Introduction to Copmputer
Introduction to Computer
This is knowledge kingdom and teaches you what is computer and other topics that are given below
You will learn about:
Hardware Software
1. Input Devices 1. Systemsoftware
2. Output Devices 2. Utility Software
3. Application Software
A computer is an electronic machine. it accepts the input and processes it according to sequence of instructions to get the desires output. For this process, three essential components are required, namely, input devices, central processing unit (CPU) and output devices. Input and output devices provide the means of communication between the computer and its user. These devices work together with the help of software and hardware, and are called computer peripherals.
HARDWARE
The physical parts or components of a computer system that you can see, feel and touch are called hardware. Hardware of computer can be categorized as input and output devices, storage unit and the central processing unit (CPU). We have already learnt about input and output devices such as keyboard, mouse, monitor, joystick, light pen, scanner, microphone, speakers, printer etc. Now we will learn about some input and output devices that are mainly used for commercial purposes.
Input Devices
An input device is an electro-mechanical device which is used to provide data and instructions to the central processing. Some input devices are used in banks, supermarkets, etc. to read and capture a big amount of data quickly. Some of the input devices used for commercial purpose are Barcode Reader, Optical Character Reader (OCR), Optical Mark Reader (OMR), Magnetic Ink Character Reader (MICR) and Trackball.
Barcode Reader
Barcodes are the printed horizontal stripes of vertical bars in a machine-readable format which are used for identifying specific items. In a barcode, data is represented by the width of bars and distance between them. It gives us the details of manufacturer and the product. A Barcode Reader scans a little label that has a barcode on it. The information is then saved on the computer. It helps a computer in keeping track of the items sold.
Optical Mark Reader (OMR)
An Optical Mark Reader is used to detect pen/pencil marks of pre-specified shape on a sheet of paper. It is used to check answer sheets with objective type questions where students are asked to make specific marks to indicate their answer. When a beam of light is passed through the OMR sheet, the marked areas reflect less light than the unmarked areas. Hence, the Optical Mark Reader recognizes which options are marked. This process is called optical mark recognition.
Optical Character Reader (OCR)
An Optical Character Reader is used to enter text into a computer. It first produces a digital image of the text. Then, this digital image is converted into characters using character recognition software. These characters can be stored and processed by the computer. This process is called optical character recognition.
Magnetic Ink Character Reader (MICR)
The Magnetic Ink Character Reader is used to read special characters printed on documents like cheques etc. These characters are printed in a special magnetic ink which an MICR can read. This process is called magnetic ink character recognition. A cheque has the cheque number, bank name and branch code. This information makes it easier to sort cheques city-wise or branch-wise using Magnetic Ink Character Reader.
Trackball
A trackball is like a mouse. It has a roller ball mounted in a fixed position. The user can spin this roller ball mounted in a fixed position. The user can spin this roller ball in different directions to move the cursor on the screen. It is normally used in air-traffic control room, sonar equipment on a ship or submarine, in computer video games etc.
Output Devices
An output device is an electro-mechanical device, used to convert the information produced by the computer inti a form that a user can understand. As the word ‘output’ suggests, output devices bring information out of a computer. Now we will discuss various types of output devices, such as printer, plotter and LCD projector.
Printer
Printer is used to produce hard copy off the output, called printout. Some printer print only textual information whereas some also print graphics. The quality of a printer is determined by its resolution. Printers differ in terms of technology, speed, cost, and quality of printing.
Printers are classified into two basic categories-impact and non-impact printers.
1. Impact Printers: impact printers are those where there is a mechanical contact between the print head and the paper. These printers transfer the image onto the paper by physically striking a head or a needle against an ink ribbon to make a mark on the paper.
Impact printers are further divided into two categories-line printers and character printers.
Line Printers print only a single line at a time and their printing speed varied from 300-3000 lines per minute approximately.
Character Printers print only a single character at a time. Their printing speed varies from 30-600 characters per second approximately.
Impact printers can be further classified into the following:
Dot Matrix Printers can print character or graphic of any shape and size. These printers print one character at a time. Their speed is measured in characters per second (cps). They were at one time the most popular, low-cost personal computer printers.
Drum Printers are much faster than the dot matrix printers and daisy wheel printers. They print a line in a single operation. However, they are quite loud, produce low quality print and are very expensive.
2. Non-impact Printers: Non-impact printers depend on thermal chemical, laser-beam or inkjet technology for printing. There is no contact between the print head and the surface on which they print. They provide a higher speed in terms of characters per second.
Non-impact printers can be of two typed-inkjet printers and laser printers.
Inkjet Printers are the most common printers found at home even though they are costlier than dot matrix printers. They produce high quality graphics and text printouts.
Laser Printers provide good quality prints and are very fast. However, they are expensive and have a high maintenance cost as compared to other printers.
Plotter
A plotter is an output device used to output high quality graphics, charts, graphics and diagrams. Plotters are used in cartography graphics and design works to produce high precision output such as maps, engineering and architectural drawing etc.
Plotters are of four types-drum plotters, micrographics plotters, inkjet plotters and flatbed plotters.
Drum Plotter uses a drum revolver to move the paper during printing while the pen does the plotting on the paper. Paper is wrapped around a drum which revolves to produce one direction of the plot, while the pen moves to provide the other direction. Thus, the size of the output is limited by the width of the drum but can be of any length.
Micro Graphic Plotter does not use a drum. Paper or any other medium is held on both sides by pinch wheels which help to move the paper back and forth.
Flatbed Plotter consists of a horizontal flat surface on which paper is fixed. A bed or tray holds the paper in a fixed position and a surface arm moves the pen both horizontally and vertically on the paper to produce inked output.
LCD Projector
Liquid crystal display projector takes the input from the computer and shows it on a big screen. It is mainly used to display powerpoint presentations in school, colleges etc.
SOFTWARE
Computer works as per our instructions. A group of instructions is called a program. The set of computer programs that is required to run or operate a computer system is called software. Software can be classified in three type.
System Software
A system software refers to a set of programs which has been written for the proper functioning of the computer system. It manages various tasks, such as controlling different operations, moving data in and out of the computer and executing application programs.
The main functions of system software are:
Ø To increase the efficiency of the hardware of a computer.
Ø To make computer simple and easy to use.
Examples of system software are operating systems like windows, DOS (Disk Operating System) and Linux.
Utility Software
Utility software is a collection of one or more programs that helps the user in system maintenance tasks of routine nature. These software help the users in desk formatting, data compression, data backup, scanning for viruses etc.
Application Software
An application software utilized the capacities of computer directly to a dedicated task. It helps the user to perform a certain type of task. Notepad, Paint, Calculator are some examples of application software. This list is never ending as everyday new application software comes into the market.
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