The entire CPU slides out on rails for easy access to the boards.


The CPU consists of a large number of a couple of different very simple logic boards.


This is a typical board:


The boards are keyed with notches so each socket only accepts the correct kind of board.


The Ferranti delay lines are piggybacked on a board to fit into the backplane. This is one of the "short" delay lines. The "long" delay lines are physically much larger.