Internet is the global network of computers connected by network cables or satellite signals.
- It is a network of networks so called super network.
- ARPANET (Advanced Research Projects Agency Network) is the world's first operational packet switching network which is predecessor of Internet.
- WWW (World Wide Web) is developed by Tim Berners Lee in 1989 while working at CERN.
- WWW is a communication model used to exchange information over Internet.
- URL (Uniform Resource Locator) specifies the unique address of resources over Internet.
- Search engine is a website that helps users to locate their searched information over world wide web.
E.g. Google, yahoo, bing, baidu, ask.com, AOL, excite, DuckDuckGo, Wolfram Alpha, Yandex, Lycos and Chacha
- A web browser is a software application to access the information on WWW.
E.g. Google Chrome, Firefox, Safari, Internet Explorer and Opera.
Protocol is a standardized set of rules used for network communication. Below are few major protocols.
- TCP - Transfer Control Protocol
- IP - Internet Protocol
- POP - Post Office Protocol
- SMTP - Simple Mail Transfer Protocol
- HTTP - Hypertext Transfer Protocol
- FTP - File Transfer Protocol
- TCP/IP allows to transfer information over Internet, by breaking data into smaller pieces called packets.
- IP address is unique code assigned to each computer. It is of 4 numbers separated by a dot and each number is in the range between 0 to 255. E.g. 192.168.34.12.
- POP allows to receive mails.
- SMTP allows to send mails.
- HTTP protocol allows to access web pages as a connection between web client and web server.
- FTP allows to transfer files from one computer to other.
Email is a service to exchange the messages/information among people over Internet. It is invented by Ray Tomlinson.
- It has limited usage in 1960s and full usage in 1970s.
- Email address is in the form of username@domainname. E.g. firstname.lastname@example.org
- Email addresses are not case sensitive.
- From - indicates sender's email address.
- To - indicates recipient's email address.
- CC (Carbon Copy) - indicates the recipient's email addresses who are to be informed but not a direct recipient.
- BCC (Blind Carbon Copy) - indicates recipent's email addresses but hides recipient email addresses from each other.