lfs-book/prologue/audience.xml

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<sect1 id="pre-audience">
  <?dbhtml filename="audience.html"?>

  <title>Audience</title>

  <para>There are many reasons why somebody would want to read this book.
  The principal reason is to install a Linux system from the source code.
  A question many people raise is, <quote>why go through all the hassle of
  manually building a Linux system from scratch when you can just download
  and install an existing one?</quote> That is a good question and is the
  impetus for this section of the book.</para>

  <para>One important reason for LFS's existence is to help people learn
  how a Linux system works from the inside out. Building an LFS system
  helps demonstrate what makes Linux tick, and how things work together
  and depend on each other. One of the best things that this learning
  experience provides is the ability to customize Linux to your own tastes
  and needs.</para>

  <para>A key benefit of LFS is that it allows users to have more control
  over the system without relying on someone else's Linux implementation.
  With LFS, <emphasis>you</emphasis> are in the driver's seat and dictate
  every aspect of the system, such as the directory layout and bootscript
  setup. You also dictate where, why, and how programs are installed.</para>

  <para>Another benefit of LFS is the ability to create a very compact Linux
  system. When installing a regular distribution, one is often forced to
  include several programs which are probably never used. These programs
  waste disk space, or worse, CPU cycles. It is not difficult to build an
  LFS system of less than 100 megabytes (MB), which is substantially smaller
  than the majority of existing installations. Does this still sound like a
  lot of space? A few of us have been working on creating a very small
  embedded LFS system. We successfully built a system that was specialized
  to run the Apache web server with approximately 8MB of disk space used.
  Further stripping could bring this down to 5 MB or less. Try that with a
  regular distribution! This is only one of the many benefits of designing
  your own Linux implementation.</para>

  <para>We could compare Linux distributions to a hamburger purchased at a
  fast-food restaurant&mdash;you have no idea what might be in what you are
  eating. LFS, on the other hand, does not give you a hamburger. Rather,
  LFS provides the recipe to make the exact hamburger desired. This allows
  users to review the recipe, omit unwanted ingredients, and add your own
  ingredients to enhance the flavor of the burger. When you are satisfied
  with the recipe, move on to preparing it. It can be made to exact
  specifications&mdash;broil it, bake it, deep-fry it, or barbecue it.</para>

  <para>Another analogy that we can use is that of comparing LFS with a
  finished house. LFS provides the skeletal plan of a house, but it is up
  to you to build it. LFS maintains the freedom to adjust plans throughout
  the process, customizing it to the user's needs and preferences.</para>

  <para>An additional advantage of a custom built Linux system is security.
  By compiling the entire system from source code, you are empowered to audit
  everything and apply all the security patches desired. It is no longer
  necessary to wait for somebody else to compile binary packages that fix a
  security hole. Unless you examine the patch and implement it yourself, you
  have no guarantee that the new binary package was built correctly and
  adequately fixes the problem.</para>

  <para>The goal of Linux From Scratch is to build a complete and usable
  foundation-level system. Readers who do not wish to build their own Linux
  system from scratch may not benefit from the information in this book. If
  you only want to know what happens while the computer boots, we recommend
  the <quote>From Power Up To Bash Prompt</quote> HOWTO located at
  <ulink url="http://axiom.anu.edu.au/~okeefe/p2b/"/> or on The Linux
  Documentation Project's (TLDP) website at <ulink
  url="http://www.tldp.org/HOWTO/From-PowerUp-To-Bash-Prompt-HOWTO.html"/>.
  The HOWTO builds a system which is similar to that of this book, but it
  focuses strictly on creating a system capable of booting to a BASH prompt.
  Consider your objective. If you wish to build a Linux system while learning
  along the way, then this book is your best choice.</para>

  <para>There are too many good reasons to build your own LFS system to
  list them all here. This section is only the tip of the iceberg. As
  you continue in your LFS experience, you will find the power that
  information and knowledge truly bring.</para>

</sect1>