Introduction to computers what is a computer?
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- MICRO COMPUTERS.
- MAINFRAME COMPUTERS
- EXAMPLES: IBM 4341, IBM 4381, ICL 2900, and Control Data Cyber 176 etc .
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INTRODUCTION TO COMPUTERS
The name “computer” is derived from the Latin word computare, meaning “to compute” which means to calculate .So a computer is a machine which performs different kinds of tasks, such as communication, processes the data, store information, data and mathematical calculation on different media. OR A computer is an electronic device, which is used to input, output, process, store and analyse data to get specific result. OR A computer is an electronic machine that can transmit, store and manipulate data or information, which can be numeric or character type. OR A computer is an electronic device or machine that stores, retrieves and process information. A computer solves computing problems involving words or numbers or both. It helps us to solve our wide and varied problems accurately and quickly. The problems may relate to fields such as industry, commerce, medical, engineering and education. The computer can perform many functions with great speed. It can perform the task in a few seconds that human being can do in a year. The computer is also very accurate in calculations. In these days, computer is a very important thing in daily life. But some fields are totally based on computer and without computer they cannot do any thing such as:
The major characteristics of computers, which have made them so powerful and useful, are:
Types of Computers (According to their working) There are three basic kinds of computer classified according to their working.
This computer can accepts an analog input and provides an analog output of information. In other words, it is a computer, which deals with variables that are measured along a continuous scale and are recorded to some predetermined degree of accuracy. Analog computers are used to measure continuous values. An example is thermometer because it measures the length of a mercury column, which varies continuously. Another example is analog clock which measures time by means of the distance traveled by hand of the clock around the dial. Now a day, analog computers are mainly used for engineering and scientific works. They are used in paper making and in chemical industry. Analog computers do not require any storage capability because they measure and compare quantities in a single operation. Output from an analog computer is generally in the form of reading on a series of dial (speedometer of a car) or a graph on a strip chart. They are very fast in their processing but their result is not very accurate. Analog computers are faster than digital computer. Analog computers are also called special purpose computer because they are specially design to solve a specific problem. Examples: Distance, velocity, acceleration, temperature, pressure, voltage, current, a thermometer and a speedometer.
Digital means discrete. With signals, every thing is described in two states whether ON or OFF. A digital computer is designed to process data in numerical form .A digital computer is a computer, which measures in terms of digital quantities .A digital computer is based on the rule of counting .It perform directly the mathematical operation of addition, subtraction, multiplication and division. In fact, digital computer uses digital signals, which can distinguish between just two values 0 and 1. Digital computers used in scientific and business oriented jobs because digital computers are very useful in solving complicated arithmetical expressions/equations. The result of digital computers is more accurate, precise and repeatable than the result of analog ones. Analog computers lack memory whereas digital computers store information. The most common examples of digital computers are calculators and digital watches. Digital watches are good examples of digital computer, because the time, which is displayed, does not vary continuously but change from one discrete value to another. Types of Digital computer are Mainframe, Mini, Micro, General purpose and Special purpose Computers.
Besides Digital and Analog computers, there is another kind of the computer, called the Hybrid computer. Hybrid means that a thing which is made by two different things. So a Hybrid computer contains both digital and analog features. The Hybrid computer is the combination of the Digital and Analog computer, or in other words, a Hybrid computer has the characteristics of both Analog and Digital computers, which means that it is a computer which can measure both in terms of physical as well as digital quantities. They have the speed of Analog and accuracy of Digital computers. These computers are used in working out special types of problems in science and various areas of engineering such as space, vehicle simulations and training of astronauts. They are used mainly in specialized applications where both kinds of information need to be processed. These computers are designed to perform special task in which different measurements are converted into digits and are processed by the computer. Hybrid computers combine the high speed of Analog machine with the storage and decision-making ability of Digital computer. The flight simulator used by commercial airline for training pilots is an example complicated Hybrid computers. Hybrid computers make use of both analog and digital components and techniques and are mostly used for automatic operations of complicated physical processes and machines. But they are mostly hidden as in medical machine say ultrasound or C.T scan. Hybrid computers are mostly used in Air Defence. There are no types of Analog and Hybrid computers.
