update docstrings / comments

diff --git a/src/add/iocontrol.py b/src/add/iocontrol.py
index 02e24780ef54529454cab818b01d0a4b85585754..a4450c80e7af3ad2855fa21ad413a6f358df65f0 100644 (file)
--- a/src/add/iocontrol.py
+++ b/src/add/iocontrol.py
@@ -9,6 +9,14 @@
 
     stage requires compliance with a strict API that may be
     implemented in several means, including as a static class.
+
+    Stage Blocks really must be combinatorial blocks.  It would be ok
+    to have input come in from sync'd sources (clock-driven) however by
+    doing so they would no longer be deterministic, and chaining such
+    blocks with such side-effects together could result in unexpected,
+    unpredictable, unreproduceable behaviour.
+    So generally to be avoided, then unless you know what you are doing.
+
     the methods of a stage instance must be as follows:
 
     * ispec() - Input data format specification