More grammatical and typo fixes. While I'm here, add a few notes to

various parts to make things more clear to the reader.

Submitted by:	John Murphy <jfm@blueyonder.co.uk> on -doc

en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml

@@ -1,7 +1,7 @@
 <!--
      The FreeBSD Documentation Project
 
-     $FreeBSD: doc/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml,v 1.54 2001/07/30 17:18:52 murray Exp $
+     $FreeBSD: doc/en_US.ISO8859-1/books/handbook/kernelconfig/chapter.sgml,v 1.55 2001/08/02 00:47:33 nik Exp $
 -->
 
 <chapter id="kernelconfig">
@@ -443,8 +443,8 @@ cpu          I686_CPU</programlisting>
       You may have multiple instances of the CPU line (i.e., you are not
       sure whether you should use <literal>I586_CPU</literal> or
       <literal>I686_CPU</literal>), however, for a custom kernel, it is
-      best to specify only the CPU you have.  If you are unsure which type
+      best to specify only the CPU you have.  If you are unsure of your CPU type,
-      your CPU use, you can use the <command>dmesg</command> command to
+      you can use the <command>dmesg</command> command to
       view your boot up messages.</para>
     <indexterm>
       <primary>kernel options</primary>
@@ -1042,7 +1042,7 @@ pseudo-device   loop          # Network loopback</programlisting>
 
     <programlisting>pseudo-device   tun           # Packet tunnel.</programlisting>
 
-    <para>This is used by the userland PPP software.  The
+    <para>This is used by the userland PPP software.  A
       <replaceable>number</replaceable> after <literal>tun</literal>
       specifies the number of simultaneous PPP sessions to support.  See
       the <link linkend="userppp">PPP</link> section of this book for more
@@ -1055,8 +1055,8 @@ pseudo-device   pty           # Pseudo-ttys (telnet etc)</programlisting>
       It is used by incoming <command>telnet</command> and
       <command>rlogin</command> sessions,
       <application>xterm</application>, and some other applications such
-      as <application>emacs</application>.  The
+      as <application>emacs</application>.  A
-      <replaceable>number</replaceable> indicates the number of
+      <replaceable>number</replaceable> after <literal>pty</literal> indicates the number of
       <literal>pty</literal>s to create.  If you need more than the
       default of 16 simultaneous <application>xterm</application> windows
       and/or remote logins, be sure to increase this number accordingly,
@@ -1087,6 +1087,13 @@ pseudo-device   bpf           # Berkeley packet filter</programlisting>
       can be captured to disk and or examined with the &man.tcpdump.1;
       program.</para>
 
+    <note>
+      <para>The <literal>bpf pseudo-device</literal> is also used by
+	&man.dhclient.8; to obtain the IP address of the default router
+	(gateway) and so on.  If you use DHCP, leave this
+	uncommented.</para>
+    </note>
+
     <programlisting># USB support
 #device         uhci          # UHCI PCI-&gt;USB interface
 #device         ohci          # OHCI PCI-&gt;USB interface
@@ -1255,6 +1262,14 @@ pseudo-device   bpf           # Berkeley packet filter</programlisting>
 
 	    <screen>&prompt.root; <userinput>chflags noschg /kernel</userinput></screen>
 
+	    <para>If you find you cannot do this, you are probably running
+	      at a &man.securelevel.8; greater than zero.  Edit
+	      <literal>kern_securelevel</literal> in
+	      <filename>/etc/rc.conf</filename> and set it to
+	      <literal>-1</literal>, then reboot.  You can change it back
+	      to its previous setting when you are happy with your new
+	      kernel.</para>
+
 	    <para>And, if you want to <quote>lock</quote> your new kernel
 	      into place, or any file for that matter, so that it cannot
 	      be moved or tampered with:</para>