Computer Software

A set of instruction given to the computer to solve a problem is called software.
Software is also called program.Different software's are used to solve different problems.
A computer works according to the instruction written in software.Software is logical
part of a computer.Software cannot be touched.The hardware cannot perform any task
without software.Software is usually stored on hard disk or CDs.It is loaded from the disk
to RAM as and when required.
Types of Software
The main types of software are system software and application software.
System Software:-
System software is set of programs to control and manage the actual operations of a
computer hardware.It controls the usage and allocation of different hardware components.
It enables application programs to execute properly.It controls the basic operations as follows:
* Saving data on disk
* Making computer to work for us
* printing a documents etc.
Types of System Software
Two types of system software are operating system and utility program.
Operating System
An operating system is a set of programs that manages all computer components operations.
A computer cannot do anything without an Operating system.Operating system must be
installed on every computer.Users interact with the computer through the operating system.
Microsoft Windows and Linux are examples of operating system software.
Utility Programs.
A utility program is a type of system software that is used for effective management of
computer system. the user can use utility program to per maintenance tasks related to
different devices and programs. The utility programs to perform maintenance tasks related
to different devices. The utility programs keep the computer system running smoothly.Anti 
virus and file compression software are examples of utility programs.
Application Software
Application software is used to perform various applications on the computer.It helps a
computer user to perform specific tasks.people use application software according to their
needs.It is also known as application package.package. Different software packages are
used on computer to ease the work.The application software uses the operating system in
order to function. The operating system is the base software.The application software runs
on top of the operating system software.
Categories of Application software
The main categories of application software are follows:
Customized Software:- 
Customized software is a type of application software that is designed for a particular 
customer or organization.It is developed to meet the exact requirements of a particular
customer or organization.A customized software can be developed by single programmer 
or a team of programmers.The cost of customized software is more than package software.
Example:-
A software developed for a particular university is an example of customized software.
Package Software:-
Package software is a type of application software that is developed for sale to the general 
public.It is also known as off-the-shelf software.It enables the people to perform daily
activities.package software is normally developed by expert programmers.
Examples of application software are as follows:
Word Processing:-
word processing software is used to produce letters,applications and other documents.
MS Word is an example of word-processing software.
Spreadsheets:-
Spreadsheet program is used for calculations.It provides worksheets to enter data.A
formulas and built-in functions.It provides the facility to display data using charts and figures.
MS Excel an example of spear sheet software.
Databases
Database is an organized collection of related data that is stored in an efficient and compact
manner.It is used to store information quickly.MS Access and oracle are example of database
software.
Graphics 
Graphics software is used to produce advertisements,posters etc.It can also be used to draw
 pictures and figures. Coreldraw and Photo shop are examples of graphic software.
Communication
Communication software is used to communicate with different people using Internet.The 
communication is of different types.The user can communicate by sending email or voice 
mail. MSN Messenger.Outlook Express,mIRC and Internet Explorer are examples of 
communications software.

