Added the description of frcode, code, and bigram.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@593 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

appendixa/findutils-desc.xml

@@ -57,5 +57,32 @@ command on the list.
 
 </sect3>
 
+<sect3><title>frcode</title>
+
+<para>
+updatedb runs a program called frcode to compress the list of file names
+using front-compression, which reduces the database size by a factor of
+4 to 5.
+</para>
+
+</sect3>
+
+<sect3><title>code</title>
+
+<para>
+code is the ancestor of frcode. It was used in older-style locate databases.
+</para>
+
+</sect3>
+
+<sect3><title>bigram</title>
+	
+<para>
+bigram is used together with code to produce older-style locate databases. To
+learn more about these last three programs, read the locatedb.5 manual page.
+</para>
+
+</sect3>
+
 </sect2>