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Maths and the History of ICT. Charles Babbage. 1791-1871 English Mathematician and Philosopher Originated the concept of a programmable computer. Computers. In Babbage’s day a ‘computer’ was a person who was good at arithmetic and was employed to work out the results of calculations.
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Charles Babbage • 1791-1871 • English • Mathematician and Philosopher • Originated the concept of a programmable computer
Computers In Babbage’s day a ‘computer’ was a person who was good at arithmetic and was employed to work out the results of calculations. There were many errors, so Babbage set out to build a machine that could do the calculations. It used the concept of ‘finite differences’ so avoided the need for multiplication and division.
Babbage’s Difference Engine Part of Babbage’s Difference Engine
Babbage’s Difference Engine A Difference Engine built from Babbage’s design.It weighs 13600 kg.
Babbage’s Brain Babbage died at the age of 79. His brain was cut in two. Half of it is preserved at the Hunterian Museum in the Royal College of Surgeons in London. The other half is on display in the Science Museum, London.
Ada Lovelace • 1815-1852 • English • Writer • Daughter of poet Lord Byron • The first computer programmer
Ada Lovelace Although she never saw Babbage’s Difference Engine completed, she wrote the first computer program for it for finding Bernoulli Numbers. In 1980 a computer language used by the US Department of Defence was named after her: ‘Ada’. March 24 is commemorated by some as Ada Lovelace Day. This is a day to celebrate the achievements of woman in technology and science.
George Boole • 1815-1864 • English • Contributed to: • Logic • Maths philosophy • Married daughter of George Everest • Developed Boolean Logic
Boolean Logic This is a special algebra which uses the values 1 and 0 only. These values 1 and 0 are sometimes called ‘true’ and ‘false’. There are a number of operations, the primary ones are:and & or || not ¬ xor ⊕ (called exclusive-or) This logic is at the heart of your computer and helps it make decisions and do arithmetic.
Boolean Logic The operations can be shown in ‘truth tables’. This is the truth table for the operation and: The result is True when both pand q are True. If 1s and 0s are used it is the same as multiplication
Boolean Logic This is the truth table for the operation or: The result is True when either por q are True.
Boolean Logic This is the truth table for the operation not: The result is the opposite of p.
Boolean Logic This is the truth table for the operation xor: The result is True when either por q are True but not when they are both True.
Boolean Logic This combination is called NAND (i.e. not and) Some combinations of operations can be show to be equivalent to other combinations.
Alan Turing • 1912-1954 • English • Contributed to: • Logic • Cryptanalysis • Computing • Broke war codes created by the German ‘Enigma’ machine • Significant in creation of the modern computer