Friday, June 22, 2007

Arch Linux: An Observational Review

Having spent two solid years using Redhat/Fedora products, I began to look for a new Linux distribution that would satisfy my needs as a user but eliminate some of the bloat of the RPM-based distribution I’ve grown so accustomed to. I tried all of the more popular distros: Ubuntu, SuSE, Debian and MEPIS but none of them seemed to possess any of the more streamlined qualities I was looking for. My quest eventually led me to Arch Linux.

Arch Background
Arch is a relatively young distribution that has its roots in Canada. Its founder, Judd Vinet, professes the Arch Way on the distro’s Wiki:
freedom of choice, keep it simple, learning, and user-control

These principles have shaped Arch into an advanced, lightweight distribution intended for the more experienced Linux user.

If you plan on installing Arch, you should have at least a moderately experienced background installing and using Linux systems. Arch is not impossible for newbies to install and use, in fact there is a section of the Arch wiki devoted explicitly to this demographic, but it will require you to configure some aspects of your system by yourself. While this guide requires at least a cursory knowledge of your system, it does walk you through some of those manual configurations. Still, you’ll need to know something about your hard drive’s partitioning scheme and your network layout.

On that note, I feel obliged to mention that Arch seems to be a distribution that functions best on a high speed Internet connection. This isn’t mandatory but if you plan on installing a Desktop Environment/Window Manager (KDE, Gnome, XFCE, Fluxbox…) you’ll have to download it from Arch’s repositories (they’re not available on the install CD) and this process can be difficult on a dialup connection.

Moving on, my Arch install process was split up into 8 steps:

1. Run Setup
2. Prepare Hard Drive
3. Select Packages
4. Install Packages
5. Configure System
6. Install Kernel
7. Install Bootloader
8. Exit Install

1. The first step is simple, just run /arch/setup from the command prompt when you boot your computer with the Install CD in your CD-ROM drive.

2. Preparing the hard drive can be automated by the install process but this automation will blow away your entire hard drive. If you need to keep a Windows or other Linux partition around, you’ll have to configure this step yourself. Don’t fear! It’s not difficult if you know which partitions you need to keep.

3. By default, Arch only installs a minimal system, allowing you to fine-tune your system as you see fit. However, you can add some packages that you know you’ll need by checking the boxes next to the software that you want installed. Arch recommends only installing the default package set but you are free to add what you need. Again, this process is very straightforward.

4. Installing the packages you’ve selected requires pressing Enter on the keyboard. How difficult is that? The process may take a couple of minutes, depending on the size of your package selection.

5. Configuring your systems will probably be the most difficult part of the install process for you. You can choose not to edit any system files at all but this may hinder your system’s functionality and performance after the install process. This step involves editing some of the files in /etc including rc.conf, hosts, fstab, modprobe.conf, modules.conf, resolv.conf and profile. If you have no idea what any of these files do or don’t even know where to start in terms of editing them, don’t worry, the install guide explains each of their functions within the system and it can help you determine what you do need to add/change/edit, if anything.

6. Installing the kernel essentially means just choosing which kernel is best for you but Arch recommends installing the 2.6.x kernel with support for SATA/SCSI/IDE. The actual installation of the kernel will be done for you by the installer.

7. Same goes for installing the bootloader. Just choose if you want GRUB or LILO. I chose GRUB simply for familiarity’s sake.

8. Exiting the install will reboot your computer and drop you into a command prompt.

All told, it took me about 10 minutes to complete the install and most of that time was spent setting up a partitioning scheme that included a Windows partition, another Linux partition, a swap partition and a home partition that I planned on sharing between the two Linux systems.

System Setup
You now have a fully functioning Arch system but we’re not done yet. At the command prompt, you are greeted by a text login screen. Login with the username of root and no password. The first thing you’ll probably want to do is set a password for root. This can be done with the following command:
passwd root

You’ll then be asked twice to enter a password for root. Remember that the next time you log in as root, you’ll have to enter that password. The next thing I recommend doing is to set up a regular user. As root, you can do this with the following command:
useradd –m –s /bin/bash myuser

Replace “myuser” with the username that you wish to have. It would then be wise to create a password for that user. This can be done with the same method that you created a password for root.

Now that you have a proper user configuration, you’ll want to connect to the Internet and use pacman to update your system. The first thing to determine is if your machine has an active Internet connection. An easy way to do this is to ping Google:

If you get a response from Google (i.e. you received packets from them) you’re ready to proceed. If you got an “unknown host” error, you still have some tinkering to do.

First, check to see if you have an IP address with

If you do, check the contents of your /etc/resolv.conf file. This file tells the computer where to look for a DNS server. If the file is not populated with the IP addresses of your ISP’s DNS Servers, add these two lines to it:

These two IP addresses are for the OpenDNS servers that are freely accessible. The last thing to check is your routing table. If you’re behind a router, say on a home network, you’ll have to add that router’s IP address to the routing table as the default gateway. Details for this procedure can be found later in the article.

Package Management
As a somewhat experienced Linux user, hopefully you are familiar with the concept of package management. Maybe you’ve used package managers like apt-get, yum, urpmi or portage. Well, Arch Linux has its own package manager and it is called pacman. Arch is a binary based Linux distribution that uses .pkg.tar packages. Using pacman to install these packages will keep you from experiencing the inevitable headaches that come with trying to install source packages yourself.

