Chapter 6 - Clarify remaining PTY issues.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@2893 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

1 files changed, 40 insertions, 31 deletions

diff --git a/chapter06/mountproc.xml b/chapter06/mountproc.xml
index cfe40f562..380a2ec5c 100644
--- a/chapter06/mountproc.xml
+++ b/chapter06/mountproc.xml
@@ -2,33 +2,22 @@
 <title>Mounting the proc and devpts file systems</title>
 <?dbhtml filename="proc.html" dir="chapter06"?>
 
-<para>In order for certain programs to function properly, the proc and devpts
-file systems must be available within the chroot environment.
-As a file system can be mounted as many times and in as many places
-as you like, it's not a problem that the these file systems are already
-mounted on your host system -- especially so because they are virtual 
-file systems.</para>
+<para>In order for certain programs to function properly, the
+<emphasis>proc</emphasis> and <emphasis>devpts</emphasis> file systems must be
+available within the chroot environment. A file system can be mounted as many
+times and in as many places as you like, thus it's not a problem that the these
+file systems are already mounted on your host system -- especially so because
+they are virtual file systems.</para>
 
-<para>The proc file system is mounted under
-<filename class="directory">/proc</filename> by running the
-following command:</para>
+<para>The <emphasis>proc</emphasis> file system is the process information
+pseudo-filesystem that the kernel uses to provide status information about the
+status of the system.</para>
 
-<para><screen><userinput>mount proc /proc -t proc</userinput></screen></para>
-
-<para>The devpts file system is mounted to <filename class="directory">/dev/pts
-</filename> by running:</para>
-
-<para><screen><userinput>mount devpts /dev/pts -t devpts</userinput></screen>
-</para>
-
-<para>Should this command fail with an error to the effect of:</para>
-
-<blockquote><screen>filesystem devpts not supported by kernel</screen></blockquote>
+<para>The proc file system is mounted on
+<filename class="directory">/proc</filename> by running the following
+command:</para>
 
-<para>This most likely means that your host system uses devfs, and does not
-have the necessary support for devpts in the kernel.  To work around this
-problem, we will place the host's devfs system on top of the new /dev
-structure later, in the section where we run the MAKEDEV script.</para>
+<para><screen><userinput>mount proc /proc -t proc</userinput></screen></para>
 
 <para>You might get warning messages from the mount command, such as
 these:</para>
@@ -40,14 +29,34 @@ not enough memory</screen></blockquote>
 isn't installed completely yet and some files are missing. The mount itself
 will be successful and that's all we care about at this point.</para>
 
-<para>The last error (not enough memory) doesn't always show up. It depends
-on your system configuration (such as the host system's Glibc version that was
-used to compile the mount program with).</para>
+<para>The <emphasis>devpts</emphasis> file system was mentioned earlier and is
+now the most common way for pseudo terminals (PTYs) to be implemented.</para>
+
+<para>The devpts file system is mounted on 
+<filename class="directory">/dev/pts</filename> by running:</para>
+
+<para><screen><userinput>mount devpts /dev/pts -t devpts</userinput></screen></para>
+
+<para>Should this command fail with an error to the effect of:</para>
+
+<blockquote><screen>filesystem devpts not supported by kernel</screen></blockquote>
 
-<para>Remember, if for any reason you stop working on your LFS, and
-start again later, it's important to check that these filesystems are still
-mounted inside the chroot environment. Otherwise, some programs might
-end up compiled incorrectly.</para>
+<para>The most likely cause is that your host system's kernel was compiled
+without support for the devpts file system. You can check which file systems
+your kernel supports by peeking into its internals with a command such as
+<userinput>cat /proc/filesystems</userinput>. If for some reason, devpts is
+listed there but the mount still doesn't work, check instead for a different
+file system variety called <emphasis>devfs</emphasis>. If devfs is listed then
+we'll be able to work around the problem by mounting the host's devfs file
+system on top of the new <filename>/dev</filename> structure which we'll create
+later on in the "Creating devices (Makedev)" section. If devfs was not listed,
+do not worry because there is yet a third way to get PTYs working inside the
+chroot environment. We'll cover this shortly in the aforementioned Makedev
+section.</para>
+
+<para>Remember, if for any reason you stop working on your LFS, and start again
+later, it's important to check that these filesystems are still mounted inside
+the chroot environment, otherwise problems are likely to occur.</para>
 
 </sect1>