Liam 'Lamsey' McBrien's Website: Linux/Unix Information

Unix, Linux and BSD (oh my!)

An 'Operating System' is a collection of pieces of software which allows a computer to run general-purpose applications. Most users of desktop PCs in the world use a variant of Microsoft Windows as their operating system, but Windows is expensive and in some ways isn't that well designed. Thankfully there are a great number of other kinds of operating systems out there, most of which are freely available to download and use. Let's take a brief look at what's out there.

Unix

Unix is the granddaddy of modern operating systems. With one notable exception (Windows), pretty much all the OSes out there today owe a fair amount of their core design to Unix - from the Linux mini-distro on your mobile phone to the graceful and pretty MacOS X.

There are many different versions, flavours and derivatives of Unix. 'Pure' Unix systems such as AIX, HP-UX or Solaris adhere closely to the Unix standards and conventions of old and are extremely powerful, stable systems. Sun's Solaris is notable for its continuing innovation and its availability for free download and use.

Today, pure Unix is rarely seen outside of the server room as it's geared towards high-end, secure, stable systems without the multimedia capabilities of modern desktop OSes. On the desktop, you're far more likely to encounter a derivative of Unix such as Linux or BSD, which are usually freely available and easier to use out-of-the-box than a pure Unix.

Linux

The origins of Linux lie in two projects: a set of core utilities written by the GNU project headed by Richard Stallman, combined with a kernel written by Linus Torvalds. Today, the Linux world has sprawled into a labyrinth of different distributions and variations, each with their own strengths and weaknesses.

Almost all Linux distributions ('distros') are freely available to download and use, and most encourage user participation in their development. Linux is very much a product of a community, rather than a monolithic proprietary OS. With this comes the benefits of rapid, user-oriented development, however fragmentation and interoperability issues can sometimes cause problems.

One of the handy things about Linux is it's possible to run many distros from a CD without the need to install on a hard disc. These 'live' distros can be very handy for evaluation and troubleshooting.

LinuxLive Distros

LinuxLive CDs are special versions of normal Linux distros which can be run from a boot CD without installing Linux on a hard drive. Just boot from the CD and Linux will load up.

They are great for having a look at Linux's different distros ('flavours') and also for booting into a PC which has a problem which prevents it from booting from a hard drive (or even if there's no hard drive present).

The original (and, many would say, best) live distro is Knoppix. Some of the other popular LinuxLive distros are Suse Live, Gnoppix and Slax. Give them a go - you may well be surprised at how powerful Linux is.

Full Linux Distros

So you're ready to take the plunge and enter the world of Linux? First thing you'll want to do is get a hold of some installation images for one of the plethora of Linux distros available.

Common distros to start out with include Fedora or SuSE, while more advanced users might like to get their teeth into Debian or Slackware. Another distro which is gaining in popularity amongst both novice and advanced users is Ubuntu.

All sorts of linux distros can be found at LinuxISO - this site provides a list of mirrors for most popular distros. Everyone's got their own preferences for distros, so make your own mind up! Some factors to consider when choosing are:

Which desktop enviroments are supported? The most common are KDE and GNOME, which are subtly different in interface and which offer different suites of utilities and programs.
How are packages managed? Is there a simple, popular package system such as SuSE's YaST or Red Hat's RPM, or are you going to have to compile all your software and drivers from scratch?
What sort of user is the distro aimed at? Do you want a simple, stable system to use in your company? Do you want a glitzy, cutting-edge OS with all the latest bells and whistles? Are you after something minimalistic and simple which just gets the job done?

Once you've gotten your install CDs for your preferred distro, simply slap them into your PC and boot from disc. All major distros have simple, complete installers which will walk you through getting Linux up and running.

BSD

Outside of Linux the most popular Unix variant is the BSD family. Originally developed by the University of Berkeley, BSD systems lie somewhere between Unix and Linux in terms of focus, support and usability. BSDs are commonly used as a home desktop OS for Unix enthusiasts, or as a stable home server OS.

While BSD is not as widely-known as Linux or as popular, it still has a large base of support and, in true Unix tradition, comes in a number of flavours. There are three main open BSD variants: FreeBSD, NetBSD and OpenBSD. Apple's proprietary MacOS X also uses a BSD-based kernel, although its graphical shell is radically different from other BSD systems.

Roughly speaking, the three main variants of BSD can be categorised thus: FreeBSD is focused on providing high performance, especially for networking applications; NetBSD's primary focus is interoperability and wide platform support; and OpenBSD (despite the name) focuses on extremely strong security. Apple takes a different approach with MacOS, focusing strongly on usability and simplicity of design.

Software

While most Unix-like distros come with an astonishing amount of preinstalled software, you'll want to try out other software. The open-source movement provides more software than you can shake a very large stick at, and it's almost all freely available to download and use. To that end, the following sites will prove useful to you:

Most open source projects written for Linux or Unix-like systems can be compiled and run on pretty much anything except Windows, through the use of interoperable languages and libraries such as Python and GTK+. If you're lucky you might even find pre-compiled binaries for your OS of choice!