ArchLinux使用手记

Motivation

I have been an Archlinux user for a while now. This is an attempt at a review, for people who have experience with other distributions, and are searching for something new/different.

I won't go into detail about installation that much. Most reviews cover installation. That is well covered territory. This review will attempt to touch on things that *I* found important and exciting about Archlinux during the course of my early use.

If you do want some information about installation, check out the following links:

• Archlinux Installation Guide
• Quick Custom Installation
• Fast Arch Install from existing Linux System
• Quick Arch Install

Be aware that some of that information is a bit dated, but it is useful to provide an idea about what an installation entails.

Instead of talking about Installation, I will talk about the following features that I feel set Archlinux apart.

• BSD-like Init system
• Rolling Release System
• Pacman
• ABS
• AUR

BSD-like Init system

Archlinux uses an init system that is very similar to a BSD init system. Daemon start scripts are stored in /etc/rc.d/. You start and stop daemons manually via the following syntax: /etc/rc.d/daemon start or /etc/rc.d/daemon stop

That handles how to start/stop from the command line, but what about on boot?
This is where the bsd-like init comes in. Archlinux has a file, /etc/rc.conf, which holds system initialization configuration information. You specify in this file which daemons start at boot, the IP addresses of your network interfaces, any system routes, etc.

The Archlinux wiki has a good example the rc.conf file.

Arch has run levels, which you can set by editing inittab, but they are used in a limited fashion. Runlevel 0 is used for shutdown, and by default runlevel 5 is used to spawn a *dm. You can modify /etc/inittab to change runlevel, or change the re-spawn runlevel of the *dm. You can also just add your *dm to the DAEMONS array.

Other than that limited use, runlevels just don't come into play. Most Arch users always use runlevel 3, whether or not they use X.

I like this simple approach. It makes it much easier to track the initialization sequence through the init files. This is a good example of the KISS (Keep it Simple, Stupid) principle.

Rolling Release System

Archlinux uses a Rolling Release System (RRS). This is a bit different than most distributions. Most distributions release a version as a monolithic thing. Users have to update their systems running on the old version, to the new version. In between version releases, the distribution provides minor updates and security fixes.

Archlinux, with the RRS, works a bit differently. Arch uses version numbers for the installation CDs. This is a version of the installation CD itself, not a version of the Archlinux system.

You install from the CD, and then update your machine with the package manager (we will talk about Pacman in the next section). In this way, you never need to run any monolithic update to the next version. You never need to reinstall when a new CD is released. You just keep updating your system. There are people that have not reinstalled their Archlinux systems from their initial install from several CD versions ago. Their systems are just as up to date as someone who installs today with the current CD version.