Like other package managers, pacman has access to online repositories, from which it can install any software you’d like. There are two default pacman repositories: current and extras. Most software can be retrieved from one of these two but there is also a third repository that you can add if you wish. This third repository is the Arch User Repository (AUR) and contains packages contributed by Arch users. With these three repositories, you would be hard-pressed to find a piece of software you need that could not be installed with pacman. Instructions for using the AUR can be found here.
Pacman usage is rather straightforward. I won’t go into great detail on this subject (you can find an entry for pacman on the Arch Wiki) but I will give you some basic commands that you’ll need to install/remove packages and update your system. Pacman is divided into operations (which are denoted by capital letters) and options (denoted by lowercase letters). Keep in mind that these commands require root privileges. To perform a full system upgrade, execute:
pacman –Syu

The “S” option syncs the local package database (on your machine) with the repositories’ package database. The “y” option refreshes the package list on your machine with the package list from the online servers. The “u” option performs the actual upgrade. You should execute this command after installation and everyday thereafter. To install a package, execute:
pacman –S package_name

We’ve already mentioned what the “S” option does, appending a package name to the end of the command will search the online repositories for that package name, download the package (along with its required dependencies) to your machine and install it. To remove a package, execute:
pacman –R package_name

This is a generic remove command. It is recommended that you consult the Arch Wiki and pacman manual for a more refined method of removing packages. To query the online repositories to check for the existence of a certain package, execute:
pacman –Ss package_name

The “s” option is a search operation for the sync databases. To search your own system to see if a package is already installed, execute:
pacman –Qs package_name

The “Q” option queries the local database and, combined with the “s” option, can tell you whether or not a certain package is installed.

As you can see, pacman is very easy to use but I must reiterate: read through the pacman page on the Arch Wiki and the pacman manual. After your install, you can use pacman to install a Desktop Environment/Window Manager. Consult the Wiki for more details.

Personal Observations
Well, so far I have tried to maintain a degree of objectivity; giving new Arch users a rundown of the experience I had installing Arch and advising them on some of the tips that helped me get a working system. I have been using Arch for approximately two months and I have grown very fond of it. It has fulfilled my needs as a lightning fast distribution with a simple philosophy. It has the added bonus of having a terrific foundation. The Arch Wiki, discussion board and AUR are all officially endorsed by the project and can be found on the same website.

I will now try to describe a couple of the problems I had installing and setting up my system and how I resolved them:

• Initially, the installer recognized my hard drive as hda (as most distributions did seeing as how it is an IDE drive). However, after installation and running a pacman -Syu, I rebooted to a terrible error about superblock not describing a correct ext2 filesystem. After much googling, I realized that the system upgrade had replaced my kernel with a new one that the new one recognized my hard drive as sda(it seems most of the newer releases of the major distributions are doing this now).The fix was fairly simple, I just had to change the entry in /boot/grub/menu.lst to compensate for this change.
• I also did not have an active internet connection. My router had leased me an IP address, my /etc/resolv.conf had set up the appropriate DNS servers but I couldn't connect to the internet. After yet even more googling, I found that I had to set my router as the default gateway in my routing table. This was done with the following command:

route add default gw dev eth0

What I really like about Arch is that all the software I need is available in one of the three repositories. As a long time Fedora user, I was used to the process of importing third party repositories to install software that I needed. I was always weary of that method but I’m happy to report that I have now equipped my Arch system with every piece of software I’ve ever used on Linux (with the superb guidance of the Arch Wiki), and all of it was contained in Arch’s repositories. There’s also no need to download the latest releases of Arch as they are made available. Simply running pacman –Syu will upgrade your system to the latest.

Another thing I really like about Arch is that it’s lightning fast, even with a Gnome desktop. There are significant performance improvements over any distribution I’ve used in the past. If I ever got into any of the lighter WM’s like Openbox or Fluxbox, I can imagine just how powerful the system can get.

The last thing I want to mention about Arch is the Arch Build System (ABS). The ABS is used to build packages for software that is not yet available and to customize existing packages for your system. You would probably not have a need for the first option but if you have auxiliary hardware that needs to be integrated with the kernel, it may be necessary to compile drivers using the ABS.

I may have found my new everyday distribution. Arch is very fast and efficient but that performance doesn’t come at the cost of ease of use. Pacman is the best package manager I have used; anything you need to know how to do can be found on the Arch Wiki and any software you need can be found in the Arch repositories. I would encourage anybody looking for a simple, fast Linux distribution to give Arch a test drive. If you have a good knowledge base with Linux systems, you may find yourself to be a devoted Archer.

Thursday, June 21, 2007

First Blog Post

Somehow you've straggled across my blog. I don't know how; I haven't linked to it anywhere. But anyways, I'll post here anything I think is interesting or useful to others. Most entries will probably be about or relating to Linux. I'm a big fan of open source software and am willing to help anybody make the transition to it if they so desire.

Now a little about myself:
I am a software engineer for a government contractor here in Northern Virginia. I have experience with various languages including, but not limited to Java, C/C++, Perl, Python and Bash. I also have experience with Information/Network Security, various protocols and server applications. My knowledge is nowhere near perfect (nobody's is) but I am willing to help you out with what I can. Most of this knowledge is centered around Linux environments but not entirely. I am a proficient Windows user.

I graduated with a Bachelor's Degree in Computer Science with a minor in Mathematics and I am currently working towards a Masters Degree in Information Security. I enjoy golfing, fishing and watching all kinds of sports but most of all, I like to spend time with good people.

I guess that's about it for now. If I think of anything to talk about, I will post it here and you can feel free to use whatever advice you can take from this pathetic little blog.