1. Computer
A computer can be simply defined as an electronic machine which can do
the work of computations and data processing .Computer is an electronic
device that takes and as input data based on the instructions stored in its
memory and provides the result of processing to the user by displaying them
on the screen or by printing them using printer. In fact, it can perform a
variety of jobs which are mentioned as under.
 Speedy and accurate calculation.
 Storage of information.
Retrieval of information.
Combining information.
Storing information.
 Processing of information.
Let us study this machine in details…

2. STRUCTURE OF A COMPUTER SYSTEM
A computer system is much more than just the hardware of computer
(Physical components). It consists of following four components :
 Hardware
 Software
 Data
 Users
 DATA
It is a most import ant component of computer system. The hardware
and
Software of computers operates on data.
“Data consists of raw facts and figures on which the computer has to
work
To provides useful results”.
Data without processing has no useful meaning
e.g. 1 , 9, ram abc, *,Sunday 2,4 ,9, is just with no useful meaning

3. Downloading
 Downloading is the process of obtaining a copy of
software or files from a remote location on your
computer with the help of internet . After searching for
the required software in the website , you can
download it on your computer and store it permanently.
For some software's , you have to abide by certain rules
and regulations and follow the instruction.
Generally, there are four types of software you can
download from the internet . These are Demo ware ,
Freeware ,Shareware and Patches/Upgrades.
 Demoware-: This is a crippled version of a retail copy of
software . By crippled we mean that in some way the
functionality of the program has been reduced enough
to make the program marginally useful. T he primary
purpose of demo ware is to let you “test drive” software
before making a decision to purchase it.