Electronic Digital Computers With An Introduction To The Analog Computer And The Digital Differential Analyzer
Computers either measure "how much" or count "how many". The former is known as an analog computer while the latter is called a digital computer. Of all the creatures on earth, only man has the ability to count. Ancient man first used his fingers to relate the idea of "how many" to some physical object that he could see and use to express to someone else. Even today primitive societies use this method. A Sibiller tribesman of New Guinea can only count up to 27. Using his right index finger, he points to his left-hand finger for the numbers (1-5), he then points respectively to his left wrist, forearm, elbow, bicep, collarbone, shoulder, ear and eye for (6-13). The nose is (14). Now using his left index finger, he travels down his right side for (15-27J.1 As man progressed, he introduced more complex computers than his fingers. Thousands of years ago some Egyptian merchants made a computer using sand and pebbles, using a number system based on ten fingers (or ten pebbles).