Computers
The computer is one of the most important inventions developed by man in the second half of the twentieth century. It was not so long after its invention that it became the backbone of many activities and significant fields in man's life. We could even say that we live in the computer age!
Pre-Computer Age
Ever since man started to perform mathematical operations, he began to think over an easy means to assist him to achieve what he wants to do quickly and easily.
First, he started by using his fingers in counting, and then pebbles. Later on, he invented a significant device called the abacus. An abacus is a tablet or frame with grooves or wires whose counters or beads can be moved for counting. Man continued attempting to develop a mechanical calculator. The French physicist and mathematician, Blaise Pascal, managed to invent the first generation of calculators in 1642. This calculator would automatically perform adding, subtracting, and multiplying operations. Later on, more sophisticated calculators were developed. The ‘Analytical Engine’ developed by the British mathematician, Charles Babbage, between 1835 and 1848 is considered the basis on which modern calculators are built. In 1886, Herman Hollerith created a system of recording and retrieving information on punched cards. This system was used in the official census of the United States of America in 1890. Then many inventions were developed later which paved the way for the emergence of the automatic numerical computer.
The First Computer
In 1944, Howard Aiken from the American Harvard University built the first program-controlled electromechanical computer.
It was 15 m long and 2.4 m high. Simple addition or deduction took 0.3 second while multiplication took 4 seconds, and division 12 seconds.
Two years later, John Mauchly and John Presper Eckert from the University of Pennsylvania, managed to build the first general purpose, fully electronic digital computer. In just one hour, their computer could perform the same operations that Howard Aiken's computer needed a whole week to perform.
After the development of transistors –small-size devices used for organizing the flow of electrical current – in 1947computer manufacturers started using them in assembling their computers. In 1960, the first computer provided with a transistor emerged in the markets. It was relatively smaller in size than the electromechanical computers and it was called a ‘mini-computer’.
In 1963, instead of transistors, the first integrated circuit computer first appeared. An integrated circuit is a tiny chip or slice made of silicon. The width of a chip or slice may not be more than 2 mm but it contained hundreds of transistors. Lines or buses are imprinted on these chips to make an electric circuit which allows the flow of electricity. These chips are then tightly coated with a plastic cover for protection. Small pins, connected to the chip itself protrude through the cover.
In 1971, an American company managed to manufacture microprocessors. A microprocessor is a tiny silicon chip containing thousands of electronic integrated circuits. The invention of the microprocessor made it easy for millions of people to have home computers because it is cheaper and smaller in size than the first generation of computers.
Computers with microprocessors are called micro-computers or personal computers.
What Is a Computer?
It is an electronic device that receives data or information, stores them, automatically retrieves them, converts them into more useful information, and tells the user all
about them. A computer could also perform all mathematical operations and solve mathematical questions and formulas very quickly and accurately.
Computer Components
A computer consists of hardware and software.
A program is a package of instructions given to the computer telling it how to accurately perform a required task. Programs are saved either on magnetic disks, floppy disks, or CDs. Users can purchase ready-made programs or customize them.
Computer Hardware
The several physical components that are used to build a computer are called hardware. Hardware includes:
Central Processing Unit
The Central Processing Unit (CPU) is a significant component of a computer. It consists of a complex set of electronic circuits that store and execute operations and commands. This unit is divided into three parts:
- Control unit
- Arithmetic/logic unit
- Main memory which receives data and stores it until needed. It could also store different programs.
The Central Processing Unit is the backbone of the computer as it is responsible for data processing, and setting all operations such as data input and output, control, and speed.
Input Devices
A computer has a set of devices that input or feed it with data and various programs. The most important of these devices are:
- The Keyboard
The keyboard is similar to that of a typewriter but it has some additional keys. A computer user could type the information fed into the computer including letters, numbers, or symbols through the keys on this keyboard. Once typed, data is displayed on the computer screen and it is simultaneously fed into the computer memory for storage. Through the keyboard, the user could also give the required commands to the computer for execution.
- The Mouse
It is an alternate device for the keyboard. It looks like a small box and it is used in giving commands to the computer. When the user moves the mouse over a flat surface, the on-screen mouse cursor moves accordingly to point to a command or an icon. Once clicked by the mouse, the command is executed. This device made it especially easy for beginners and non-specialists in using with the computer.
- The Scanner
It is a device similar to a small photocopier. It is used for digitizing optical copies of pictures and paper documents into the computer.
- The Light pen
The light pen allows the user to draw pictures on the screen and store them later in the computer memory. It is especially useful in framing designs.
- Joystick
It is used with various computer games.
Output devices
These are the devices that display the processed data to the user, the most important of which are:
- The Monitor
It is similar to a TV screen and it displays data, graphics, etc.
- Printer
It is a small printer that produces or prints data, texts, and images on paper.
- Plotter
It is used in producing large size maps and charts.
- Speakers
They produce sound.
Secondary storage
Because the computer’s main memory has a limited capacity, the computer needs a secondary storage media which has larger storage capacity.
There are two important types of secondary storage:
- Magnetic tapes which are not used in personal computers
- Disks which are divided into two types: magnetic and optical
- Magnetic disks
Magnetic disks include floppy disks. These disks are made of a flexible material and are put into a tight box. The user inserts the floppy disk into its slot in the computer to copy data from the disk to the computer or vice versa. The other type of magnetic disk is the hard disk. It consists of a number of magnetic platters that spindle on one axis. The hard disk is mounted inside the case of the CPU. The hard disk handles data much faster than floppy disks. For this reason, most frequently used software and data are stored on the hard disk which could be used without the need to change disks.
- CDs
Compact disks are considered the most recent development in secondary storage technology. Data is stored on them through extremely tiny digging made by laser beams.
The Main Idea by which the Computer Processes Information and Data
The main idea by which the computer processes data, depends on a fairly simple theory. It assumes that most processing relies on the basis of numeric signals. Hence, all input data, whether they are words, numbers, or symbols, will take the form of binary digits or the so-called binary system. It is a system that contains only two numbers: 0 and 1. The electronic circuit represents these two signals; meaning that it may be either ‘on ‘" i.e. ‘1’ or ‘off’ ‘0’. Numbers in this system could be represented as follows:
Number in the decimal system
0
1
2
3
4
5
6
7
8
9
10
Number in the binary system
0
1
10
11
100
101
110
111
1000
1001
1010
Computer networks:
Communication devices are used in connecting computers. For example, the modem is used for connecting a computer to a telephone line and hence this computer could be connected to one computer or more. In this case, the connected computers are called a ‘network’. Depending on their size, computer networks are divided into two types:
Local area network:
Its interconnected computers are separated by short distances such as in a building or even a room.
Wide area network
It interconnects millions of computers over large distances throughout the globe. A prime example is the World Wide Web. Through this network, you can send messages everywhere via e-mail. You can also obtain information on any topic by visiting the relevant web site. There are millions of sites available nowadays. For instance,
www.islamweb.net is a very significant and beneficial to Muslims generally and to children specifically.
The Use of the Computer
Computers are extremely important in our life. There is almost no field or activity without the computer having a role to play. It is an important factor in the fields of industry, commerce, agriculture, communications, education, medicine, diagnosing diseases, meteorology, space, and entertainment, and much more.
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