1.1. Purpose of this document
This document is intended to help Linux and Internet users who are
learning by doing. While this is a great way to acquire specific skills,
sometimes it leaves peculiar gaps in one's knowledge of the basics — gaps
which can make it hard to think creatively or troubleshoot effectively,
from lack of a good mental model of what is really going on.
I'll try to describe in clear, simple language how it all works. The
presentation will be tuned for people using Unix or Linux on PC-class
hardware. Nevertheless, I'll usually refer simply to ‘Unix’
here, as most of what I will describe is constant across platforms and
across Unix variants.
I'm going to assume you're using an Intel PC. The details differ
slightly if you're running an Alpha or PowerPC or some other Unix box, but
the basic concepts are the same.
I won't repeat things, so you'll have to pay attention, but that
also means you'll learn from every word you read. It's a good idea to just
skim when you first read this; you should come back and reread it a few
times after you've digested what you have learned.
This is an evolving document. I intend to keep adding sections in
response to user feedback, so you should come back and review it
periodically.
1.3. Feedback and corrections
If you have questions or comments about this document, please feel
free to mail Eric S. Raymond, at
esr at thyrsus.com. I welcome any suggestions or criticisms. I
especially welcome hyperlinks to more detailed explanations of individual
concepts. If you find a mistake with this document, please let me know so
I can correct it in the next version. Thanks.
Free eBook: 
