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WEEK: 4
TOPIC: COMPUTING DEVICES
CONTENT:
Features, components and uses of: (i) Abacus (ii) Slide rule (iii) Napier’s bone (iv) Pascal’s calculator (v) Leibnitz multiplier (vi) Jacquard’s Loom (vii) Charles Babbage (viii) Analytical Engine (xi) Hollerith Census Machine (x) Burroughs’s Machine.
SUB-TOPIC 1: FEATURES, COMPONENTS AND USES OF COMPUTING DEVICES
ABACUS: Abacus is an instrument used in performing arithmetic calculations. It is probably the first calculating device. The Chinese invented it, and because of its success it spread from China to other countries. The abacus is also called a counting frame, it consist of a tablet or frame bearing parallel wires or grooves on which counters or beads are moved. A modern abacus consists of wooden frame with beads on parallel wires, and a crossbar oriented perpendicular to the wires that divides the beads into two groups. Each column or wire represents one place in the decimal system. The Abacus was used for addition and subtraction. It could not carry out complex mathematics operation.
SLIDE RULE: Slide rule is a mechanical analog computer.It is also known as slipstick. It is used primarily for multiplication and divisions, and also for functions such as roots, logarithms, and trigonometry. It is not normally used for addition and subtraction. Slide rule come in a diverse range of style and generally appear in a linear or circular form with standardised set of markings(scales) essential to perform mechanical operations.
The slide rule was developed by William Oughtred, an English mathematician. The slide rule looks much like a heavily caliberated ruler with a movable mid section.
NAPIER’S BONE: Napier’s bones is an abacus created by John Napier of Merchiston for calculation of products and quotients of numbers, in 1600. John Napier was a Scottish mathematician who invented logarithms and the decimal point. The device consists of a set of graduated rods based on the principle of logarithms. It was then used as a multiplication aid.
To use Napier’s bones, the rods are moved up and down in a sliding manner against each other, matching the graduated rods. The device was a fore-runner of the slide rule which emerged in the middle of 17th century. Formerly used to perform multiplication and division but now taken over by modern electronic calculator.
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