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Computers

Charles Babbage and Lady Ada Lovelace in the 1840s designed an analytical engine, which could not actually be constructed due to lack of techniques for manufacturing precise components.

Recall Boolean algebra in 1854. (Introduction to logic circuits in Shirish's seminar)

Claude Shannon (MIT master's thesis 1938) showed that electrical relays and switches doing Boolean algebra could be used to simulate Turing's universal computing device and thus perform arithmetic operations.

During WW II Turing used electronic valves to build special-purpose computing machines to break German codes.

In the United States, the demands of war led to the development of ENIAC (Electronic Numerical Integrator and Calculator, the first electronic computer, which had been designed for computing weapons trajectories (though, switched on in 1946, it was a little too late to help the war effort). ENIAC's design was based on Turing's and Shannon's work and the vN architecture.

American mathematician John von Neumann contributed many important conceptual breakthroughs to the organization of the computer hardware. The modern computer architecture is often referred to as the von Neumann architecture.

The von Neumann (vN) architecture: Distinction between memory and CPU. vN realised that a program, i.e. a set of instructions could be stored in memory in the same way as data could. Computer operations were carried out in cycles in the CPU. In each cycle both data and instructions are read from memory into the CPU which carries out the instructions and return the results to memory.

A vN computer with infinite memory, if properly programmed, could be a Universal Turing Machine.

Recall that von Neumann was also (in 1945) among the first to speculate on the connection between the new technology and the human brain. He died of cancer before seeing the publication of his book The Computer and the Brain (von Neumann, 1958).


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Next: Simulating human thinking - Up: AI Lecture 1 Previous: Problems with the computational   Contents