Linux overview

What is "open source"?

A short introduction and the definition of the term, part of the www.opensource.org web site.

Licenses

The GPL and LGPL and a quite complete list of licenses.

Documentation

The Linux Documentation Project"
(in particular, look at the HOWTOs...)
a way to keep yourself informed, the Linux Weekly News website.
news for nerds (not restricted to linux), Slashdot.

Linux, the big picture

Linux is a clone of the operating system Unix, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net. It aims towards POSIX compliance. It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and TCP/IP networking. Linux was first developed for x86-based PCs (386 or higher). These days it also runs on Compaq Alpha AXP, Sun SPARC, Motorola 68000 machines (like Atari ST and Amiga), MIPS, PowerPC, ARM and SuperH. Additional ports are in progress, including PA-RISC and IA-64.

When did this happen? Here's a site that has a collection of kernels dating back to the very origin of Linux.

Interesting properties:

multitasking (scheduler)
multiuser (concept of a "user")
concept of "protection"
memory management
filesystem (everything is a file)
.....

Hmmm, which kernel? What are stable and development kernels?

The Rest

The Linux kernel is just the start of the story. Literally hundreds of other programs make a typical linux system. All of them written by developers that volunteer their time all over the world. A great part of the support programs that make a usable linux system were written by the GNU project (Gnu's not Unix) and the Free Software Foundation.

How?

Assembling a Linux system was not an easy task (download all components, compile, install and so on). Rather than that it's better to use a "distribution" (a prepackaged known to work collection of the programs that make up a working linux system).

Some popular distributions include: RedHat, Mandrake, SUSE, Debian and so on and so forth... Here at ccrma we're running RedHat 7.0 with all upgrades and with a custom 2.4.5 kernel with the low latency patches (rpm packages make it fairly easy to install and deinstall programs).

Security

with computers being more commonly connected to the internet permanently (dsl or cable modem) security considerations are important. Here's an interesting list of references that deal with securing a linux system.

Sound

A "sound driver" is the link between the software you're running and the hardware, there are currently three options I know off:

OSS Free: comes with the kernel (GPL)
OSS Commercial: $$, easy to install (binary distribution)
ALSA: a separate project that will probably be integrated with the kernel distribution in the future. Has a better (and still evolving) API than OSS