| 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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| 3 | "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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| 4 | <!ENTITY % general-entities SYSTEM "../../general.ent">
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| 5 | %general-entities;
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| 6 | ]>
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| 7 |
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| 8 | <sect1 id="pre-audience">
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| 9 | <?dbhtml filename="audience.html"?>
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| 10 |
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| 11 | <title>Audience</title>
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| 12 |
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| 13 | <para>There are many reasons why somebody would want to read this book.
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| 14 | The principal reason is to install a Linux system from the
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| 15 | source code. A question many people raise is, <quote>why go through all
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| 16 | the hassle of manually building a Linux system from scratch when you
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| 17 | can just download and install an existing one?</quote> That is a good
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| 18 | question and is the impetus for this section of the book.</para>
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| 19 |
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| 20 | <para>One important reason for LFS's existence is to help people learn
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| 21 | how a Linux system works from the inside out. Building an LFS system
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| 22 | helps demonstrate what makes Linux tick, and how things work together
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| 23 | and depend on each other. One of the best things that this learning
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| 24 | experience provides is the ability to customize Linux to your own
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| 25 | tastes and needs.</para>
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| 26 |
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| 27 | <para>A key benefit of LFS is that it allows users to have more control
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| 28 | over the system without relying on someone else's Linux implementation.
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| 29 | With LFS, <emphasis>you</emphasis> are in the driver's seat and dictate
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| 30 | every aspect of the system, such as the directory layout and bootscript
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| 31 | setup. You also dictate where, why, and how programs are installed.</para>
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| 32 |
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| 33 | <para>Another benefit of LFS is the ability to create a very compact
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| 34 | Linux system. When installing a regular distribution, one is often
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| 35 | forced to include several programs which are probably never used. These
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| 36 | programs waste disk space, or worse, CPU cycles. It is not
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| 37 | difficult to build an LFS system of less than 100 megabytes (MB), which
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| 38 | is substantially smaller than the majority of existing
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| 39 | installations. Does this still sound like a lot of space? A few of us
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| 40 | have been working on creating a very small embedded LFS system. We
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| 41 | successfully built a system that was specialized to run the Apache web
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| 42 | server with approximately 8MB of disk space used. Further stripping
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| 43 | could bring this down to 5 MB or less. Try that with a regular
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| 44 | distribution! This is only one of the many benefits of designing your
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| 45 | own Linux implementation.</para>
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| 46 |
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| 47 | <para>We could compare Linux distributions to a hamburger purchased at
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| 48 | a fast-food restaurant—you have no idea what might be in what you
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| 49 | are eating. LFS, on the other hand, does not give you a hamburger.
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| 50 | Rather, LFS provides the recipe to make the exact hamburger desired.
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| 51 | This allows users to review the recipe, omit unwanted ingredients, and
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| 52 | add your own ingredients to enhance the flavor of the burger. When you
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| 53 | are satisfied with the recipe, move on to preparing it. It can be made
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| 54 | to exact specifications—broil it, bake it, deep-fry it, or
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| 55 | barbecue it.</para>
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| 56 |
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| 57 | <para>Another analogy that we can use is that of comparing LFS with a
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| 58 | finished house. LFS provides the skeletal plan of a house, but it is up
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| 59 | to you to build it. LFS maintains the freedom to adjust plans throughout
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| 60 | the process, customizing it to the user's needs and preferences.</para>
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| 61 |
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| 62 | <para>An additional advantage of a custom built Linux system is security.
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| 63 | By compiling the entire system from source code, you are empowered to
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| 64 | audit everything and apply all the security patches desired. It is no
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| 65 | longer necessary to wait for somebody else to compile binary packages
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| 66 | that fix a security hole. Unless you examine the patch and implement it
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| 67 | yourself, you have no guarantee that the new binary package was built
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| 68 | correctly and adequately fixes the problem.</para>
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| 69 |
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| 70 | <para>The goal of Linux From Scratch is to build a complete and usable
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| 71 | foundation-level system. Readers who do not wish to build their own
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| 72 | Linux system from scratch may not benefit from the information in this
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| 73 | book. If you only want to know what happens while the computer boots,
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| 74 | we recommend the <quote>From Power Up To Bash Prompt</quote> HOWTO
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| 75 | located at <ulink url="http://axiom.anu.edu.au/~okeefe/p2b/"/> or on
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| 76 | The Linux Documentation Project's (TLDP) website at <ulink
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| 77 | url="http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html"/>.
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| 78 | The HOWTO builds a system which is similar to that of this book, but it
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| 79 | focuses strictly on creating a system capable of booting to a BASH prompt.
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| 80 | Consider your objective. If you wish to build a Linux system while
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| 81 | learning along the way, then this book is your best choice.</para>
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| 82 |
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| 83 | <para>There are too many good reasons to build your own LFS system to
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| 84 | list them all here. This section is only the tip of the iceberg. As
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| 85 | you continue in your LFS experience, you will find the power that
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| 86 | information and knowledge truly bring.</para>
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| 87 |
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| 88 | </sect1>
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