source: BOOK/prologue/common/audience.xml@ bc610664

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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 CLFS's existence is to help people learn
  how a Linux system works from the inside out. Building an CLFS 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 CLFS is that it allows users to have more control
  over the system without relying on someone else's Linux implementation.
  With CLFS, <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 CLFS 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 CLFS 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 CLFS 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. CLFS, on the other hand, does not give you a hamburger.
  Rather, CLFS 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 CLFS with a
  finished house. CLFS provides the skeletal plan of a house, but it is up
  to you to build it. CLFS 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 CLFS system to
  list them all here. This section is only the tip of the iceberg. As
  you continue in your CLFS experience, you will find the power that
  information and knowledge truly bring.</para>

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