Thương mại điện tử - Chapter 3: Computer hardware

Computer HardwareChapter3Identify the major types and uses of microcomputer, midrange, and mainframe computer systems.Outline the major technologies and uses of computer peripherals for input, output, and storage.Learning ObjectivesLearning ObjectivesIdentify and give examples of the components and functions of a computer system.Identify the computer systems and peripherals you would acquire or recommend for a business of your choice, and explain the reasons for your selections.What is a Computer?Definition:All computers are systems of input, processing, output, storage, and control components.Case #1: Mobile and Wireless DevicesWhen it comes to wireless technologies used to empower a mobile workforce, the ROI seems to be a minor issue.Cost isn’t the issue – connectivity is.Companies can better manage their costs by using wireless technology to its fullest.Case #1: Mobile and Wireless DevicesIT Department’s ChallengeEnsure that business users have access to solid, secure connections, no matter where they’re working.Must think through how to deliver applications so they can be used on small LCD screens.Case #1: Mobile and Wireless DevicesWhat are some of the benefits that organizations could realize by connecting all of their employees with mobile devices?Are the CIOs in the case saying that ROI is not important when deploying mobile computing devices? Explain your position.Case #1: Mobile and Wireless DevicesThe case suggests that an increasingly popular mobile device is the Blackberry. What is it about the Blackberry that makes it so popular? Check out the Research in Motion website at www.rim.net to help with your answer.Should mobile wireless technologies be bundled together in a generic fashion or should manufacturers allow for customization of mobile devices to be more industry or task specific? Explain.Types of Computer SystemsMicrocomputer SystemsPersonal Computer (PC) – microcomputer for use by an individualProfessional Workstation – a powerful, networked PC for business professionalsLaptop – small, portable PCMicrocomputer SystemsNetwork Server – more powerful microcomputers that coordinate telecommunications and resource sharing in small local area networks and Internet and intranet websitesComputer Terminals – depend on servers for software, storage and processing powerMicrocomputer SystemsNetwork Computers – low-cost, sealed microcomputers with no or minimal disk storage that are linked to the networkInformation Appliances – hand-held microcomputer devicesPC FeaturesMidrange SystemsDefinition:Primarily high-end network servers and other types of servers that can handle the large-scale processing of many business applications.Mainframe SystemsDefinition:Large, fast, and powerful computer systemsSupercomputer SystemsDefinition:Extremely powerful computer systems specifically designed for scientific, engineering, and business applications requiring extremely high speeds for massive numeric computationsHardware Organized by System FunctionsInput Devices convert data into electronic form for direct entry or through a telecommunications network into a computer systemProcessing Components primarily the Central Processing Unit (CPU)Arithmetic-Logic Unit (ALU) - perform arithmetic and logic functions required to execute software instructionsHardware Organized by System FunctionsOutput Devices convert electronic information produced by the computer system into human-intelligible form for presentation to end usersStorage Devices store data and software instructions needed for processingControl Components primarily the CPU’s Control Unit which interprets software instructions and transmits directions that control the activities of the other components of the computer systemComputer Processing SpeedsMillisecond – thousandth of a secondMicrosecond – millionth of a secondNanosecond – billionth of a secondPicosecond – trillionth of a secondComputer Clock SpeedsMIPS – million instructions per secondMegahertz (MHz) – millions of cycles per secondGigahertz (GHz) – billions of cycles per secondThroughputDefinition:Ability of a microprocessor to perform useful computation or data processing assignments during a given period of timeDepends on:Buses – size of circuitry paths that interconnect microprocessor componentsRegisters – that process instructionsCache – high-speed memorySpecialized ProcessorsCase #2: Customer Self-Service KiosksGoal:For airline travelers, the best trips are fast and hassle-free, with limited time spent at the airport.The goal is speeding travelers to their destinations.Case #2: Customer Self-Service KiosksSelf-Service Kiosks Uses:Check in for flightsGet boarding passes for originating or connecting flightsSelect or change seatsRequest to stand by for an upgradeCheck baggageChange flightsInitiate multiparty check-insInternational check-inCollect feesCase #2: Customer Self-Service KiosksBenefits:Help customers shave 5 to 15 minutes off the time they have to stand in lineCornerstone of a broader airport strategy to offer customers more controlCase #2: Customer Self-Service KiosksTechnology:Input video touch screens as the primary user interfacemagnetic stripe card readerProcessing - networked special-purpose microcomputer terminalsOutput - built-in, high-speed thermal printer Case #2: Customer Self-Service KiosksWhat computer system technologies and functions are included in self-service kiosks? What other technologies should be provided? Why? Visit the Kinetics USA website for more details.What is the customer value of self-service kiosks for airline check-ins? What other services should be provided? Take the demo tour of the Delta check-in kiosk at www.delta.com/travel/trav_serv/kiosk to help you answer.Case #2: Customer Self-Service KiosksWhat is the business value of self-service kiosk in the airline industry? Do self-service kiosks give airlines a competitive advantage? Why