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1Lecturer: Dalia Mirghani Saadabi. 2 A set of computers connected together so that they can communicate is called a computer network. This involves installing.

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Presentation on theme: "1Lecturer: Dalia Mirghani Saadabi. 2 A set of computers connected together so that they can communicate is called a computer network. This involves installing."— Presentation transcript:

1 1Lecturer: Dalia Mirghani Saadabi

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3 A set of computers connected together so that they can communicate is called a computer network. This involves installing network cards in each computer. Each computer is then connected through cabling to a central device called a hub. Operating systems contain components that are dedicated to the task of enabling computers to communicate over a network. This software makes use of special rules of communication called protocols. The most commonly used protocol for establishing and maintaining communication across a network is called TCP/IP or Transmission Control Protocol / Internet Protocol. 3Lecturer: Dalia Mirghani Saadabi

4 There are two types of network interconnection: 1) Networks on which all computers have equal status are called peer-to-peer networks. 2) Certain computers provide services to other computers, they are called servers. The computers that make use of the services or servers are called clients. A network such as this is called a client server network. 4Lecturer: Dalia Mirghani Saadabi

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6 1. LAN A LAN or Local Area Network is a group of computers within the same building, or within a group of buildings that are in close proximity, that are connected together. 2. WAN A WAN or Wide Area Network is a group of widely dispersed computers that are connected together. These could be across the same town, or across a country or even across the world. 6Lecturer: Dalia Mirghani Saadabi

7 Internet The internet is the collection of all computers across the world which can access each other in some way. The links between computers might include telephone, fiber optic cable, radio, microwave or satellite. Some of its main uses: Provide access to and share information and databases. Transfer and share files between computers. Facilitate business transactions. Share resources. Promote scientific co-operation between research institutions. Provide a communications channel for the military. 7Lecturer: Dalia Mirghani Saadabi

8 Intranet An intranet is similar to the Internet in operation. However, it is limited to an organization. Users may browse computers within an intranet using a browser but will usually not be able to access the wider Internet. An intranet can be thought of as a private Internet. 8Lecturer: Dalia Mirghani Saadabi

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10 The World Wide Web, or simply Web, is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet. The Web uses Hypertext Markup Language or HTTP protocol, which is the only language that spoken over the Internet to transmit data. The Web also utilizes browsers, such as Internet Explorer or Firefox, to access Web documents called Web pages that are linked to each other via hyperlinks. Web documents also contain graphics, sounds, text and video. 10 Lecturer: Dalia Mirghani Saadabi

11 A modem is a device connected between a computer and a telephone line. Its function is to convert the digital signals of the computer into a form suitable for transmission over a telephone line. It must also do the reverse and convert the telephone line signals into a form suitable for the computer. 11Lecturer: Dalia Mirghani Saadabi

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13 A special device is needed to move the data from the computer or mobile device through the transmission media to the access provider. Some computers have wireless and network cards built into them instead of modems: 1.A wireless card: Is used to provide connectivity via mobile computers. 2. A network card: Which is installed into a computer, enables a direct connection to a network. 3. USB cellular modem: Is a wireless adapter that connects a laptop to a cellular telephone system for data access and transfer. Lecturer: Dalia Mirghani Saadabi 13

14 Lecturer: Dalia Mirghani Saadabi14 A wireless card A network cardUSB cellular modem

15 Using the world wide web  Using Web browser: A web browser is the software program that is used to display Web pages on the World Wide Web, as Internet explorer and Firefox.  Internet search engine: Is an application, which helps users to locate Web sites containing useful information and references. To search Information :  A user types the description of the information using the user interference of the search engine.  The search engine then searches the requested information on the WWW and returns the results to the user. 15Lecturer: Dalia Mirghani Saadabi

16 This section will focus on a specific search engine such as Google chrome. Enter your URL into your web browser location bar. Press Enter or click Search. The secret of using a search engine such as Google in choosing the best key words or phrases to locate useful web sites. 16Lecturer: Dalia Mirghani Saadabi

17 Some Popular Internet Search Engines 17Lecturer: Dalia Mirghani Saadabi

18 Special Medical Search Engines…

19 Medical Search Engines: Medical search engines are search engines which are specialized in medical information, researches, news and so on. Here are some examples of the most popular medical search engines… 19Lecturer: Dalia Mirghani Saadabi

20 1- iMediasearch2- Lecturer: Dalia Mirghani Saadabi 20

21 3- OmniMedicalSearch Lecturer: Dalia Mirghani Saadabi21

22 Most Popular medical website: Lecturer: Dalia Mirghani Saadabi22

23 Online Encyclopedia & Libraries www.oxfordhandbooks. com Lecturer: Dalia Mirghani Saadabi23

24 (Medical dictionary) 24Lecturer: Dalia Mirghani Saadabi

25 Information security refers to all the procedures which are used to protect information for deliberate or accidental misuse or dissemination Technically, it refers to the maintenance of the integrity of information. There are a number of procedures companies and persons can take to protect their information. 25Lecturer: Dalia Mirghani Saadabi

26 1.Security procedures: Information should be classified on the basis of its sensitivity. Access rights to this information should be limited to those who need to know. 2.Physical procedures: Physical access to mainframes should be restricted to operators and systems administrators. Desktop and laptop computers are very vulnerable to theft. A simple procedure is to only allow authorized people access to offices. The use of security cameras can also act as a deterrent. 26Lecturer: Dalia Mirghani Saadabi

27 3. Software procedures: Information can be stolen, altered or deleted without the computer being physically removed. The information may even be accessed across the Internet. a) Firewalls: It is a computer program that is installed on a computer that connects a network to the Internet. The firewall analyses the packets that pass in and out of the network. b) Access rights: Access rights can refer to both physical and software. Software rights refer to the level of access different users have to different levels of data and information. 27Lecturer: Dalia Mirghani Saadabi

28 c) Password policies: They can be required for access to a computer system or a group of files or a single file. 28Lecturer: Dalia Mirghani Saadabi

29 A computer virus is a program that is deliberately created to cause annoyance or alter or delete data. Trojan: A Trojan (or Trojan horse) is a virus that hides itself inside another legitimate program. When the program is used, the virus is released and can begin its work of replication and annoyance or damage. Worm: A Worm is a program that replicates itself over and over in the computer's memory until the computer can barely function. One of the signs of invasion by a worm is the slowness of computers. 29Lecturer: Dalia Mirghani Saadabi

30 Spread of computer viruses: Viruses are spread in a number of ways: –Downloads from the Internet. –Pirated software. –Exchange of diskettes. –In attachments to emails and in emails themselves. –In documents. 30Lecturer: Dalia Mirghani Saadabi

31 Anti-virus software: Anti-virus software scans files for pieces of code, called signatures, which it recognizes as part of a virus. Updating anti-virus software mostly involves updating the signatures file. When a virus is detected, the software will attempt to remove the virus. This is called cleaning or disinfecting. 31Lecturer: Dalia Mirghani Saadabi

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