[PATCH] Update irange documentation

Also allow ':' as the range delimeter, and '/' as the
direction delimeter.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index f36fc46..4370c9f 100644
--- a/HOWTO
+++ b/HOWTO
@@ -179,7 +179,10 @@
 bool	Boolean. Usually parsed as an integer, however only defined for
 	true and false (1 and 0).
 irange	Integer range with postfix. Allows value range to be given, such
-	as 1024-4096. Also see siint.
+	as 1024-4096. A colon may also be used as the seperator, eg
+	1k:4k. If the option allows two sets of ranges, they can be
+	specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see
+	siint.
 
 With the above in mind, here follows the complete list of fio job
 parameters.