4. KEY COMPONENTS

1.     The store: A memory wheel consisting of set of counter wheels

2.     The mill: An arithmetic unit capable of performing the four basic arithmetic

3.     Operations. It operated on pairs of mechanical registers and produced a result stored in another register, all of which were located in the store.

4.     Operation cards: These cards selected one of the four arithmetic operations by activating the mill to perform the selected function.

5.     Variable cards: These cards selected the memory locations to be used by the mill for a particular operation ( a source of operand and the destination of the result ).

6.     Output: was to print or a card punch device.

  • Herman Hollerith’s Tabulating Machine

Herman Hollerith was a statistician, in 1880; he developed the tabulating machine commissioned by the U.S. Census Bureau.

Mark I: Developed by Howard Aiken at Harvard University in 1944, Mark I, was the first electromechanical computer. Instructions were provided by means of punched paper tape, which combined the functions of Babbage‘s operation cards and variable cards. Each instruction had the format: A1 A2 OP , where A1 and A2 are registers storing the operands and OP is the operation to be performed( e.g. +,-,x,%). Mark I, was able to do a single addition in 6 seconds and division in 12 seconds.