1. © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Chapter 7A Networking and Information Systems

2. 2 2 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Learning Objectives 7.1Describe the benefits of using networks, the common types of networks, and network hardware 7.2 Define the term information system, and list the basic structural components of any information system 7.3 Identify types of information systems, and explain the basic purpose of each 7.4Describe fault-tolerant computing, as related to information systems, and explain the purpose of electronic data interchange

3. 3 3 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Computer Networks Network : a set of hardware, software, and media systems used to connect computers togetherNetwork : a set of hardware, software, and media systems used to connect computers together Benefits of networks:Benefits of networks: –Users easily share data, programs, and hardware –Make it easy to back up data –Open up new ways to communicate

4. 4 4 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Types of Networks Common types of networksCommon types of networks –Local area network (LAN) : a data communication system consisting of multiple devices –Wide area network (WAN) : the connection of two or more central computers or LANs –Intranet : an internal version of the Internet the contains only the company's private information –Extranet : shares intranet resources with people outside of the organization

5. 5 5 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Network Media Network media are the means used to link together a computer network’s nodesNetwork media are the means used to link together a computer network’s nodes Types of media:Types of media: –Twisted-pair cable: normally consists of four pairs of wires –Coaxial cable: has two conductors with an insulator between –Fiber-optic cable: a thin strand of glass that transmits pulsating beams of light rather than electric current –Wireless networks: use radio or infrared signals that travel through the air to transmit data

6. 6 6 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Network Topologies Packets: pieces of a message broken down in to small unitsPackets: pieces of a message broken down in to small units –Data moves through the network in packets –Most packets have two parts: Header: first part; contains information needed by the networkHeader: first part; contains information needed by the network Payload: the actual data being transmitted between the nodesPayload: the actual data being transmitted between the nodes Topology: logical layout of the cables and devicesTopology: logical layout of the cables and devices

7. 7 7 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Types of Topologies Bus topology: arranges the network nodes in a series, linking one node to the next via a single cableBus topology: arranges the network nodes in a series, linking one node to the next via a single cable –A terminator is attached at the start and end points Star topology: all nodes are connected to a hub wire and communicate through itStar topology: all nodes are connected to a hub wire and communicate through it Ring topology: connects the network’s nodes in a circular chainRing topology: connects the network’s nodes in a circular chain Mesh topology: a cable runs from every computer to every other computerMesh topology: a cable runs from every computer to every other computer

8. 8 8 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Network Hardware Linking devices:Linking devices: –Repeaters: prevent attenuation when packets are traveling long distances –Hubs: provide multiple ports for connecting nodes

9. 9 9 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Network Hardware Linking devices:Linking devices: –Bridges: connect two LANs or two segments of a LAN –Switches: devices that are aware of the exact address so they can send packets to the correct destination –Routers: devices that store the routing information –Gateways: create connections between different types of networks

10. 10 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Standards Each LAN is governed by a protocolEach LAN is governed by a protocol –An agreed-upon message format for transmitting data between two devices Physical transmission standards:Physical transmission standards: –Ethernet: Most installations use an Ethernet star topology with either twisted-pair or fiber-optic cables –Fast Ethernet: available using the same topology as Ethernet, but can achieve speeds up to 100 Mbps –Gigabit Ethernet: version of Ethernet technology that supports data transfer rates of 1 gigabit per second

11. 11 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Options for Data Communication Modems with telephone linesModems with telephone lines Broadband accessBroadband access –Broadband: can transmit data faster than standard dial-up connection using a modem –Asynchronous transfer mode: a more efficient way to send data over a single network Wireless networksWireless networks –Wi-Fi: popular standard for wireless networking –Wireless access point: where one or more computers can connect to the network

12. 12 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Information Systems Information system: a system for acquiring, storing, organizing, using, and sharing data and informationInformation system: a system for acquiring, storing, organizing, using, and sharing data and information Basic componentsBasic components –Physical means for storing data –Physical means, methods, procedures for distributing and sharing information –Procedures for handling information to ensure its integrity –Rules regarding data use and distribution

13. 13 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Types of Information Office automation system: Uses computers and/or networks to perform operations needed in an office environmentOffice automation system: Uses computers and/or networks to perform operations needed in an office environment –Off-the-shelf applications: software available for purchase by anyone Transaction processing system: system that handles the processing and trackingTransaction processing system: system that handles the processing and tracking of transactions –Transaction: A complete information operation

14. 14 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Types of Information Management information system: set of software tools that enables managers to gather, organize, and evaluate informationManagement information system: set of software tools that enables managers to gather, organize, and evaluate information Decision support system: collects and reports certain types of data to help managers make better decisionsDecision support system: collects and reports certain types of data to help managers make better decisions Expert system: type ofExpert system: type of information system that performs analytical tasks

15. 15 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Fault-Tolerance Mission-critical systems must run without failure or with nearly instant recovery from failureMission-critical systems must run without failure or with nearly instant recovery from failure Fault-tolerant computers are able to continue operation even when components and programs failFault-tolerant computers are able to continue operation even when components and programs fail –Redundant computers have multiple hardware systems performing the same task at the same time –Redundant array of independent disks (RAID): Storage system that links an array of disk drives so they act as a single disk

16. 16 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. RAID Striping (or RAID 0): gives user rapid access by spreading data across several disksStriping (or RAID 0): gives user rapid access by spreading data across several disks Mirrored (RAID 1) system: Data written to two or more disks simultaneouslyMirrored (RAID 1) system: Data written to two or more disks simultaneously Striping-with-parity (RAID 5): data is spread over multiple disks and the system stores parity information for reconstructing data if necessaryStriping-with-parity (RAID 5): data is spread over multiple disks and the system stores parity information for reconstructing data if necessary

17. 17 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Scalable and Interoperable Systems Scalability: The capability to provide increasing amounts of computing power, storage, and softwareScalability: The capability to provide increasing amounts of computing power, storage, and software Interoperability: Ability of each information system to work with the other information systemsInteroperability: Ability of each information system to work with the other information systems

18. 18 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Data Data warehousingData warehousing –Huge data warehouses can store data from thousands or millions of transactions Data miningData mining –Analysis uncovers trends, opportunities, threats Data scrubbing:Data scrubbing: –process of safeguarding against erroneous or duplicate data

19. 19 © 2013 by the McGraw-Hill Companies, Inc. All rights reserved. Data Transactions Organizations that send large volumes of information need a more efficient method than e-mailOrganizations that send large volumes of information need a more efficient method than e-mail Electronic data interchange (EDI): A standardized electronic transfer of information between companies over networksElectronic data interchange (EDI): A standardized electronic transfer of information between companies over networks –Can occur over extranets or the Internet –Not a way to transfer funds