The Abacus

• At least 5,000 years old
• Memory aid for making mental calculations
• Not a true mechanical calculating machine
• Eventually replaced by pencil and paper

• French mathematician
• Built the first mechanical adding machine in 1642 (the Pascalene)

• Invented Jacquard loom in 1801
• Fabric patterns controlled by punched cards
• Could produce fabrics faster and more accurately than any human
• Knowledge stored in cards could be spread easily
• Machine could be tended by unskilled factory workers
• Caused riots in 1811 by skilled craftsmen fearing for their jobs (the Luddites)

• English mathematician and inventor
• Frustrated by errors in mathematical and navigation tables
• Produced prototype of Difference Engine in 1822
• Used clockwork technology (wheels, cogs, and shafts)
• Designed to solve polynomial equations (e.g., 3.56x⁷ - 7.6x³ + 2.39x - 8.94 = 0)
• Never completed
• Working version built in 1991 at the Science Museum of London using only technology available in Babbage's time

• Difference Engine inspired Babbage to design the Analytical Engine in 1833
• Steam-powered design
• General-purpose programmable machine
• Designed to store 1000 numbers of 50 decimal digits each
• Composed of several devices:
  • one to receive instructions coded on punched cards (like Jacquard loom)
  • one to perform the coded instructions
  • one to store results of intermediate calculations
  • one to print out information on paper
• Virtually identical in design to a modern computer
• Never built

• Daughter of Lord Byron
• Babbage's patron, assistant, and chronicler
• Wrote sets of instructions for the Analytical Engine
• World's first computer programmer
• U.S. Department of Defense named its programming language Ada after her
• "The Analytical Engine weaves algebraic patterns just as the Jacquard loom weaves flowers and leaves"