule CPU time for different processes. We have a few different looks at kernel schedulers: a real-time scheduler that Ankita Garg explains and a “Completely Fair” scheduler that Chandandeep Singh Pabla tells us about. One of the great strengths of the Linux kernel is its flexibility, and that should be fairly evident after reading this month's issue.
All Linux admins worth their salt know that a properly maintained Linux machine is a fairly secure beast. “Fairly secure” usually isn't satisfactory, however, and that's where people like Mick Bauer come into play. This month, he continues his series on setting up a secure proxy, but he also interviews Anthony Lineberry about /dev/mem rootkits. The best security specialist is a paranoid security specialist, and Mick does his best to worry us all a bit.
If all this kernel talk is beginning to worry you that this issue has nothing for you, fear not! I'd be lying if I claimed to do any work with the kernel anymore. In fact, not since the days of compiling Debian kernels for my PowerPC hardware have I even used anything but the stock kernel that comes with my distro. We realize you might fit into that boat as well, so we've stuffed a ton of other stuff between these covers just for you. (And maybe for me.)
Kyle Rankin shows us how to join the instant-messaging bandwagon without ever leaving the comfort of our IRC windows. With Bitlbee, you can pretend everyone on the planet uses IRC, even if they're using the dreaded MSN Messenger. To follow that up, Kyle and Bill Childers are back to their spatting. This time, they're arguing over the usefulness of Twitter. As a Twitter user myself, I think I lean toward Bill's side this month, but feel free to choose for yourself.
Dave Taylor takes us back to the command line as we dissect the English language a bit. Of course, we have the computer do the dirty work, but in the end, you'll learn a bit about scripting language and the English language. Reuven M. Lerner teaches us about Fixtures and Factories in your Rails projects. If you program in Rails and work with databases, you won't want to miss Reuven's column.
We didn't stop there. Marcel Gagné demonstrates eyeOS—an entire operating system you can control from a Web browser. You get to set up a little cloud computing system of your very own! Add to that our normal list of reviews, product announcements and regular columns, and this issue is bound to please even the most obscure Linux user. So go get your can of corn kernels, a bag of wheat kernels or even a bucket of chicken, and sit back to enjoy this issue of Linux Journal.