Today the jQuery team has released version 1.3.0 of their amazing JavaScript toolkit. It boasts a lot of great improvements, such as better selector performance, "live events" (YAY!!), drastically improved delegation filtering, overhauled HTML injection functions, et cetera. I haven't yet had a chance to play with it, but I think it will be quite fun once I do. I have a lot of Django-powered apps that are running on older versions of jQuery.

For anyone who's interested in learning more, check out the jQuery 1.3.0 release notes.

For the past 8 years or so, I've been very much involved with programming using the PHP scripting language. It is a powerful scripting language that suits building websites very well. PHP has a huge set of useful built-in functions, and more recent versions support object-oriented programming. I first started teaching myself PHP when I got tired of having to build each and every web page on my site manually. I hated having to change dozens of web pages just because I added a new link to my navigation. All sort of reasons like this prompted me to investigate PHP. Little did I know then that this language would occupy so much of my time in the future.

I rapidly learned that PHP offered much more than just allowing me to update one part of my website to change all pages. I started tinkering with all aspects of what PHP offered, and I'm still learning about it. After many years of searching, I finally found a programming language that was easy, fast, and efficient for my needs.

Through the years, I continued to develop various applications using PHP. I attempted to write my own forum/bulletin board software while I was still in high school. If I may say so myself, the forum really had some awesome concepts behind it. But my problem was that I lost interest too fast. I also built a very large application that reduced a 1.2GB MS Access database down to less than 15MB using PHP and MySQL. The new application offered many enhancements over the previous system. For one thing, it was much faster. Second, it allowed multiple simultaneous users to modify the database. Three, so far it has lasted more than 3 years, compared to the 1 year maximum that the MS Access solution always seemed to hit before it crashed.

Using PHP, I helped revolutionize the way one of the companies I work for developed websites. I built a simple in-house web framework that supposedly reduced development time by allowing us to forget about the mundane details involved in virtually every website and just get to the developing. In a matter of two weeks (with a full class load and another job), I managed to write an e-commerce solution for the same company using PHP.

Basically, PHP has treated me well over the years. But this post is not supposed to be about PHP. If that's the case, why have I rambled about PHP this whole time, you ask? Well, it's mostly to demonstrate that I have a lot of experience with the language. I have a pretty good feel for what it's capable of and how I can accomplish most anything I need.

With all of that in mind, I've encountered my frustrations with PHP. They may seem petty and moot to most people, but they have turned out to be the determining factor in what scripting language I prefer. Here is a short list of things I now despise about PHP:

• dollar signs ($) to signify variables -- while this is a useful feature, it becomes quite bothersome when you're programming all day long (at least it does for me). I'll get to why later.
• using an actual arrow (->) to access attributes -- most other modern programming languages simply use a period (.) for this functionality. I'll comment more on this and why it frustrates me later as well.
• lack of true object-oriented constructs -- in other object-oriented languages, like Java, if you have a string and you want to determine its length, you call the length() method of that string. In PHP, you call a function such as strlen($var). This sort of behavior plagues the language.
• too many unnecessary keystrokes -- as I mentioned before, all mutable variables are preceded by a dollar sign ($). That is 2 keystrokes (shift and 4) every time you want to refer to a variable, wheres most languages nowadays have none). Likewise, accessing attributes of objects in PHP uses an arrow (->), which is three keystrokes (minus, shift, and .). Most other object-oriented languages only require a period (one keystroke) for such functionality. The main reason I make such a big deal out of the number of keystrokes is simple. The more keystrokes a program requires, the more likely you are to have bugs. The fewer keystrokes a program requires, the less likely it is that your program will be broken. It boils down to maintainability. Also associated with the number of keystrokes is the pure laziness within me and most other programmers.

These frustrations have been bothering me for several years now. I continued using PHP mostly because it's so widely supported, but also because I could not find a suitable replacement for it. I investigated a few others, but they apparently didn't have a great influence on me right now because I don't remember any names.

When the whole Ruby on Rails bandwagon was rolling through town, I decided to hop on to see what all of the hubbub was about. I started studying the Ruby script language, and I found that it had some really neat things about it. It uses a more solid approach to object-oriented programming, which I really liked. I also noticed that it employs some intriguing structures for accomplishing things in ways I've never seen before. Despite these things, Ruby still didn't seem like a viable replacement for my PHP. It didn't come up to snuff in performance in many cases, so I essentially abandoned it.

