From the history of computer
The educated man of 200 years ago did not need to know anything about science. The educated man of 25 — 30 years ago did not need to know anything about computers. But the educated man of today needs to have some significant knowledge of science and a little significant knowledge about computers.
The computer is no doubt the most amazing achievement of mankind. It is a date storage system created by man. A human tells the machine what to do, when to do it and how it should be done.
The word computer comes from a Latin word which means to count.
Nearly one hundred and fifty years ago there were no such things as computers. Knotted ropes, marks in clay, the abacus are all methods of keeping track of numbers.
In 1833 an English inventor and mathematician Charles Babbage, professor of Cambridge University designed the first computer. The mathematical programme for his machine had been composed by Lord Byron's daughter.
The first programmer computer which operated successfully was built in 1939 by H. H. Aiken, professor of Harvard University.
In our country the first electronic digital computer MACM was constructed by the Ukrainian Academician S. O. Lebedev in 1950.
Such computers as BESM, Minsk, Ural, Razdan-3, M-20, M-220, Nairi-3, Strela, Dnieper were created in our country.
Nowadays computers greatly increase man's thinking capabilities of planning, analyzing, computing and controlling. Hundreds of computers are already in daily use. They penetrate almost into all spheres of our modern society, from nuclear energy production and missile design to the processing of bank checks, weather forecasting, manufacturing, research and medical diagnoses.
There are three kinds of computers: digital, analogue and hybrid. An analogue computer computes by using physical analogue of numerical measurements. A digital computer computes by using numbers or digits. A hybrid computer is a machine which combines some of the properties of digital and analogue computers.
Invention of electronic computers is one of the greatest achievements of mankind. The significance of it can be compared with the invention of the steam-engine and the utilization of atomic energy.
Three basic steps of the computer
INPUT
A program provides the basic instructions the computer must follow in order to do a specific job. Like the basic rules of a game, the program is only the beginning, however. In order to do a job, the computer and the program must also have input. Input is the data and additional instructions you give to a computer to enable it to do a specific job. The input may be in the form of numbers, letters, words, or pictures.
The computer may receive input through a keyboard, which looks very much like the keyboard on an ordinary typewriter. It may also receive input from a disk or cassette. Until a computer receives input, it can do nothing.
PROCESSING
What does a Computer do with the information it receives? Like the human brain, it sorts information, puts it into usable form, and does calculations. This step is called processing.
OUTPUT
Finally, the computer does something with the information it processes. It usually displays the results, often on a screen or on paper. The product of computer processing is called output. Output is the information the computer produces as a result of its work.
You are likely to see this three-step process — input, processing, output — in many day-to-day activities, such as when you use a pocket calculator. In a calculator the input consists of numbers that you press on its keypad — let's say the numbers 3 and 7. The processing occurs after you tell the calculator what you want it to do for example, multiply. The output — 21 — appears on a little screen at the top of the calculator.
The calculator can process the same information in different ways. You might have asked it to add the two numbers, in which case "10" would have appeared on the screen.