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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