Add an introduction to chapter 6 and 7

git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/cross2@11910 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/chapter06.xml

@@ -11,6 +11,7 @@
 
   <title>Cross Compiling Temporary Tools</title>
 
+  <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="introduction.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="m4.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="ncurses.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="bash.xml"/>

chapter06/introduction.xml

@@ -5,25 +5,26 @@
   %general-entities;
 ]>
 
-<sect1 id="ch-tools-introduction">
+<sect1 id="ch-tools-introduction-cross">
   <?dbhtml filename="introduction.html"?>
 
   <title>Introduction</title>
 
-  <para>This chapter shows how to build a minimal Linux system.
+  <para>This chapter shows how to cross-compile basic utilities using
-  This system will contain just enough tools to start constructing the final
+  the just built cross-toolchain. Those utilities are installed into
-  LFS system in <xref linkend="chapter-building-system"/> and allow a working
+  their final location, but cannot be used yet. Basic tasks still rely on
-  environment with more user convenience than a minimum environment would.</para>
+  the hosts tools. Nevertheless, the installed libraries are used when
+  linking.</para>
+
+  <para>Using the utilities will be possible in next chapter after entering
+  the <quote>chroot</quote> environment. But all the packages built in the
+  present chapter need themselves to be built. So we cannot be independent
+  on the build system yet.</para>
+
+  <para>Once again, let us recall that improper setting of <envar>LFS</envar>
+  together with building as root, may render your computer unusable.
+  This whole chapter must be done as user <systemitem
+  class="username">lfs</systemitem>, with the enviroment as described in
+  <xref linkend="ch-preps-settingenviron"/>.</para>
 
-  <para>There are two steps in building this minimal system. The first step
-  is to build a new and host-independent toolchain (compiler, assembler,
-  linker, libraries, and a few useful utilities).  The second step uses this
-  toolchain to build the other essential tools.</para>
-<!--
-  <para>The files compiled in this chapter will be installed under the
-  <filename class="directory">$LFS</filename> directory to keep them
-  separate from the files installed in the next chapter and the host
-  production directories. Since the packages compiled here are temporary,
-  we do not want them to pollute the soon-to-be LFS system.</para>
--->
 </sect1>

chapter07/chapter07.xml

@@ -11,6 +11,7 @@
 
   <title>Entering Chroot and Building Additional Tools</title>
 
+  <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="introduction.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="changingowner.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="kernfs.xml"/>
   <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="chroot.xml"/>

chapter07/introduction.xml

@@ -5,25 +5,33 @@
   %general-entities;
 ]>
 
-<sect1 id="ch-tools-introduction">
+<sect1 id="ch-tools-introduction-chroot">
   <?dbhtml filename="introduction.html"?>
 
   <title>Introduction</title>
 
-  <para>This chapter shows how to build a minimal Linux system.
+  <para>This chapter shows how to build the last missing bits of the
-  This system will contain just enough tools to start constructing the final
+  temporary system: first, the tools needed by the build machinery of
-  LFS system in <xref linkend="chapter-building-system"/> and allow a working
+  various packages, then three packages needed to run tests.
-  environment with more user convenience than a minimum environment would.</para>
+  Now that all circular dependencies have been resolved,
+  we can use a <quote>chroot</quote> environment, completely isolated
+  from the computer used for the build, except for the running kernel.</para>
+
+  <para>For proper operation of the isolated environment, some communication
+  with the running kernel must be established. This is done through the
+  so-called <emphasis>Virtual Kernel File Systems</emphasis>, which must be
+  mounted when entering the chroot environment. You may want to check
+  that they are mounted by issuing <command>ls $LFS/dev</command>,
+  <command>ls $LFS/proc</command>, or <command>ls $LFS/sys</command>.
+  Note that mounting the virtual kernel file systems must be done
+  <emphasis>each time you want to enter the chroot
+  environment</emphasis>.</para>
+
+  <para>Until <xref linkend="ch-tools-chroot"/>, the commands must be
+  run as <systemitem class="username">root</systemitem>, with the
+  <envar>LFS</envar> variable set. After entering chroot, all commands
+  are run as root, fortunately without access to the OS of the computer
+  you build LFS on. Be careful anyway, as it is easy to destroy the whole
+  LFS system with badly formed commands.</para>
 
-  <para>There are two steps in building this minimal system. The first step
-  is to build a new and host-independent toolchain (compiler, assembler,
-  linker, libraries, and a few useful utilities).  The second step uses this
-  toolchain to build the other essential tools.</para>
-<!--
-  <para>The files compiled in this chapter will be installed under the
-  <filename class="directory">$LFS</filename> directory to keep them
-  separate from the files installed in the next chapter and the host
-  production directories. Since the packages compiled here are temporary,
-  we do not want them to pollute the soon-to-be LFS system.</para>
--->
 </sect1>