Index: opal/mca/base/mca_base_components_open.c
===================================================================
--- opal/mca/base/mca_base_components_open.c	(revision 18380)
+++ opal/mca/base/mca_base_components_open.c	(working copy)
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
+ * Copyright (c) 2004-2008 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
  * Copyright (c) 2004-2007 The University of Tennessee and The University
@@ -81,6 +81,7 @@
     int param_verbose = -1;
     int param_type = -1;
     int verbose_level;
+    int c_itr = 0;
     char *str;
     bool include_mode;
 #if (OPAL_ENABLE_FT == 1) && (OPAL_ENABLE_FT_CR == 1)
@@ -123,6 +124,24 @@
         return ret;
     }

+    /* Check for MCA-NULL - Open nothing */
+    for(c_itr = 0; c_itr < opal_argv_count(requested_component_names); ++c_itr) {
+        if ( 0 == strncmp(requested_component_names[c_itr], "MCA-NULL", strlen("MCA-NULL")) ) {
+            opal_output_verbose(10, output_id, 
+                                "mca: base: components_open: Not opening any %s components. MCA-NULL keyword specified.",
+                                type_name);
+            /* Make sure to construct the available list so upper level can
+             * use it as an empty list */
+            OBJ_CONSTRUCT(components_available, opal_list_t);
+
+            if (NULL != requested_component_names) {
+                opal_argv_free(requested_component_names);
+            }
+
+            return OPAL_SUCCESS;
+        }
+    }
+
     /* Find and load requested components */
     if (OPAL_SUCCESS != 
         mca_base_component_find(NULL, type_name, static_components,