Linux for Dummies

The primary job of an operating system is to load software (computer pro-
grams) from the hard drive (or other permanent storage) into the memory
and get the CPU to run those programs. Everything you do with your com-
puter is possible because of the operating system, so if the operating system
somehow messes up, the whole system freezes. You know how infuriating it
is when your favorite operating system -- maybe even the one that came
with your PC -- suddenly calls it quits just as you were about to click the
Send button after composing that long e-mail to your friend. You try the
three-finger salute (pressing Ctrl+Alt+Delete), but nothing happens. Then it's
time for the Reset button (provided your computer's builders were wise
enough to include one). Luckily, that sort of thing almost never happens
with Linux -- it has a reputation for being a very reliable operating system.
In technical mumbo jumbo, Linux is a multiuser, multitasking operating
system. All this means is that Linux enables multiple users to log in, and
Linux can run more than one program at the same time. Nearly all operating
systems are multiuser and multitasking these days, but when Linux first
started in 1994, multiuser and multitasking were big selling points.
Linux distributions
A Linux distribution consists of the Linux kernel (the operating system) and
a collection of applications, together with an easy-to-use installation pro-
gram. By the way, most people just say Linux to refer to a specific Linux
distribution.
You find many Linux distributions, and each includes the standard Linux
operating system and the following major packages:
Does Linux really run on any computer?
Linux runs on many different types of computer
systems -- and it does seem able to run on
nearly any type of computer. Linus Torvalds and
other programmers originally developed Linux
for the Intel 80x86 (and compatible) line of
processors. Nowadays, Linux is also available
for systems based on other processors -- such
as those with AMD's 64-bit AMD64 processors,
the Motorola 68000 family, Alpha AXPs, Sun
SPARCs and UltraSPARCs, Hewlett-Packard's
HP PA-RISC, the PowerPC and PowerPC64
processors, and the MIPS R4x00 and R5x00.
More recently, IBM has released its own ver-
sion of Linux for its S/390 and zSeries main-
frames. This book covers Linux for Intel 80x86
and Pentium processors. (These are known as
the IA32 architecture processors, or i386,
because they support the instruction set of the
80386 processor.)