OVERVIEW OF THE COMPUTER SYSTEM
INTRODUCTION:
The term ‘computer’ is derived from the word ‘compute’ which means to calculate. A computer is an electronic machine, devised for performing calculations and controlling operations that can be expressed either in logical or numerical terms. In simple words, a computer is an electronic device that performs mathematical and non-mathematical operations with the help of instructions to process the data to achieve desired results. Although the application domain of a computer depends totally on human creativity and imagination, it covers a huge area of applications including arts, education, government, industries, medicine, music and even scientific research.
Computer is a programmable machine that can store, retrieve and process data. This means it can execute a programmed list of instructions and respond to new instructions that is given.
It can also be defined as an electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.
Today’s computers have at least one CPU that performs most calculations and includes a main memory, a control unit, and an arithmetic logic unit. A computer is a device that accepts information (in the form of digitalized data) and manipulate it for some result based on a program or sequence of instructions on how the data is to be processed.
CHARACTERISTICS OF COMPUTERS
There are certain qualities possessed by the computer that tend to make it advantageous over other means of data processing. Some of these qualities are.
Accuracy: Computers do not make mistakes in so far as they are accurately programmed and are not faulty in terms of components. Because computers can operate error-free, they can be trusted to produce accurate results, which is very vital to the users. Besides being efficient, the computers are also very accurate. The level of accuracy depends on the instructions and the type of machines being used. Since we know that computer is capable of doing only what it is instructed to do, faulty instructions for processing the data automatically leads to faulty results due to faulty instructions or incorrect input data are known as GIGO, that is, “Garbage In Garbage Out”.
Diligence: Computer, being a machine, does not suffer from the human traits of tiredness and lack of concentration. If four million calculations have to be performed, then the computer will perform the last four-millionth calculation with the same accuracy and speed as the first calculation.
High Speed: Computers are electronic devices and as such, can operate at the speed of electricity. This makes the computer so fast in operation that in a matter of seconds, the computer can accomplish what will take human beings days to do. The computers process data at an extremely fast rate, i.e. at millions or billions of instructions per second. In a few seconds, a computer can perform a huge task that a normal human being may take days or even years to complete. The speed of a computer is measured in megahertz (MHz), that is, one million instructions per second.
Mass Storage Capacity: Computers can store very large amounts of data for long periods of time. Computers can store large amounts of data and it can recall the required information almost instantaneously. The memory of the computer is relatively small and it can hold only a certain amount of information. Therefore, the data are stored on storage devices such as magnetic tape or disks. The data from these devices can be accessed and brought into the main memory of the computer, as and when required for processing.
Reliability: Generally, reliability is the measurement of the performance of a computer, which is measured against some predetermined standard for operation without any failure. The major reason behind reliability of the computers is that, at hardware level, it does not require any intervention between its processing operations. Moreover, computers have built-in diagnostic capabilities, which help in continuous monitoring of the system.
Resource Sharing: In the initial stages of development, computer used to be an isolated machine. With the tremendous growth in computer technologies, today’s computers have the capability to connect with each other. This has made the sharing of costly resources like printers possible. Apart from device sharing, data and information can also be shared among groups if computers, thus creating a large information and knowledge base.
Security: Because data and information in computer systems are stored in machine-readable forms, they are protected to some extent from people who have no access to the computer by use of passwords or some other form of identification. Thus, we can say that the computer provides a measure of security for data and information stored in it.
Versatility: Computers are quite versatile in nature. They can perform multiple tasks simultaneously with equal ease. They can be used in many fields. Some areas in which the computer can be used include accounting, airline seat reservation, designing, entertainment, exam marking, learning, manufacturing, military, payroll, etc. For example, at one moment it can be used to play music and in between one can print a document as well. All this work is possible by changing the program (sequence of instructions for the computers).
ADVANTAGES OF COMPUTER
There are many advantages of using computers in larger resource centers, or smaller resource centers that have a large number of periodicals, serve many users based at a distance, or provide a wide variety of services. The main advantages of computers are:
Increased access to the information in the resource center
Increased efficiency
More information sources
More opportunities for cooperation and networking
More services
INCREASED ACCESS TO THE INFORMATION IN THE RESOURCE CENTER: The main way to search for materials using a catalogue card system is by author, title, and a limited number of keywords. To add more keywords or other details would require more cards. This would require more work, and the catalogue would become larger and more difficult to keep up-to-date. A computer database enables materials to be searched using more keywords, or using other details such as series, titles, publisher, year published or individual words from a title if the full title is not known, all without extra work.
INCREASED EFFICIENCY: Information stored on a computer database can be used for different purposes. For example, details of materials entered onto a database when ordering them can be used for a catalogue, simply by adding classification numbers and keywords. The same records can be used to produce current awareness bulletins or resource list.
MORE INFORMATION SOURCES: A computer with a CD-ROM drive can provide access to materials stored on a CD-ROM, including databases (containing descriptions of materials) and full-text (complete) materials. A computer linked to a modem can provide access to information available via e-mail and other internet services, such as electronic newsletters and websites.
MORE OPPORTUNITIES FOR COOPERATION AND NETWORKING: A computer linked to a modem makes it easier to communicate with other resource centers, via email. Sharing information among different resource centers can improve user’s access to information and cut down duplication effort.
MORE SERVICES: A computer can be held to ‘repackage’ information held on a database, in the form of directories, resource lists or current awareness bulletins. Information held on the computer or available via the Internet can be adapted to produce locally relevant materials.
DISADVANTAGES OF COMPUTER
IT CANNOT GENERATE INFORMATION ON ITS OWN: Your computer depends on you. It will not run unless you operate it, in the same way, it cannot give you information you need if you do not feed it with the necessary data.
THE COMPUTER CANNOT CORRECT WRONG INSTRUCTION: If you give the computer wrong instruction, it will not be able to do anything to correct it. It will only stop functioning. Then, the computer will depend on you to correct its mistake.
THE COMPUTER CAN ONLY DO WHAT YOU TELL IT DO: Do not expect the computer to give you something which you never tell it to do. It will only give you what you ask it.
THE COMPUTER WILL GIVE YOU WRONG INFORMATION IF YOU FEED IT WITH WRONG DATA: The computer cannot distinguish between correct data and wrong data. Thus, if you feed your computer with wrong data, it will result in the computer giving you wrong information.
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