For at least a year now, I've been interested in learning Python. I've heard a lot about it over the years, but I just never seemed to make the time to actually sit down and study it. That is, not until about the beginning of August of 2007. After I made my decision that Ruby and Ruby on Rails weren't quite up to par for my needs, I stumbled upon the Django Project, which is a web framework similar to Ruby on Rails, only built using Python.

I decided this was my chance to actually sit down and learn a little about this "Python" so I could see what it had to offer. I mostly used Django as my portal to Python. As I started learning Django, I became more and more familiar with the way Python works and how I work with Python.

At some point in time, I decided that I actually liked Python, and my wife let me buy some really cool books to help me learn it. By the beginning of October 2007, I had convinced my supervisor at work to let me start building websites using Django instead of our home-grown PHP framework.

And here comes a story. This is the main reason I blabbered about my experience with PHP so much at the start of this article. Again, after all these years, I feel very confident that I can do just about anything I want efficiently and elegantly with PHP.

Back in October of 2006 (after using PHP for some 7 years), I was asked to write a PHP script to parse some log files and output various bits of information in a certain format. After maybe a week, I had a script that did the job fairly well. Most of the time it worked, but there were occasions when it didn't and I had to fix it. The script turned out to be 365 lines of code with very few comments scattered throughout. It's also a maintenance nightmare, even for me.

In October of 2007, I rewrote that same script in Python. After only a couple days, the script seemed to be perfect. It did its job, and it did it well. With comments for just about every single line of code, the Python version of the script took up a mere 118 lines of code. Take out the comments and it is 56 lines of code. The script is several times more understandable and maintainable than its PHP counterpart. I also believe that it is much more efficient at doing its task. Keep in mind that I had only been using Python for about 2 months at this point in time.

It's been through various experiences like the log parser that I have decided I prefer Python over PHP. Obviously, I'm not quite as comfortable with it as I am with PHP, but I don't feel too far behind. Now, less than 6 months after deciding that we'd use Django at work, I don't think my supervisor could be happier. Building a typical website with our PHP framework takes between 1 week and a couple months. Thanks to Python and Django, most of our websites can be "ready" within just a few hours. That time assumes that the website's design itself is ready for content to be put into it and also that the client does not require custom-designed applications.

Python and Django have helped revolutionize the way we do things at work, and I can hardly stop thinking about it. Python fixes nearly all of the frustrations I had with PHP. The frustrations it doesn't take care of are worth the sacrifice. Python is capable of object-oriented programming. It uses a period (.) to access object attributes. Variables are not preceded by some arbitrary symbol.

Also, the fact that Python code can be compiled to bytecode (like Java) is enormously beneficial. Each and every time a PHP script is executed, the PHP interpreter must parse the code. With Python, the first time a script is executed after an edit, the program is compiled to bytecode and subsequent executions are faster. That is because the bytecode is processed directly by the Python Virtual Machine (as opposed to being compiled to bytecode _each_ time and then executed). Python also offers a vast amount of standard library functions that I would really appreciate having in PHP. But from now on (at least for the foreseeable future), I will try to do all of my scripting in Python and leave PHP for the special cases.

The Linux kernel is the core component in any Linux distribution. Without a kernel, your computer would be essentially useless. It is the piece of software which allows interaction between you, your computer's applications, and your computer's hardware. With such a powerful role in your computing experience, it is important to keep your kernel up-to-date. Each new release provides more hardware support and many performance enhancements. It is also important to keep your kernel up-to-date for security purposes.

Let's upgrade our Linux kernels together. I will walk you through each of the steps I take, from beginning to end, to upgrade my kernel. Just as a warning, I prefer to do the whole process on the command line, so you might want to pull up a terminal, konsole, xterm or whatever you prefer to use for your command line operations.

First you need to download the kernel source code. Many Linux distributions provide specialized editions of the Linux kernel. Typically, you don't want to manually compile and install a custom kernel for these distributions. This does not mean that you can't, it simply means that you might be better off using the "official" kernels for your distribution, which can usually be obtained through your distribution's package manager. You can get the official, 100% free, and complete Linux kernel source code from http://www.kernel.org/. Look for "The latest stable version of the Linux kernel is:" and click the link on the F on the same line. Currently, the latest stable version is 2.6.20, and that's what I'll be using for this tutorial. Please note that commands which begin with a dollar sign ($) are executed as a regular user and commands beginning with a pound sign (#) are executed as a superuser.

