By the way the PDP-6 (and thus its dependent the PDP-10) was explicitly designed to be a "Lisp machine" -- a machine word was a cons and many fundamental lisp o

By the way the PDP-6 (and thus its dependent the PDP-10) was explicitly designed to be a "Lisp machine" -- a machine word was a cons and many fundamental lisp operations like car and cdr were single machine instructions.