Brief History
- 1920's: Engineers configured telephone switches to do simple calculations like adding two
numbers.
- 1940's: First computers; occupied entire rooms.
- 1960's: Engineers could put multiple switches on a single chip. U.S. moon rocket program
brought dramatically improved chips and decreased prices.
- 1970's: Earlier room-sized computers could fit on one coin-sized computer chip.
- Moore's Law: The trend of switch sizes halving about every two years.
Charles Babbage (1791 - 1871)
Babbage invented the first automatic mechanical computer, the Difference Engine,
which was used
to calculate polynomial functions. The Analytical
Engine was the
Difference Engine's successor,
intended as a programmable computing engine. To
support general purpose computing the following components were added:
Arithmetic logic unit (ALU): Used to perform arithmetic. Called a "mill".
Conditional logic: Used to perform conditional
branching and loops.
Memory: The machine's memory could hold over 1,000 numbers containing 40
decimal digits.
Punched card reader: Used to input programs and data via punched cards.
Ada Lovelace (1815 - 1852) = first computer programmer
- The Jacquard Loom and the Analytical Engine both used punched cards to input specific
patterns or programs.
- The Analytical Engine included an ALU to perform arithmetic operations
The algorithm to compute the Bernoulli numbers and said to be the first computer program
was titled Note G