$ cd /home/user/download
$ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.20.tar.bz2

Now login as the superuser, and navigate to the /usr/src directory. Then extract the kernel source into that directory.

$ su -
# cd /usr/src
# tar jxf /home/user/download/linux-2.6.20.tar.bz2

You probably already have a symlink or shortcut called linux which points to your most recent kernel. If you do, delete the link and create another link to the new source tree. Then go into your kernel source tree.

# rm /usr/src/linux
# ln -s /usr/src/linux-2.6.20 /usr/src/linux
# cd /usr/src/linux

I like to identify each compile of my kernel uniquely, to make sure that I'm using the right one. To do that, you have to modify your Makefile

# vi Makefile

You will see the following lines, or something similar, at the very top of the file:

VERSION = 2
PATCHLEVEL = 6
SUBLEVEL = 20
EXTRAVERSION =
NAME = Homicidal Dwarf Hamster

Change the EXTRAVERSION property to something you want to use to identify this kernel. I will use -jcv1

EXTRAVERSION = -jcv1

The rest of the Makefile should be fine. In fact, I discourage editing Makefiles unless you know what you're doing. This next step is totally optional, but I like to do it to save some time. You can copy your existing kernel's configuration file in order to have a very similar kernel configuration. My previous kernel version was 2.6.19.1, so this is the command I use:

# cp /usr/src/linux-2.6.19.1/.config /usr/src/linux/

Then I run make oldconfig or make silentoldconfig to update my older kernel configuration file to be able to handle newer features. If you use oldconfig you are required to specify whether or not you want the new features included in your kernel, whereas silentoldconfig will use the defaults determined by kernel developers (they usually know best), asking for minimal input. Let's update our configuration file and then customize it by running make menuconfig (there are several options here, such as make xconfig and make gconfig, but I prefer the text-based menuconfig; there is another you can run by using make config, which runs through each and every option available--it's scary).

# make silentoldconfig
# make menuconfig

menuconfig is a graphical command line application which lets you navigate the features offered by the kernel. Each computer is considerably different from the next, so it really does no good to provide a list of things that I tweak. However, it is important to note what some of the symbols are in the menuconfig utility:

• M = Module. Modules are loaded when they are required and can contribute to the speed of your system
• * = built into the kernel. These are typically things which are necessary for your machine to function properly, such as support for your root file system.
• X = exclusively selected. You'll see this when you select what type of processor you have, for example.

One thing to note before we go further is MAKE SURE YOU KERNEL HAS BUILT-IN SUPPORT FOR YOUR ROOT FILE SYSTEM!!!! My root file system is reiserfs. In my configuration, I made sure that reiserfs was marked with a star. If you don't do this, your kernel won't boot and you will be very frustrated. Trust me.

Your computer is probably quite different than mine, so you might want to just poke around and see if you recognize things that deal with your computer's hardware. Once you are done tweaking your kernel configuration, exit the configuration utility and make sure the configuration is stored in /usr/src/linux/.config

Next we get to build and install the kernel. After that, we have to add an entry to our boot manager so that we can try out our new kernel. The compilation part usually takes just about a half hour on my 2.2Ghz Turion64 processor with 1.25GB of RAM. It takes about 6 hours on my 300Mhz Pentium 2 with 32MB of RAM. Let's find out how long it takes for you to compile your kernel!

# time make
...
real    27m29.663s
user    23m34.476s
sys     2m56.575s

Now let's install the modules and install the appropriate files in the boot area:

# make modules_install
# make install

This is the part that always used to mess me up. I use Slackware Linux, which is more UNIX-ish than most distributions. It's actually the oldest surviving Linux distribution to date, but that's another story. For some reason, the make install command doesn't always work with Slackware. There is a process I use to setup my boot directory when I compile a new kernel. I wrote a simple shell script called fixkernelinstall to take care of it for me:

#!/bin/bash
# Configure my computer for a new kernel
# Author: Josh VanderLinden
# Assisted By: Dan Purcell

# if the user didn't supply a kernel number, ask for it
if [ $# -eq 0 ]; then
    echo -n "Kernel: "
    read kernel
else
    kernel=$1
fi

# determine root partition
echo "Determining root partition..."
rootpart=`mount -l | grep ' / ' | cut -f 1 -d\ `
echo "Root partition is $rootpart"

