add a disclaimer to the retrospective

Author: steveloughran

software_engineering/retrospective.md

@@ -1,4 +1,10 @@
 
+%% I had in mind some somewhat tongue-in-cheek doc on the history of Sw engineering here, trying to refer
+%% to the really good things, all usng times relative to the 1970 epoch.
+%% got distracted and I've forgotten what I was gong to say.
+%% do buy a copy of that MIT System 360 book -it makes you realise what the Mythical Man Month team
+%% were working with https://mitpress.mit.edu/9780262517201/ibms-360-and-early-370-systems/
+
 Time began on January 1, 1970, Unix Epoch
 
 From a software engineering perspective there is very little of relevance before then.