1. DPW Network Security 101 Session 1

2. DPW Early Mechanical Computers AbacusPascaline machine Napier’s Bones Stepped Reckoner Arithmometer Punch cards Babbage’s Difference Engine B.C. 1617 1642 1673 1820 1801 1832

3. DPW An Abacus (BC) A mechanical device used for counting. Addition, subtraction, multiplication and division can be performed on a standard abacus. Using the abacus is still taught in Asian schools and still used by shopkeepers in Asia and “Chinatowns” in the USA.

4. DPW Napier’s Bones (1617) of logarithms and calculate based on relative position of the scales and when bound together created the first slide rule.  John Napier’s bones work on the principal