sim - mc leod ch05

© 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e RManagement Information Systems, 10/e Raymond McLeod and George Schell aymond McLeod and George Schell

11

Management Management Information Systems, Information Systems,

10/e10/e

Raymond McLeod and George Raymond McLeod and George Schell Schell

© 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e RManagement Information Systems, 10/e Raymond McLeod and George Schell aymond McLeod and George Schell

22

Chapter 5Chapter 5

Computing and Computing and Communications Resources Communications Resources

© 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod and George Schell

3

Learning ObjectivesLearning Objectives

► Know the various computer components.Know the various computer components.► Know about personal computing devices.Know about personal computing devices.► Understand the implications of the rapid Understand the implications of the rapid

advances in information and communication advances in information and communication technologies.technologies.

► Be familiar with input and output resources.Be familiar with input and output resources.► Recognize how different storage media Recognize how different storage media

differ and the advantages of each.differ and the advantages of each.


4

Learning Objectives (Cont’d)Learning Objectives (Cont’d)

► Know the advantages of prewritten software.Know the advantages of prewritten software.► Understand the different computer Understand the different computer

networking strategies.networking strategies.► Understand how communications over the Understand how communications over the

public telephone system and networks differ.public telephone system and networks differ.► Know about network protocols.Know about network protocols.► Distinguish between intranets, extranets, and Distinguish between intranets, extranets, and

the Internet.the Internet.


5

Hardware & ProcessorsHardware & Processors

►MainframesMainframes are large computers used are large computers used for centralized information systems.for centralized information systems.

►MicrocomputersMicrocomputers or or PCsPCs are computers are computers used by one person.used by one person.

►Processor (CPU)Processor (CPU) is where data is where data processing is performed.processing is performed.

►Processor speedProcessor speed is measured by the is measured by the # of cycles that occur per second.# of cycles that occur per second.


6

ProcessorsProcessors

►MHzMHz stands for stands for millions of cycles per millions of cycles per secondsecond..

►WordWord is the measure of how many bits is the measure of how many bits can be moved with one cycle of the can be moved with one cycle of the processor.processor.

►Word sizeWord size is how many characters, is how many characters, “A”, can be moved in a single cycle of “A”, can be moved in a single cycle of the processor.the processor.

►PowerPower is affected by both word size & is affected by both word size & processor speed.processor speed.


7

Table 5.1 Major Computer Table 5.1 Major Computer ComponentsComponents


8

Memory & StorageMemory & Storage

►MemoryMemory ( (primary storage or RAMprimary storage or RAM) ) is the storage area on the computer’s is the storage area on the computer’s circuit board.circuit board. VolatileVolatile Extremely fastExtremely fast

►Fixed storageFixed storage is permanently is permanently installed in the computer.installed in the computer.

►Removable storageRemovable storage media – tape, disk, media – tape, disk, CD, DVD, USB flash drive, etc.CD, DVD, USB flash drive, etc.


9

Figure 5.2 MotherboardFigure 5.2 Motherboard


10

Input DevicesInput Devices

►Human-captured dataHuman-captured data refers to input refers to input captured by a person typing on a captured by a person typing on a keyboard, clicking a mouse, speaking into keyboard, clicking a mouse, speaking into a microphone, or a similar interaction.a microphone, or a similar interaction.

►Machine-captured dataMachine-captured data is data is data captured by an electronic or mechanical captured by an electronic or mechanical device.device.

►Point-of-sale terminalsPoint-of-sale terminals are scanners are scanners used in retail stores.used in retail stores.


11

Output DevicesOutput Devices

►MonitorMonitor Screen resolution, size 17-19’’ diagonals.Screen resolution, size 17-19’’ diagonals. Graphic user interface (GUI).Graphic user interface (GUI).

►PrintersPrinters Lasers are like copier machines.Lasers are like copier machines. Ink-jets spray ink.Ink-jets spray ink.

►Multimedia is the use of more than 1 Multimedia is the use of more than 1 medium at a time.medium at a time.


12

Personal Computing DevicesPersonal Computing Devices

►Cell phones with interactive messaging Cell phones with interactive messaging & video& video

►Smart cell phones are phones that Smart cell phones are phones that perform tasks associated with PCs i.e. perform tasks associated with PCs i.e. BlackBerry 7270, Treo 650.BlackBerry 7270, Treo 650.

►Global Systems for Mobile Global Systems for Mobile Communications (GSM)Communications (GSM) digital digital cellular phone protocol.cellular phone protocol.


13

Home NetworksHome Networks

►Home computer networks assess the Home computer networks assess the Internet via Internet via cable modemscable modems or or DSL DSL modemsmodems..

►Setup usually requires the modem, Setup usually requires the modem, network card(s), wireless router.network card(s), wireless router.

►Wireless security uses Wireless security uses Wired Wired equivalent privacyequivalent privacy ( (WEPWEP) which ) which encrypts the data transferred between encrypts the data transferred between the computer & wireless router.the computer & wireless router.