Digital computers are further divided into different categories according to their physical size, cost, speed, size of main memory, processing power, word size and other capabilities possessed by a computer. We can generally classify them into four categories:
Super computer were developed in 1980. Super computers, just like any other typical computer. The only difference between an ordinary computer and super computer is that super computers are largest, fastest and most expensive computers. They are used to handle complicated problems. These have extraordinary amounts of computing power required by large organization, scientific laboratories, aerospace centers, large industrial units research laboratories, etc. These computers are used in weather forecasting, aircraft design and nuclear researches. They are also used in a time-sharing mode in which thousands of users can be attached to the computer system at the same time. These machines are very difficult to design, require a lot of research and development and are very expensive to manufacture. Examples are CRAY-1 and CRAY-2 computers and Control Data Cyber 205 Super computers.
Mainframe computers are large-scale computers, very expensive machines and very powerful. Computer systems of this size require very large rooms and a special physical environment (for example Air Conditioning). Large systems can accommodate a large number and variety of supporting equipment. Mainframe computers are fast and sophisticated with very large memory. These are used in large organizations such as banks, government, universities and large corporations where, these support multiple users.EXAMPLES: IBM 4341, IBM 4381, ICL 2900, and Control Data Cyber 176 etc.Mainframe computers have the following characteristics:
Digital Equipment Corporation introduced Mini computers in the mid-1960s. Mini computers are increasingly powerful and do almost anything that large computers do, but more slowly and at much lower cost. This makes it ideal for small companies where capacity and speed of operations is not highly critical. These low cost computers use integrated circuits. Mini computers can also store relatively large amount of data. It can perform different tasks and support several users at a time but the power of processing is not as great of the mainframe computers. These computers are also used for networking. The numbers of users of each mini computer depends on the amount of memory in computer. More memory means that more users can access the system at one time. Examples: prime 9755, IBM system 36 etc.
Microcomputer is sometimes called a single-chip processor. It is also called personal computer (PC). Microcomputer is a digital computer system that uses a microprocessor (the CPU on a chip), a programmable ROM and a RAM. These are very fast and low cost. It is ideal for small businesses, engineering designs and for home use. These computers are used now a days commonly and these computers revolutionized the computers industry because of their size and low cost. They are also used by millions of person all over the world for entertainment and personal application. Most microcomputers use integrated circuits (ICs). It is very fast in human terms, it is much slower than the other two kinds. Microcomputers can be of the following types:
Examples: IBM, apple and IBM: 286, 386, 486, 586, Pentium II, and now Pentium IV as the latest.
These computers are designed to handle a variety of different jobs or problems and to meet different needs e.g. with a personal computer, a user can perform typing, can play games, can make graphs or can do arithmetic. General-purpose machines are strong in versatility but are normally weak in speed and efficiency as compared to dedicated computers.
It supports highly specialized data processing activity. Special purpose computers are also known as Dedicated Computers, because these are designed to perform a particular job. In other words, we can say that they are designed to handle specific problems e.g. they are used in computer games, control of traffic lights, navigational system of an atomic submarine, collecting highway tolls, airline reservations, satellite tracking, air traffic control and industrial process control. Many such systems have a set of instructions permanently programmed into them that are designed to perform only one major function. As these computers have to perform only one task, therefore, they are fast in processing. Directory: resources resources -> General text for tender (recommendations) for Pilkington Profilit™ Contents Page resources -> North Carolina Inclusion Initiative Mapping Where Children with ieps are Being Served Purpose resources -> Practice learning resources -> The Rise of Video Games Section “Word” Matt Spencer resources -> Request for proposal contract form for the transit industry resources -> Request for Proposal [insert date] resources -> The University of York 13th 16th April 2004 resources -> Biological and Biomedical Sciences Program Community Education Initiative resources -> Region III standing regional response team (rrt) meeting williamsburg, Virginia Thursday, January 12, 2012 resources -> Efca eastern District and TouchGlobal, the crisis response ministry of efca Download 28.89 Kb. Share with your friends:
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