Added misc notes

doc/NOTES.md

@@ -0,0 +1,24 @@
+Blocks
+======
+
+Chassis is 2m high, and contains XX units in two columns
+
+Items (chassis mount)
+=====================
+* Terminal is 2u
+* cpu is 1u (includes 32k mem, console controller)
+* tape is 2u
+* disk is 1u
+* memory module is 1u/32k
+
+Supported hardware
+==================
+
+4 RL disks
+4 TM magtapes
+?? serial multiplexer
+
+Cabling
+=======
+
+unibus only extends between connected chassis (l/r)