Index: head/en_US.ISO8859-1/books/handbook/disks/chapter.xml
===================================================================
--- head/en_US.ISO8859-1/books/handbook/disks/chapter.xml
+++ head/en_US.ISO8859-1/books/handbook/disks/chapter.xml
@@ -1996,9 +1996,10 @@
 	on <filename>/mnt</filename>:</para>
 
       <screen>&prompt.root; <userinput>mdconfig -f <replaceable>diskimage.iso</replaceable> -u <replaceable>0</replaceable></userinput>
-&prompt.root; <userinput>mount /dev/md<replaceable>0</replaceable> <replaceable>/mnt</replaceable></userinput></screen>
+&prompt.root; <userinput>mount -t cd9660 /dev/md<replaceable>0</replaceable> <replaceable>/mnt</replaceable></userinput></screen>
 
-      <para>If a unit number is not specified with
+      <para>Notice that <option>-t cd9660</option> was used to mount
+	an ISO format.  If a unit number is not specified with
 	<option>-u</option>, <command>mdconfig</command> will
 	automatically allocate an unused memory device and output
 	the name of the allocated unit, such as