HARDWARE & SOFTWARE

1: INTRODUCTION TO COMPUTER

HARDWARE & SOFTWARE

 What is a Computer?

A  computer  is  an  electronic  device  that  takes  in  data,  processes  them

according to the given instructions and produces information that is useful

to people. 

Computer is made up of:

 

Hardware 

A  computer's  hardware  consists  of  electronic  devices;  the  parts  you  can

see and touch.

The term "device" refers to any piece of hardware used by the computer,

such as a keyboard, monitor, modem, mouse, Printer, etc.

  Software

Software is a set of electronic instructions that tells the computer how

to do certain tasks. A set of instructions is often called a program.

When a computer is using a particular program, it is said to be running

or executing the program.

The two most common types of programs are system software and

application software.

Systems Software 

System software exists primarily for the computer itself, to help

the computer perform specific functions.

One major type of system software is the operating system (OS).

All computers require an operating system. 

The OS tells the computer how to interact with the user and its

own devices.

 

Common operating systems include Windows, the Macintosh OS,

OS/2, and UNIX.

Application Software 

Application software tells the computer how to accomplish tasks the

user requires, such as creating a document or editing a graphic

image.

Some important types of application software are:

Word processing programs  

Spreadsheet software  

Database management    

Presentation programs  

Graphics programs      

Networking software   

Web design tools and browsers 

Internet applications  

Communications programs   

Utilities     

Entertainment and education   

Multimedia authoring

Computer Types

Computers can be generally classified by size and power. Some of the

Computer types include:

  Supercomputer - Supercomputers are the most powerful computers that

are normally used for problems requiring complex calculations. Because of

their  size  and  expense,  supercomputers  are  relatively  rare.

Supercomputers are used by universities, government agencies, and large

businesses. Although some supercomputers are single computer systems,

most  are  comprised  of  multiple  high  performance  computers  working  in

parallel as a single system. The best known supercomputers are built by

Cray Supercomputers. 

  Mainframe -In  the  early  days  of  computing,  mainframes  were  huge

computers that could fill an entire room or even a whole floor! As the size

of  computers  has  diminished  while  the  power  has  increased,  the  term

mainframe  has  fallen  out  of  use  in  favor  of  enterprise  server.  You'll  still

hear the term used, particularly in large companies to describe the huge

machines processing millions of transactions every day. 

Mainframe  computers  can  support  hundreds  or  thousands  of  users,

handling  massive  amounts  of  input,  output,  and  storage.  Mainframe

computers are used in large organizations where many users need access

to  shared  data  and  programs.  Mainframes  are  also  used  as  e-commerce

servers, handling transactions over the Internet.

  Minicomputer - Minicomputers  are  smaller  than  mainframes  but  larger

than microcomputers thus minicomputers fall in between microcomputers

(PCs)  and  mainframes  (enterprise  servers).  Minicomputers  are  normally

referred  to  as  mid-range  servers  now.  Minicomputers  usually  have

multiple  terminals  and  can  be  used  as  network  servers  and  Internet

servers. 

Microcomputer - Microcomputers are more commonly known as personal

 computers  (PC).  The  term  "PC"  is  applied  to  IBM-PCs  or  compatible

computers. The personal computer (PC) defines a computer designed for

general  use  by  a  single  person.  While a  Mac  is  a  PC,  most  people  relate

the term with systems that run the Windows operating system. PCs were

first  known  as  microcomputers  because  they  were  a  complete  computer

but  built  on  a  smaller  scale  than  the  huge  systems  in  use  by  most

businesses

Laptop  -  Also  called  notebooks,  laptops  are  portable  computers  that

integrate the display, keyboard, a pointing device or trackball, processor,

memory  and  hard  drive  all  in  a  battery-operated  package  slightly  larger

than an average hardcover book. 

Palmtop - More  commonly  known  as Personal Digital Assistants (PDAs),

palmtops  are  tightly  integrated  computers  that  often  use  flash  memory

instead of a hard drive for storage. These computers usually do not have

keyboards  but  rely  on  touch-screen  technology  for  user  input.  Palmtops

are  typically  smaller than  a  paperback  novel,  very  lightweight  with  a

reasonable  battery  life.  A  slightly  larger  and  heavier  version  of  the

palmtop is the handheld computer. 

RAM and ROM(Storage section)

 There are two kinds of Memory

 RAM –Random Access Memory (MM)

(this is used for storing programs that are currently

running and data that is being processed)

 ROM –Read Only Memory

(its contents are PERMANENTLY etched into the

memory chip at the manufacturing stage. It is

used –for example –to load the bootstrap loader

(the program that loads as soon as you start the

machine)

RAM

Random Access memory

Main Memory

Stores info about applications that

are open and data 

VOLATILE –

When you switch off the machine, it

disappears!!!

ROM

Read only memory

Non-Volatile (does not change)

Programs that are necessary for the

computer to run

Boot up program

Introduction to Input devices

These are devices used to enter data into  a computer. Let us see the main input

devices used in a computer.

a)  Keyboard: It is an input device used to type in information. It has keys for the

letters of the alphabet as well as keys for numbers, alphabet and other keys,

which perform specific instructions.

b)  Mouse : A mouse is a pointing device about the size of palm. It is a small plastic

box with buttons on top and a ball underneath. When a user rolls the mouse

across a flat surface, the ball rolls and a marker or mouse pointer which

appears on the visual display unit moves in the direction of the mouse’s

movement. Pressing the buttons on the mouse gives instructions to the

computer.

c)  Microphone: Microphone is also an input device as it converts our voice signals

into digital signals and feeds them to the computer.

d)  Scanner : Scanner is an input device used to feed/input a photograph or any

other existing physical image such as a drawing, sketch etc into the computer. 

e)  The scanner is a photocopier- like device that scans an image and sends the

image into the computer.

f)  Joystick : This is an input device used to move the cursor or any other object

on to the visual display unit. It is usually used with video games for moving a

car or plane. A button on top of the joystick sends commands to the computer.

Introduction to Output devices

a)  Monitor: The Monitor is a television like output device used to show the result

of any processing done by the computer. Results of an operation can be shown

as text, numbers, or graphic image such as charts, graphs, figures etc. Monitors

are available in many different sizes. Like Black and white and color TVs,

monitors are available in multicolor and in single color (monochrome).

b)  Printer:  The Printer is an output device used to print the result of any

processing done by the computer on paper. It produces printed copies of text

or graphics on paper. The printer is used to get a “Hard Copy” of the results

i.e. it provides permanent output (which can be viewed, filed and used at a

later stage) on the paper. (Unlike the printer, the monitor provides us with a

soft copy of results, i.e. the result being displayed on the monitor is not

permanent. The moment output is changed or the power supply to the monitor

is switched off, results are lost.)

c)  Speakers: The Speaker is an output device through which we can hear all the

audio results produced by the computer.