Alan Turing: The Enigma (60 page)

Colonel Morcorm, Mr Morcom and Christopher on holiday, summer 1929.

George Maclure, Peter Hogg and Alan setting out on their hike from Godalming, surrey Easter 1931 (see page 58).

Alan Turing in a Guildford street, a chance snapshot taken in 1934.

A brushed-up Alan with his father and mother and a family friend (right) outside 8 Ennismore Avenue in 1938.

Boy and buoys at Bosham, August 1939 (see page 158). From the front: Alan, Bob, Karl and Fred Clayton.

The naval Enigma machine with its lid raised to show the four rotors.

The Colossus in operation at Bletchley Park, 1944–5, showing the rapid punched tape input mechanism.

In Contrast the complete Delilah terminal fitted easily on to a table top (note the scale).

The key unit, with lid removed to show both rotors and multivibrators.

Robin Gandy in Summer 1953, on holiday in France.

A sporting second in a three-mile race: possibly the event of 26 December 1946 (see page 353).

The pilot ACE computer, on show at the NPL in November 1950. Jim Wilkinson is the righthand figure.

The prototype Manchester computer. The six racks shown are essentially those of the ‘baby machine’ which ran its first program in June 1948; by June 1949 when this photograph was taken the machine had roughly doubled in size.