1. Computer Skills Preparatory Year 2011-2012 Presented by: L.Obead Alhadreti

2. Last week - Lecture 3  The main parts of the Personal Computer  Computer Software  Types of Computer Software  Software/System Development Process

3. Lecture 4 - Outline  Networks and their advantages  Networks Types  Client and Server  The Internet  The Intranet & Extranet  Main uses of the Internet  Internet Connection

4. Networks and their advantages  Network Definition The network can be defined as a collection of computer connected together with an objective of sharing resources.  Networks Advantages:  Sharing hardware components e.g. printer  Sharing computers software e.g. programs by using servers.  Sharing Information by joining files and folders through the network.  Protecting data and information by using a username and password.

5. Networks Types  Networks Types: The network, according to the distance between the computer can be divided Into: 1. Local Area Network (LAN) is a group of computers connected to each other by cables, distributed in a limited areas e.g. a company.

6. Networks Types 2. Wide Area Network (WAN) is a group of computers connected to each other but for being distributed in a wide areas e.g. branches of company in two city. Communication is done through telephone lines or satellites. 3. Metropolitan Area Network (MAN) is a group of computers connected to each other but for being distributed all over a city.

7. Client and Server  Client a computer connected to the network. Has no authorities in relation to the network. Only use the services introduced by the server.  Server a computer provides services to the clients and control the network.

8. The Internet The network, according to the user access can be divided into:  The definition of the Internet is a collection of various networks that can communicate with one another. International Network = Internet internet is a network which is for public. The communication between the computers is done through a protocol called Transmission Control Protocol/ Internet Protocol (TCP/IP).

9. The Internet  The history of the Internet It all begins during the cold war between the soviet union and the united states. -1957 the soviet union developed a satellite to transfer information. - 1960 ARPA developed ARPA net. - 1969 ARPA net was connected to many American universities. - 1970 The internet was used in Europe. - 1972 electronic email appeared. - 1980 the internet was widely used.

10. The Intranet & Extranet  The Intranet is an internal and local network. Used the technology of internet in an isolated environment. e.g. A special network for the company to exchange information and data, used only by the staff. Used firewall to protect the data. Users need username and password to log ii.  The Extranet is expanded local network.. grant some of the clients the capabilities to use them through secure gates. A collection of intranet networks. e.g. bank to view our bank statement.

11. Main uses of the Internet  The world wide web (WWW) is the most common service. Developed in 1992. by tim breners. it is a huge hyper text documents. Depends on a protocol called Hyper Text Transfer Protocol (HTTP). Used to get information in various forms, e.g. sound, visual, and written form.  The advantages of www pages  Non-linearity  Interactivity  Grpahical interfaces

12. Main uses of the Internet  The electronic mail (e-mail) is one of the most commonly used application. Is an electronic copy of the ordinary mail. It is free. Developed in 1972. used to send messages anywhere in the world. Used a protocol called SMTP. User-name@ server-name Example: AAA@ hotmail.com

13. Main uses of the Internet  File Transfer (FTP) Enable its users to upload and download the files, which help researcher to transfer data through the network. Used File transfer protocol (FTP).  Internet relay chat Enables its users to chat with one another. Can be done by writing, sound, pictures, videos. It assist in distance learning.

14. Internet Connection To connect to the Internet, you will need to: 1. TCP/IP 2. Connection unit e.g. Modem 3. Communication lines 4. Internet services provider (ISP) 5. Internet browser e.g. Internet explorer.

15. Types of Communication lines 1. PSDN PSDN or Public Switched Data Network is simply the technical name for the telephone system in use today. 2. ISDN Stands for "Integrated Services Digital Network." ISDN dates back to 1984, and allows much faster transfer rates than when using modems. Using ISDN, you can transfer 64K or 128K of data per second. 3. Satellites Satellite communications makes it possible for you to make a telephone call or access the internet from almost anywhere on the planet. Very Expensive.

16. Modem  Modem  is advice that transform the analog signals into digital signals and vice versa.  The computer deals with the digital signals while the telephone lines deals with the analog signals.  The modem sends information from your computer across the telephone system.  The modem at the other end of the phone line, converts the signal back into a format that can be used by the receiving computer.

17. Lecture 4 - Outline  Networks and their advantages  Networks Types  Client and Server  The Internet  The Intranet & Extranet  Main uses of the Internet  Internet Connection

18. Lecture 5- Next Week !  IT in society