14

Home Computing SecurityHome Computing Security

►UpdatesUpdates for OS an application for OS an application software.software. For security & efficiency.For security & efficiency. Microsoft UpdateMicrosoft Update..

►HackersHackers are people who try to break are people who try to break into computer systems in order tointo computer systems in order to Gather information;Gather information; Deny the owner access to his resources;Deny the owner access to his resources; Delete files;Delete files; Disrupt the use by the owner.Disrupt the use by the owner.


15

Home Computing Security Home Computing Security (Cont’d)(Cont’d)

►VirusesViruses are small computer programs are small computer programs that replicate by inserting themselves that replicate by inserting themselves into computer resources such as into computer resources such as programs or files.programs or files.

►WormsWorms are self-contained files or are self-contained files or programsprograms Does not have to attach to program or file.Does not have to attach to program or file. Can delete, change files, send e-mails, and Can delete, change files, send e-mails, and

cause problems. cause problems.


16

Home Computing Security Home Computing Security (Cont’d)(Cont’d)

►Denial-of-service attackDenial-of-service attack is when the is when the user is denied access to the services of user is denied access to the services of the computer because it is overwhelmed the computer because it is overwhelmed with e-mail.with e-mail.

►Antivirus softwareAntivirus software – Norton, MacAfee, – Norton, MacAfee, etc. Keep virus definitions updatedetc. Keep virus definitions updated

►SpywareSpyware – Microsoft Defender, Lavasoft – Microsoft Defender, Lavasoft Ad-Aware, etc. Free from Microsoft.Ad-Aware, etc. Free from Microsoft.


17

SoftwareSoftware

►System softwareSystem software ( (OSOS) performs ) performs certain tasks that all computers require.certain tasks that all computers require. Hardware interfaces, device drivers.Hardware interfaces, device drivers. Manage computer’s processes.Manage computer’s processes. OS – Windows XP, Unix, Mac OS X, Linux.OS – Windows XP, Unix, Mac OS X, Linux.

►Application softwareApplication software processes the processes the user’s data.user’s data.

►Prewritten application softwarePrewritten application software is is produced by suppliers and sold to users.produced by suppliers and sold to users.


18

Application SoftwareApplication Software

►Custom application softwareCustom application software is is when programmers for the business when programmers for the business write the software.write the software.

►User-written softwareUser-written software in in End-User End-User ComputingComputing is created by the user, is created by the user, such as Excel Macros, Access Wizards.such as Excel Macros, Access Wizards.

►User-friendly softwareUser-friendly software is computer is computer software that is simple & intuitive to software that is simple & intuitive to use.use.


19

CommunicationsCommunications

►ProtocolProtocol is the specification for is the specification for formatting data to be transferred formatting data to be transferred between communications equipment.between communications equipment.

►Public connectionsPublic connections Telephone modemsTelephone modems Integrated Services Digital Network (ISDN)Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL)Digital Subscriber Line (DSL)


20

Table 5.4 Connecting to the Table 5.4 Connecting to the InternetInternet


21

Communications (Cont’d)Communications (Cont’d)

►PacketPacket is a piece of the total data to be is a piece of the total data to be communicated, includes sender & communicated, includes sender & receiver addresses.receiver addresses.

►Cable modemsCable modems connect to the Internet connect to the Internet via coaxial cable.via coaxial cable.

►Asynchronous transfer mode (ATM)Asynchronous transfer mode (ATM) Improve data transmission rates.Improve data transmission rates. Increased speed.Increased speed.


22

Private LinePrivate Line

►CircuitCircuit is a connection that is always is a connection that is always connected.connected.

►Private linePrivate line is a circuit that is always is a circuit that is always open to your communication traffic.open to your communication traffic. T-1T-1 line over 1.5 Mbps; line over 1.5 Mbps; T-3 T-3 at 43 Mbps.at 43 Mbps. MultiplexedMultiplexed is when the line is broken is when the line is broken

into separate lanes of communication. into separate lanes of communication.


23

Virtual Private NetworksVirtual Private Networks

► Virtual Private Networks (VPNs)Virtual Private Networks (VPNs) allow allow you to use the security & speed of a private you to use the security & speed of a private line but still use the low-cost Internet.line but still use the low-cost Internet.

► Tunneling softwareTunneling software establishes the set of establishes the set of intermediary locations of the telephone intermediary locations of the telephone equipment that will host a given data equipment that will host a given data communications transfer.communications transfer.

► Privacy is attained because the tunnel is not Privacy is attained because the tunnel is not established unless the sending & receiving established unless the sending & receiving computers authenticate one another.computers authenticate one another.


24

Communications - NetworksCommunications - Networks

► Open Systems Interconnection (OSI)Open Systems Interconnection (OSI) standard architecture for network standard architecture for network connections established by the connections established by the ISOISO..