Cookies

A cookie is used to maintain information about a user state and information about him/her.
Cookies can be used to store user preferences and user information that can be used across
pages in the website.A cookie is also known as web cookie,browser cookie and HTTP cookie.
A cookie is stored as text strings on the computer.If you forget some thing about your website
cookies help you because,cookies save your information in history of computer.  The browser
returns the cookie to the cookie to the server when the page is referenced again.The most
common use of cookie is store a user ID.A cookie may contain the string such as ID=96352398
Example
The website www.amazon.com uses cookies.The user fills a from with the name and
address to order a book.Amazon assigns an ID,stores user's information with that
ID in its database on the server.It also sends the ID to user's browser as a cookie.
The browser stores ID on hard disk.The browser sends the ID back to the server when
the user visits Amazon again.The server customizes the web page according to the user ID.
Types of Cookies
Cookies can be temporarily or permanent.
1.Temporary cookie:Temporary cookie is also called session cookie.It is temporarily stored
in browser's memory and is deleted when the session ends or the browser's is closed.
2.Permanent cookie:Permanent cookie is also called persistent cookie.It is stored permanent
on computer's hard drive.If it is deleted,it will be recreated when the user visits the website
again.
Uses of Cookies
Cookies are used for different purposes such as follows:
* Most websites use them for personalization  of user preferences.For example,a news
website may allow the user to customize the page to display the news of his interests.The
website stores user preference in cookies.
* Some websites also use cookies to store user,s password.The users do not need to enter
the password  again and again.
*Some websites use cookies to track visits of users and web pages visited by the users.
* Online shopping sites generally use session cookies to keep the track of items in a user's
shopping cart.
* Some websites may use cookies to target advertisement.These sites store a user's interests
and browsing habits in the cookie and display related ads on the pages.
Browser Setting about cookies
The browser can be set to accept cookies as follows:
* The user can set the browser to accept cookies automatically.
* It can be set to prompt the user to accept cookie.
* It can be set to disable the use of cookies altogether.However,the user may not be able
to use many of e-commerrce web sites if cookies are disabled.
Privacy Concerns about Cookies
Webmasters obtain information using the cookies about users IP addresses,browser type,last
pages visited.It allows Web servers to recognize a user who has already  visited the website
from the same computer.It allows the compilation of user profiles and large amounts of data
related to the interests of the user.Advertisers and webmasters are currently using cookies to
develop detailed profiles of users and their browsing habits.Each click on a particular type of
page in a website is added to the profile.The information is primarily used for website design
and placement of banner advertisements.However,this information can be sold for other
commercial purpose that creates a concern to personal.

Email

Email(Electronic Mail)

Email stand for Electronic Mail.It is the exchange of massages and files through Internet.
Messages and files through way of sending messages anywhere in the world.The sender
and receiver may be sent to multiple recipients.Email facility is provided by many Internet
service providers or specialized websites.Yahoo,Hotmail and gmail are examples of
popular email providing websites.
Working of Email:-
An email program is used to create,send and receive emails.It is also known as email 
client.When the user sends an email message,,the computer connects to an email server
and transmits a copy of the message to that server.Email server is a host computer on the 
Internet that is used to send and receive emails.The email server receives the message
and finds out the email server  where that email is to be sent.It connects to that server and
transmits another copy of the message.
Email Attachment:-
An email message can also contain attachments.Attachments is a process of sending
connecting files withemail massage. Any.Any type of file can be attached to email such asdocuments,spreadsheets,audio and video etc.MIME is an Internet protocol that supports
email attachments.It stands for Multi purpose Internet Mail Extension. Different websites
provide Different file size that can be attached with an email message.
Advantages and Uses of Email:-
Some  advantages of email are as follow:
*It is very fast and timely.
*It is very cheap and inexpensive.
*People can send and receive massage anywhere in the world.
*People can share your information among different people.
*It is possible to send and receive email through mobile phone.
*Email gives us the facility to send picture, sounds and videos.
Limitations/Disadvantages of Email:-
Some limitations of email are as follows:
Lack of Privacy:-
email dose not provide high privacy.It passes from one system to other via different
networks.System administrator of a network or a hacker can read the contents of emails.
Junk Email:-
Junk email is an unwanted email.It is also known as spam.A person may send such email
that the receiver dose not want to read.Sometimes,junk email are in such number that it fills
the space of email account.
spreading of Virus:-
Most of the viruses are speared through email messages.Virus can speared if the user opens
an email containing a virus.
No Emotions:-
An email message connote express emotions properly.The receiver cannot view facial
expression or voice of the sender.He may also interpret a humorous message wrongly.
Possible Delay:-
Email is read when the user connects to the Internet and checks email account.An urgent 
message may be ignored or delayed if a person dose not check his email account soon.
Communications Problems:-
E mail may not be delivered successfully due to communication errors.
Email Address:-
Every email has different address.An email address usually has two parts which are
separated by symbol @.These parts are as follows:
*User ID          *Identity of email service
Example:-
myemail@hotmail.com
my email:-
myemail is called user ID.It is used to sign into email service. 
@:-
It is "at" sign.It separates account ID from name of Email service provider.
hotmail.com:-
It indicates the email service provider.