source: BOOK/introduction/common/how.xml@ 3769a71

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<sect1 id="ch-intro-how">
  <?dbhtml filename="how.html"?>

  <title>How to Build an LFS System</title>

  <para>The LFS system will be built by using a previously installed
  Linux distribution (such as Debian, Mandrake, Red Hat, or SuSE). This
  existing Linux system (the host) will be used as a starting point to
  provide necessary programs, including a compiler, linker, and shell,
  to build the new system. Select the <quote>development</quote> option
  during the distribution installation to be able to access these
  tools.</para>

  <para>As an alternative to installing an entire separate distribution
  onto your machine, and if your host machine is x86 based, you may wish to
  use the Linux From Scratch LiveCD. The CD works well as a host system,
  providing all the tools you need to successfully follow the instructions
  in this book. Additionally, it contains all the source packages, patches
  and a copy of this book. So once you have the CD, no network connection
  or additional downloads are necessary. For more information about the
  LFS LiveCD or to download a copy, visit <ulink url="&livecd-root;"/></para>

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  <para>THE TEXT BELOW NEEDS TO BE REWRITTEN</para>

  <para><xref linkend="chapter-partitioning"/> of this book describes how
  to create a new Linux native partition and file system, the place
  where the new LFS system will be compiled and installed. <xref
  linkend="chapter-getting-materials"/> explains which packages and
  patches need to be downloaded to build an LFS system and how to store
  them on the new file system. <xref linkend="chapter-final-preps"/>
  discusses the setup for an appropriate working environment. Please read
  <xref linkend="chapter-final-preps"/> carefully as it explains several
  important issues the developer should be aware of before beginning to
  work through <xref linkend="chapter-cross-tools"/> and
  beyond.</para>

  <para><xref linkend="chapter-temp-system"/> explains the
  installation of a number of packages that will form the basic
  development suite (or toolchain) which is used to build the actual
  system in <xref linkend="chapter-building-system"/>. Some of these
  packages are needed to resolve circular dependencies&mdash;for example,
  to compile a compiler, you need a compiler.</para>

  <para><xref linkend="chapter-temp-system"/> also shows the user
  how to build a first pass of the toolchain, including Binutils and GCC
  (first pass basically means these two core packages will be re-installed
  a second time). The next step is to build Glibc, the C library. Glibc
  will be compiled by the toolchain programs built in the first pass. Then,
  a second pass of the toolchain will be built. This time, the toolchain
  will be dynamically linked against the newly built Glibc. The remaining
  <xref linkend="chapter-temp-system"/> packages are built using this
  second pass toolchain. When this is done, the LFS installation process
  will no longer depend on the host distribution, with the exception of the
  running kernel. </para>

  <para>This effort to isolate the new system from the host distribution
  may seem excessive, but a full technical explanation is provided at the
  beginning of <xref linkend="chapter-temp-system"/>.</para>

  <para>In <xref linkend="chapter-building-system"/>, the full LFS system is
  built. The <command>chroot</command> (change root) program is used to enter
  a virtual environment and start a new shell whose root directory will be set
  to the LFS partition. This is very similar to rebooting and instructing the
  kernel to mount the LFS partition as the root partition. The system does not
  actually reboot, but instead <command>chroot</command>'s because creating a
  bootable system requires additional work which is not necessary just yet.
  The major advantage is that <quote>chrooting</quote> allows the builder to
  continue using the host while LFS is being built. While waiting for package
  compilation to complete, a user can switch to a different virtual console
  (VC) or X desktop and continue using the computer as normal.</para>

  <para>To finish the installation, the LFS-Bootscripts are set up in <xref
  linkend="chapter-bootscripts"/>, and the kernel and boot loader are set
  up in <xref linkend="chapter-bootable"/>. <xref
  linkend="chapter-finalizing"/> contains information on furthering the
  LFS experience beyond this book.  After the steps in this book have
  been implemented, the computer will be ready to reboot into the new
  LFS system.</para>
  <!-- -->

  <para>This is the process in a nutshell. Detailed information on each
  step is discussed in the following chapters and package descriptions.
  Items that may seem complicated will be clarified, and everything will
  fall into place as the reader embarks on the LFS adventure.</para>

</sect1>