diff --git a/developer/hooks/install.php b/developer/hooks/install.php
index 5197c83..5a6fe0e 100644
--- a/developer/hooks/install.php
+++ b/developer/hooks/install.php
@@ -247,6 +247,17 @@ function hook_install() {
  * the same directory as mymodule.module. Drupal core's updates are implemented
  * using the system module as a name and stored in database/updates.inc.
  *
+ * If your update task is potentially time-consuming, you'll need to implement a
+ * multipass update to avoid PHP timeouts. Multipass updates use the $sandbox
+ * parameter provided by the batch API (normally, $context['sandbox']) to store
+ * information between successive calls, and the $sandbox['#finished'] value to
+ * provide feedback regarding completion level.
+ *
+ * See the batch operations page for more information on how to use the batch API: http://drupal.org/node/180528
+ *
+ * @param $sandbox
+ *   Stores information for multipass updates. See above for more information.
+ *
  * @return An array with the results of the calls to update_sql(). An update
  *   function can force the current and all later updates for this
  *   module to abort by returning a $ret array with an element like: