--- doc/src/sgml/runtime.sgml.orig	2008-10-18 00:05:37.000000000 -0500
+++ doc/src/sgml/runtime.sgml	2008-10-18 00:08:37.000000000 -0500
@@ -401,6 +401,15 @@
     </para>
 
     <para>
+    You can also get this error if you try to start two servers on the
+    same machine, on the same port, even if you specify different
+    listen_address values.  In order for that configuration to work,
+    you'll need to run the servers under different userids, which will
+    cause <productname>PostgreSQL</productname> to use different
+    shared memory keys.
+	</para>
+
+    <para>
      An error like
 <screen>
 FATAL:  could not create semaphores: No space left on device