PFE top 1

• A common marketing tool to attract more consumers

  Internet
• computers truly came into their own as great inventions in the last two decades of the 20th century
• Computer’s history stretches back more than 2500 years to the abacus
• A simple calculator made from beads and wires, which is still used in other parts of the world today

  Abacus
• abacus is invented in the middle east circa 500 bc, and it remained as the fastest form of calculator until the middle of the 17th century
• In 1642, aged only 18, french scientist and philosopher blaise pascal (1623-1666) invented the first practical mechanical calculator, the pascaline, to help his tax collector father do his sums
• The machine has interlocking cogs that could add and subtract decimal numbers

  Pascaline
• in 1671, german mathematician and philosopher gottfried wilhelm leibniz (1646-1716) came up with a similar but more advanced machine. instead of using cogs, it had a stepped drum, an innovation that survived in mechanical calculators for 300 years


  leibniz machine
• This calculator could do so much than pascal’s: as well as adding and subtracting, it could multiply, divide, and work out square roots. Another pioneering feature was the first memory store or register


  Leibniz machine
• He was the man who invented binary code

  Leibniz
• it is a way of representing any decimal number using only two digits , zero and one


  binary code
• in 1854, englishman george boole (1815-1864) used the idea to invent a new branch of mathematics called boolean algebra
• In modern computers, binary code and boolean algebra allow computers to make simple decisions be comparing long strings of zeros and ones.
• a computer is a machine that can operate automatically, without any human help, by following a series of stored instructions called a program
• it is an evolved calculator

  Computer
• the first person to attempt making a computer was the english mathematician named charles babbage (1791-1871)
• He designed the Difference engine

  charles babbage
• the difference Engine was a fully automated calculating machine. It wa designed to carry out intensive mathematical computations. It operated by leveraging the power of steam.
• The difference engine was funded by the government until 1842
• the analytical engine is widely regarded as the predecessor of the modern computer. Charles babbage started working on this in 1843. He also created 100 drawings for this.
• Babbage was helped by augusta ada lovelace byron, daughter of the poet lord byron in develoing analytical engine. She documented the design of the engine and her notes were valuable in understanding the design.
• Augusta helped refine babbage’s ideas in making his machine programmable that’s why she is still, sometimes, referred to as the world’s first computer programmer
• even though little of babbage‘s work survived after his death, his notebooks were rediscovered in the 1930s
• Towards te end of the 19th century, other inventors were more successful in their effort to construct engines of calculation
• Americal statistician herman hollerith built one of the world’s first practical calculating machines called a tabulator
• In the 1880s, the population of US had grown so much through immigration that a full scale analysis of the data by hand takes 7 and a half years
• hollerith’s tabulator was an amazing success, it tallied the entire census in only 6 weeks and completed full analysis in just 2 and a half years
• Tabulating machine company was set up in 1896 and by 1924 it acquired its present name, international business machines
• the world’s most powerful calculators were being developed by US government scientist vannevar bush
• bush built a machine called differential analyzer, which used gears, belts, levers, and shafts to repreesent numbers and carry out calculations in a very physical way
• Bush’s ultimate calculator was the rockefeller differential analyzer, assemble in 1935 from 320km (200 miles) of wire and 150 electric motors. machines like this were known as analog calculators.
• The teacher of claude shannon, a brilliant mathematician who figured out how electrical circuits Could be linked together to process binary code with boolean algebra
• in 1945, an idea for a memory storing and sharing devicee called memex was proposed by Vannevar Bush. it would later inspire tim berners-lee to create the world wide web
• Alan turing was a brillian cambridge matheematician whose major contribution were to the theory of how computers processed information
• a simple information processor that works through a series of instructions, reading data, writing results, and then moving on to the next instruction

  turing machine
• turing is the father of modern computing
• it is a simple way to find out whether a computer can be considered intelligent by seeing whether it can sustain a plausible conversation with a real human being

  turing test
• In 1938, german engineer konrad zuse constructed. Z1, the world’ss first programmable binary computer, in his parents’ living room
• american physicist john atanasoff and his assistant electrical engineer clifford berry built a more elaborate binary machine that they named atanasoff berry computer
• These were the first machins that used electrrical switches to store numbers

  atanasoff berry computer