# copy kernel configuration file
cp /usr/src/linux/.config ./config-$kernel

# now rename everything
echo "Renaming files..."
mv System.map System.map-$kernel
mv vmlinuz vmlinuz-$kernel

# if the config file exists and it's a symlink, remove it
if [ -f 'config' -a `stat config | grep -c 'symbolic link'` = '1' ]; then
    echo "Removing link to configuration file"
    rm config
else
    # otherwise it might be important
    echo "Renaming configuration file"
    mv config config.bak
fi

# Link files
echo "Creating symlinks..."
ln -s System.map-$kernel System.map
ln -s config-$kernel config
ln -s vmlinuz-$kernel vmlinuz

# Update lilo
echo "Adding entry to /etc/lilo.conf for $kernel"
echo "image = /boot/vmlinuz-$kernel" >> /etc/lilo.conf
echo "  root = $rootpart" >> /etc/lilo.conf
echo "  label = $kernel" >> /etc/lilo.conf
echo "  read-only" >> /etc/lilo.conf
echo "Linux kernel $kernel has been configured."
echo "Please check your lilo configuration and run lilo before rebooting"

I'm not an expert on shell scripts, so please feel free to offer suggestions for doing things better if you know how. This script uses the kernel version (given by the user) to setup by /boot directory properly. In my case, I run the script as such

# cd /boot
# fixkernelinstall 2.6.20-jcv1

And the output is something like:

Determining root partition...
Root partition is /dev/hda5
Renaming files...
Renaming configuration file
Creating symlinks...
Adding entry to /etc/lilo.conf for 2.6.20-jcv1
Linux kernel 2.6.20-jcv1 has been configured.
Please check your lilo configuration and run lilo before rebooting

As you can see from the script, I use LILO instead of the arguably more popular GRUB. Either one works for me, but LILO is sufficient for my needs. If you want to use the same kind of script for a GRUB installation, just change the LILO part at the end to something like:

echo 'Adding entry to /boot/grub/menu.lst for $kernel'
echo '  title Linux on ($rootpart)' >> /boot/grub/menu.lst
echo '  root (hd0,4)' >> /boot/grub/menu.lst
echo '  kernel /boot/vmlinuz-$kernel root=$rootpart ro vga=normal' >> /boot/grub/menu.lst

Make sure you change the line with root (hd0,4) to fit your setup. With GRUB, you don't have to worry about applying changes to see the menu entry at boot. It's automatically there. With LILO, however, you have to actually apply changes each time you make them. You do this by running the lilo command as the superuser:

# lilo
Added Windows
Added Linux
Added 2.6.20-jcv1 *

The star (*) signifies the default kernel to boot. Make sure that your root partition is correctly specified in your boot loader configuration. My root partition is on /dev/hda5, but yours may be (and probably is) on a different partition. If you fail to specify the correct root partition, your system will not boot that kernel until the configuration is fixed. GRUB makes this a lot easier than LILO.

And this is the point when you start to cross your figures and hope that your computer doesn't blow up... We get to reboot our computer and hope that our configuration file plays well with our computer. So, let's do that! See you in a few minutes (hopefully).

# shutdown -r now

So here I am, back on Linux on my freshly-rolled kernel. I hope you are as successful as I have been this time around. Keep in mind that you have to reinstall custom kernel modules if you installed others while you were on your other kernel. For example, I use ndiswrapper to access wireless Internet. I have to recompile and reinstall the ndiswrapper module and device drivers before I can use wireless. Likewise, I have VMWare Server on my laptop, which installed special modules. I have to run vmware-config.pl to reconfigure VMWare Server for my new kernel before I can run any virtual machines.

To summarize, here are the commands that I used in this tutorial. Remember that lines beginning with a dollar sign ($) are executed as a non-privileged user, while lines beginning with the pound sign (#) are executed as the superuser (root).

$ cd /home/user/download
$ wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.20.tar.bz2
$ su -
# cd /usr/src
# tar jxf /home/user/download/linux-2.6.20.tar.bz2
# rm /usr/src/linux
# ln -s /usr/src/linux-2.6.20 /usr/src/linux
# cd /usr/src/linux
# make clean
# vi Makefile (to change EXTRAVERSION to -jcv1)
# cp ../linux-2.6.19.1/.config .
# make silentoldconfig
# make menuconfig (just to ensure settings were good)
# time make
# make modules_install
# make install
# cd /boot
# fixkernelinstall 2.6.20-jcv1
# vi /etc/lilo.conf (to make sure things were good)
# lilo
# shutdown -r now

I hope that you are able to use this tutorial to successfully install or upgrade your kernel. Good luck! Any comments or suggestions are welcome!