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Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e©

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Presentation on theme: "Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e©"— Presentation transcript:

1 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e© 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 4

2 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 2

3 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 3

4 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Digital Computers use digital signals0s and 1s, off and on. All the data that a computer processes is a series of 0s and 1s. Each signal is a bit. Analog But most phenomena in life are analog. Analog signals use wave variations. Sound, light, and temperature are analog forms. Traditional TV and radio use analog signals. Humans vision operates in analog mode. But analog data can be converted into digital form. Even though digital data is not as exact as analog data, it is easier to manipulate. 4

5 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e For data transmission over telephone lines and cables, modems are needed to convert analog data into digital data that computers can use. Modem is short for modulate/demodulate. Modems modulate (convert) a computers digital data to analog data, transmit it, then demodulate (reconvert) it back to digital data for the receiving computer. 5

6 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 6

7 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Converting Reality to Digital Form: Tape recorders, voices, and musical instruments are analog; CDs are digital To burn a CD, the digital recording equipment must convert from analog to digital 7

8 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 8

9 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e A network is a system of interconnected computers, telephones, and/or other communications devices that can communicate with one another and share data Benefits of Networks Share peripheral devices, such as printers, scanners, disk drives Share programs and data Better communications, including Access to shared databases 9

10 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Some disadvantages of networks: Expense: The initial set up cost of a computer network can be high depending on the number of computers to be connected and the number of connecting devices and NICs. Security Issues: If a computer is on a network, a computer hacker can get unauthorized access by using different tools. Rapid Spread of Computer Viruses: If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting affected, too. Dependency on the Main File Server: If the main file server of a computer network breaks down, the entire system can become useless. 10

11 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Main types of networks A wide area network (WAN) is a communications network that covers a wide geographic area, such as a country or the world. The best example of a WAN is the Internet. A metropolitan area network (MAN) is a communications network covering a city or a suburb. Many cellphone systems are MANs. A local area network (LAN) connects computers and devices in a limited geographic area, such as one office, one building, or a group of buildings close together. Philadelphia network is an example of LAN. 11 (continued)

12 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 12

13 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e How Networks Are Structured: 1. Client/Server Consists of clients, which are computers that request data, and servers, which are computers that supply data. 2. Peer-to-Peer (P2P) All computers on the network are equal and communicate directly with one another, without relying on servers 13

14 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 14

15 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Intranets & Extranets: use the Internet as their base Intranetsuse infrastructure and standards of the Internet and the web, but for an organizations internal use only Extranetssimilar to intranets but allows use by selected outside entities, such as suppliers 15

16 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Network linking devices: Switch A device that connects computers to a network; sends data only to intended recipients BridgeInterface device that connects same type of networks GatewayInterface device that connects dissimilar networks RouterDevice that directs messages among several networks, wired and/or wireless BackboneMain Internet highway that connects all networks in an organization; includes switches, gateways, routers, etc. 16

17 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Network topologies: Bus, Ring, Star, Mesh Bus – all nodes are connected to a single wire or cable Ring – all nodes are connected in a continuous loop Star – all nodes are connected through a central host Mesh – messages sent to the destination can take any possible shortest, easiest route to reach its destination. There must be at least two paths to any individual computer to create a mesh network. (Wireless networks are often implemented as a mesh, and the Internet is a mesh.) 17

18 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 18 Bus Network

19 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 19 Ring Network

20 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 20 Star Network

21 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Ethernet The Ethernet communications protocol is embedded in software and hardware devices intended for building a local area network (LAN), and it is commonly used in star topologies. 21

22 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e 22

23 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Problem: Internet was begun to foster collaboration among universities and scientists. They trusted one another. No security was built into the Internet. Problem: The Internet is open-access and is used by criminals who take advantage of the lack of built-in safeguards. Problem: Most people connect to the Internet and use their computers in LANs. All it takes is one computer on a LAN that has been compromised for all computers on it to be vulnerable to malware and other threats. 23

24 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Cyberthreats Denial of Service Attacks Consist of making repeated requests of a computer or network device, thereby overloading it and denying access to legitimate users Used to target particular companies or individuals Viruses Deviant program that hides in a file or a program on a disk, flash memory drive, in an , or in a web link that causes unexpected effects such as destroying or corrupting data 24

25 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Cyberthreats (continued) Trojan Horses Programs that pretend to be a useful program such as a free game or a screensaver but that carry viruses or malicious instructions that damage your computer or install a backdoor or spyware Backdoors and spyware allow others to access your computer without your knowledge Worms A program that copies itself repeatedly into a computers memory or disk drive May copy itself so much it crashes the infected computer 25

26 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Cyberthreats (continued) How they spread Via attachments By infected disks and flash drives By clicking on infiltrated websites By downloading infected files from websites From one infected PC on a LAN to another 26

27 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Cybervillains Hackers are either Computer people who enjoy learning about programming and computers People who gain unauthorized access to computers or networks, often for fun or just to see if they can 27

28 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Online Safety Use antivirus software, and keep it current Install a firewall to monitor network traffic and filter out undesirable types of traffic and undesirable sites Dont use the same password for multiple sites Dont give out any password information Use robust passwords: Minimum 8 characters with letters, numbers, characters 4cats is not a good password; is safer 28

29 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Online Safety (continued) Install antispyware software Back up your data, so if your PC is attacked and must be reformatted, you can restore your data Never download from a website you dont trust Consider biometric authentication 29

30 Introduction to Information Technology: Your Digital World © 2013 The McGraw-Hill Companies, Inc. All rights reserved.Using Information Technology, 10e Online Safety (continued) Biometrics: science of measuring individual body characteristics Used in security devices Examples; hands, fingerprints, iris recognition, face recognition, voice recognition Now available on laptops 30


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