1. Mathematical Tables  Scientists  Navigators  Engineers  Surveyors  Actuaries  Actuaries A random selection of 40 volumes of numerical tables contained 3,700 acknowledged errata and ?!?!?!? unacknowledged ones Dionysius Lardner (1834)

2. 1800’s Further development of mechanical calculating machines

3. Thomas de Colmar  stepped drum gears  reverse the operating function in the result registers (up to 16 digits), allowing reliable, stable calculation over extended periods of time without gear re- alignment 1785-1870

4. arithmometer 1820 -1830 1500 models sold 1820 -1830 1500 models sold  banks  insurance companies  similar businesses

5. Thomas promotes arithmometer Piano ArithmometerGift for Tsar Nicolas I

6. Maurel & Jayet 1840’s  Took basic design of Thomas and greatly improved it  Results as high as 8 digits  Transmission too delicate The Arithmaurel

7. Odhmer Baldwin Swedish engineerAmerican engineer fluted drums replaced by a "variable-toothed gear" design: a disk with radial pegs that can be made to protrude or retract from it. 1845-19031838 to 1925 Pin-wheel mechanical calculators

8. The typewriter Introduction of the keyboard

9. The first adding machine with keyboard It was feasible because of a carry mechanism fast enough to act while the keys return from being pressed Dorr E. Felt (1862-1930) Comptometer Chicago 1884 Worldwide success

10. The disadvantages of these machines  Operation required direct manipulation by the operator  Multiplication performed as successive additions  Keyboard improved speed but…  Well trained operator still necessary

11. Charles Babbage 1791 - 1871  English mathematician Born in Teignmoth, Devonshire, UK  analytical philosopher  proto-computer scientist

12. The Difference Engine N o 1 Designed to produce mathematical tables Construction funded by British government and Babbage himself Never completed Babbage lost interest in this device when he realized that its design was flawed He started working on Difference Engine No 2

13. The Difference Engine N o 2 design completed 1830 built 1991

14. The Analytical Engine Babbage formulated ideas for it between 1834-1837

15. The Analytical Engine Store - 1000 50-digits numbers Mill – (CPU) added, subtracted, multiplied or divided, and returned a result to the store Punched cards – several readers for programs and data Printer for output making hardcopy data available to the user 

16. Why did Babbage not invent the computer?  Machine tools not adequate in his day  Mathematics and logic not sufficiently developed  Mechanical memory store just too slow and too limited to hold a useful program

17. Augusta Ada Byron Countess of Lovelace Augusta Ada Byron Countess of Lovelace  Daughter of Lord Byron famous romantic poet  Her mother did not want her to grow up to be a poet….  Competent mathematician  Member of London’s high society

18. Ada 1815 - 1852  Met Babbage when she was 17  Public relations for Babbage  Translated an article by Luigi Menebrea on the A.E. and added extensive notes  Some give her credit for writing the first computer program

19.  New Yorker of German origin  Trained as a mining engineer  Ph.D at MIT  Developed a mechanism for reading holes in the cards using spring-mounted needles  Needles passed through the holes to make electrical connections to trigger a counter to record one more of each value Herman Hollerith Electronic tabulation of statistical data 1860-1929

20. 1890 census completed in record time

21. Built tabulators on a contract for the US government Built tabulators on a contract for the US government Many other governments wanted tabulators too Many other governments wanted tabulators too Started Tabulating Machine Company in 1986 Started Tabulating Machine Company in 1986 Merged with 2 others in 1911 Merged with 2 others in 1911 Changed name to IBM in 1924 Changed name to IBM in 1924