diff --git a/apps/tagcache.c b/apps/tagcache.c
index 280f45d695..f903de5190 100644
--- a/apps/tagcache.c
+++ b/apps/tagcache.c
@@ -17,6 +17,42 @@
  *
  ****************************************************************************/
 
+/*
+ *                    TagCache API
+ * 
+ *       ----------x---------x------------------x-----
+ *                 |         |                  |              External
+ * +---------------x-------+ |       TagCache   |              Libraries
+ * | Modification routines | |         Core     |           
+ * +-x---------x-----------+ |                  |           
+ *   | (R/W)   |             |                  |           |
+ *   |  +------x-------------x-+  +-------------x-----+     |
+ *   |  |                      x==x Filters & clauses |     |
+ *   |  | Search routines      |  +-------------------+     |
+ *   |  |                      x============================x DirCache
+ *   |  +-x--------------------+                            | (optional)
+ *   |    | (R)                                             |
+ *   |    | +-------------------------------+  +---------+  |
+ *   |    | | DB Commit (sort,unique,index) |  |         |  |
+ *   |    | +-x--------------------------x--+  | Control |  |
+ *   |    |   | (R/W)                    | (R) | Thread  |  |
+ *   |    |   | +----------------------+ |     |         |  |
+ *   |    |   | | TagCache DB Builder  | |     +---------+  |
+ *   |    |   | +-x-------------x------+ |                  |
+ *   |    |   |   | (R)         | (W)    |                  |
+ *   |    |   |   |          +--x--------x---------+        |
+ *   |    |   |   |          | Temporary Commit DB |        |
+ *   |    |   |   |          +---------------------+        |
+ * +-x----x---x---x--+                                      |
+ * | TagCache RAM DB x==\(W) +-----------------+            |
+ * +-x----x---x---x--+   \===x                 |            |
+ *   |    |   |   |      (R) |  Ram DB Loader  x============x DirCache
+ * +-x----x---x---x---+   /==x                 |            | (optional)
+ * | Tagcache Disk DB x==/   +-----------------+            |  
+ * +------------------+                                     |
+ * 
+ */
+
 #include <stdio.h>
 #include "thread.h"
 #include "kernel.h"