docs: add not to dirnode.txt that it is obsolete

diff --git a/docs/dirnodes.txt b/docs/dirnodes.txt
index 809a4c5ff5635e885024ef18bbe6f23e704cd26a..d54ee2fb64c21c0ca98aee30cd0b4eefb1e12842 100644 (file)
--- a/docs/dirnodes.txt
+++ b/docs/dirnodes.txt
@@ -1,3 +1,9 @@
+NOTE: this file starts by explaining old-style (no longer used) centralized
+directories, but it also has useful discussion of security, efficiency, and
+usage, so I'm not removing it from the source code distribution just yet.
+Hopefully its contents which are still relevant will be reworked into a new
+document.
+
 
 = Tahoe Directory Nodes =