► TerminalTerminal is a device that has no storage or is a device that has no storage or processor; it allows for entering & displaying processor; it allows for entering & displaying data for the computer.data for the computer.

► Systems Network Architecture (SNA)Systems Network Architecture (SNA) is is a protocol for large computers; it polls other a protocol for large computers; it polls other computers connected by the network for computers connected by the network for transfers.transfers.


25

Table 5.5 OSI Reference Table 5.5 OSI Reference ModelModel


26

Networks (Cont’d)Networks (Cont’d)

►Token ringToken ring is a is a peer-to-peer peer-to-peer protocolprotocol that allows each computer to that allows each computer to act as its own controller.act as its own controller.

►EthernetEthernet is an open protocol for peer- is an open protocol for peer-to-peer communications.to-peer communications. IEEEIEEE endorses endorses

►Data transmission crashData transmission crash is when is when two peer computers try to send data two peer computers try to send data at the same time.at the same time.


27

Figure 5.11 Token Ring Protocol Figure 5.11 Token Ring Protocol Example Example


28


►Data packetData packet is a piece of the total data is a piece of the total data to be communicated, combined with the to be communicated, combined with the address of the destination computer, the address of the destination computer, the sending computer, and other control sending computer, and other control information.information.

►Transmission Control Transmission Control Protocol/Internet ProtocolProtocol/Internet Protocol ( (TCP/IPTCP/IP)) TCPTCP conducts communication over the conducts communication over the

network.network. IPIP handles the packets so they can be routed. handles the packets so they can be routed.


29


►IP addressIP address is a four-part set of is a four-part set of numbers (each from 0 to 255), numbers (each from 0 to 255), separated by periods.separated by periods.

►Network interface card (NIC)Network interface card (NIC) is used is used to attach a device to the to attach a device to the communications medium.communications medium.

►Local Area Networks (LANs)Local Area Networks (LANs) is a is a group of computers and other devices group of computers and other devices that are connected together by a that are connected together by a communications medium.communications medium.


30

Table 5.6 Communications Table 5.6 Communications Network HardwareNetwork Hardware


31


►Medium used by LANs can be copper Medium used by LANs can be copper wire, wireless, fiber-optics, or other wire, wireless, fiber-optics, or other media.media.

►LANs join computers that are LANs join computers that are physically located together.physically located together. Same room or building.Same room or building. Total distance is less than ½ mile.Total distance is less than ½ mile. 60 ft. between devices.60 ft. between devices.


32


►Metropolitan area network (MAN)Metropolitan area network (MAN) is a network that has a physical is a network that has a physical distance limit of roughly 30 miles.distance limit of roughly 30 miles.

►Wide are networks (WANs)Wide are networks (WANs) are are used to connect computers and other used to connect computers and other devices when the distance exceeds devices when the distance exceeds the constraints of LANs & MANs.the constraints of LANs & MANs. Uses common carrier, public telephone Uses common carrier, public telephone

system.system. WANs have been replaced by the Internet. WANs have been replaced by the Internet.


33

Internet, Intranet & ExtranetInternet, Intranet & Extranet

►InternetInternet is just a collection of networks is just a collection of networks that can be joined together; Public.that can be joined together; Public.

►IntranetIntranet uses the same network protocols uses the same network protocols as the Internet but limits accessibility to as the Internet but limits accessibility to computer resources to a select group of computer resources to a select group of persons in the organization.persons in the organization.

►ExtranetExtranet is when the intranet is expanded is when the intranet is expanded to include users beyond the firm; Trusted to include users beyond the firm; Trusted customers & business partners.customers & business partners.


34

Convergence of Computing & Convergence of Computing & CommunicationsCommunications

►Computing devices & communications Computing devices & communications devices are now incorporating features devices are now incorporating features of the other into themselves.of the other into themselves.

►Voice over Internet ProtocolVoice over Internet Protocol ( (VoIPVoIP) ) is the routing of voice communications is the routing of voice communications over the Internet as if they were digital over the Internet as if they were digital communications.communications. WWW.SKYPE.COMWWW.SKYPE.COM – free software – free software


35

Mainframe ComputerMainframe Computer


36

Personal Computer (PC)Personal Computer (PC)


37

PC SystemPC System


38

Static RAM / SRAM Dinamic RAM / DRAM

EDORAM (Extended Data Out RAM )

72 pin

SDRAM 168 pin

PROM

EPROM

EEPROM

MemoryMemory


39

Hard disk

Removable StorageRemovable Storage

Floppy disk

Floppy drive

CD

Flash disk


40

Cylinder, sector, track pada harddisk


41

Hard disk layout


42

Input DeviceInput Device

Keyboard

Mouse


43

MonitorMonitor


44

Printer & PlotterPrinter & Plotter

Printer Dot Matrik

Printer Ink JetPlotter

sim - mc leod ch05

Education

e raymond mcleod

george schell

computer systems

global systems

e mail

computer resources

computer wireless router

small computer programs