Nimrod

The idea: John Bennett and a machine built only to play

In late 1950, John Bennett, an Australian employee of Ferranti who had recently completed a PhD at Cambridge, proposed building a computer to play Nim, an ancient mathematical game in which players alternately remove one or more objects from several piles. According to Wikipedia, Bennett's idea was reportedly inspired by the Nimatron, a machine built by relay engineers Gerald Tawney and Willard Derr at Westinghouse from a concept by Edward Condon, and displayed between April and October 1940 at the New York World's Fair. Unlike the electromechanical Nimatron, Nimrod was built as a digital computer based on vacuum tubes. Engineer Raymond Stuart-Williams turned Bennett's concept into a working machine: construction began on 1 December 1950 and was completed on 12 April 1951. According to Grace's Guide to British Industrial History, that same year Ferranti also delivered its first Ferranti Mark 1 to Manchester University — in other words, Nimrod came from an established engineering firm that was just then entering the general-purpose computer business. According to Wikipedia, although Bennett proposed a game, his goal was "to show off the computer's ability to do mathematical calculations," since Nim is based on mathematical principles.

What was actually inside the box

According to Wikipedia, Nimrod measured roughly 3.7 meters wide, 2.7 meters deep and 1.5 meters tall — the size of several large cabinets. Most of that volume had nothing to do with the actual computation: the vacuum tubes and the display bulbs that showed the public the machine's moves took up nearly all the space, and according to Wikipedia the computer itself occupied no more than 2% of the total volume. The machine was built so its operating speed could be slowed down, so that a presenter at the exhibition could explain what it was doing at each step. According to Wikipedia, BBC radio journalist Paul Jennings described the machine as a "tremendous gray refrigerator," and claimed that all the festival-goers "came to a standstill" on reaching it.

How to play against Nimrod

Each turn, a player removed one or more objects from a single pile, and according to Wikipedia Nimrod could play both the "traditional" and the "reverse" form of Nim: in one, the player who takes the last object wins; in the other, that player loses. The player pressed buttons on a raised stand, corresponding to bulbs representing the objects in the piles. Nimrod calculated its response and displayed it on a separate panel of lights, while signs announced whose turn it was and who had won. According to Wikipedia, Ferranti also published a one-shilling-sixpence pamphlet titled Faster Than Thought: The Ferranti Nimrod Digital Computer, explaining to visitors how the machine worked.

The 1951 Festival of Britain: the public wanted to play, not to be impressed by engineering

The Festival of Britain was a national exhibition that opened in May 1951, funded mostly by the government, meant to give the British public a sense of recovery and progress after the Second World War and to promote British science and technology. Nimrod was shown at the festival's Exhibition of Science in South Kensington, London, where it was presented on 5 May 1951. Ferranti advertised Nimrod as "faster than thought" and an "electronic brain," intending to demonstrate its design and programming skills, not to entertain. In practice, according to Wikipedia, exhibition visitors were far more interested in the game itself than in the technology behind it — and according to the same source, among those reported to have played against the machine was the computer scientist Alan Turing. Bennett himself later said, according to Wikipedia, that "most of the public were quite happy to gawk at the flashing lights and be impressed." Ferranti's own pamphlet anticipated the objection: "It may appear that, in trying to make machines play games, we are wasting our time." It went straight on to answer that this was not true, because the theory of games is extremely complex, and a machine that can play a complex game can also be programmed to carry out very complex practical problems.

After London: Berlin, Toronto, and dismantling

After the festival, Ferranti took Nimrod to the Berlin Industrial Show, where it was displayed for about three weeks in October 1951, and according to Wikipedia it was also visited by West German economics minister Ludwig Erhard, who later became chancellor of Germany. It was then briefly shown in Toronto, and afterward dismantled. Ferranti did not follow it up with any further games, and continued its work on general-purpose computers. According to Wikipedia, Nim itself continued to be used as a demonstration program on several other computers in the following years, including NUSE (1954), SMIL and SILLIAC (both 1956), Odra 1003 (1962), and Nimbi and Antinéa (both 1963). According to Wikipedia, the Computerspielemuseum Berlin has a Nimrod exhibit on display.

Was it the first "video game," and why it belongs in this category

According to Wikipedia, Nimrod is considered an early candidate, possibly the second, for the first video game in history — but whether it qualifies depends on the definition itself: it had no screen at all, and showed its state only through light bulbs. It came four years after a 1947 cathode-ray-tube amusement device, and one year after "Bertie the Brain," a purpose-built computer that played tic-tac-toe at the Canadian National Exhibition in 1950. According to Wikipedia, it was only in 1952 that OXO and Christopher Strachey's draughts program first displayed a visual result on an actual electronic screen — a step Nimrod and its contemporaries had not yet taken. Regardless of the "first" question, Nimrod is a very early example of a computer that plays against a person — decades before Deep Blue and AlphaGo. The key difference: Nimrod played according to a fixed rule programmed into it in advance, and learned nothing at all from experience or from previous games — exactly the kind of "artificial intelligence" this category is careful to distinguish from today's machine learning.