or why not?What are several other present or potential business applications for self-service networked kiosks? What are their business benefits and limitations? Give several examples.Computer PeripheralsDefinition:Generic name given to all input, output, and secondary storage devices that are part of a computer system, but are not part of the CPU.Peripherals AdviceOnline vs. OfflineOnline – devices are separate from but can be electronically connected to and controlled by a CPUOffline – devices are separate from and not under the control of the CPUInput TechnologiesKeyboardPointing DevicesPen-Based ComputingSpeech Recognition SystemsOptical Scanning Graphical User Interface (GUI)Definition:Icons, menus, windows, buttons, bars, etc used for user selectionPointing DevicesElectronic Mouse – Moving mouse on pad moves cursor on screen. Pressing buttons on mouse activates activities represented by selected icons.Trackball – Stationary device with a roller ball on top used to move cursor on screen.Pointing Stick – Small button-like device which moves cursor in direction of pressure placed on stick.Pointing DevicesTouchpad – Small rectangular touch-sensitive surface which moves the cursor in the direction of finger moves on the pad.Touch Screen – Video display screen that emits a grid of infrared beams, sound waves, or a slight electric current that is broken when the screen is touched.Pen-based ComputingDefinition:Pressure-sensitive layer under slate-like liquid crystal display screen and software that digitizes handwriting, hand printing, and hand drawingSpeech Recognition SystemsDiscrete – user must pause between each spoken wordContinuous – software can recognize conversationally-paced speechOptical ScanningDefinition:Devices that read text or graphics and convert them into digital input for your computerOptical Character Recognition (OCR)Definition:The machine identification of printed characters through the use of light-sensitive devicesOther Input TechnologiesMagnetic Stripe – devices that read data stored in the magnetic stripe on the back of cardsSmart Cards – devices that read a microprocessor chip embedded in a cardOther Input TechnologiesDigital cameras – devices that allow you to capture, store, and download still photos and full motion picturesMagnetic Ink Recognition (MICR) – devices that can read characters printed on source documents with an iron oxide-based inkOutput TechnologiesVideo OutputPrinted OutputVoice ResponseVideo OutputCathode Ray Tube (CRT) – similar to vacuum tubes in televisionLiquid Crystal Display (LCD) – electronic visual displays that form characters by applying an electrical charge to selected silicon crystalsPrinted OutputInkjet Printers – spray ink onto the pageLaser Printers – use an electrostatic process similar to a photocopying machineStorage Trade-OffsBinary RepresentationDefinition:Data are processed and stored in a computer system through the presence or absence of electronic or magnetic signals in the computer’s circuitry or in the media it usesBit vs. ByteBit – binary digit, which can have a value of either zero or oneByte – basic grouping of bits that the computer operates as a single unit, typically eight bitsStorage CapacitiesKilobyte (KB) – one thousand bytesMegabytes (MB) – one million bytesGigabytes (GB) – one billion bytesTerabytes (TB) – one trillion bytesPetabytes (PB) – one quadrillion bytesASCII CodesBinary Number SystemDefinition:Number system used by computers to perform computations since it has only two digitsBinary Number SystemDirect vs. Sequential AccessDirect (or Random) Access – Each storage position has a unique address. Each storage position can be individually accessed without having to search through other storage positions.Sequential Access – Data are recorded one after another in a predetermined sequence. Locating an individual item of data requires searching the recorded data until the desired item is located.Direct vs. Sequential AccessSemiconductor MemoryCharacteristics:SmallFastShock ResistantTemperature ResistantVolatile – contents of memory is lost when power is interruptedUsed for Primary StorageRAM vs. ROMRandom Access Memory (RAM) – each memory position can be both sensed and changedRead Only Memory (ROM) – can be read but not erased or overwrittenFirmwareDefinition:Frequently used programs which are permanently burned into ROM during manufactureMagnetic DisksCharacteristics:FastLarge Reasonably PricedUsed for Secondary StorageTypes of Magnetic DisksFloppy Disks – single disk inside a protective jacketHard Disk Drives – several disks, access arms and read/write heads in a sealed moduleRedundant Arrays of Independent Disks (RAID) - disk arrays of interconnected microcomputer hard disk drivesFormatting DisksHard Disk DrivesMagnetic TapeDefinition:Read/write heads of magnetic tape drives record data in the form of magnetized spots on the iron oxide coating of the plastic tapeOptical DisksOptical DisksBusiness Applications of Optical DisksLong-term archival storage of historical files of document imagesPublishing medium for fast access to reference materials in a convenient compact formComputer video games, educational videos, multimedia encyclopedias and advertising presentationsCase #3: Speech Recognition SoftwareComputerized speech has come a long way since the early 1980s. The technology has become smarter, easier to use, and more integrated with other applications. Such technical advances, plus product introductions that facilitate the development of the technology by mainstream developers, are enabling new uses for automated speech systems.Case #3: Speech Recognition SoftwareDespite the steady advancements to bigger vocabularies, lower error rates, and more natural interfaces, however, speech products have remained specialized tools for niche markets such as PC navigation by the disabled, medical dictation, and tightly constrained customer service interactions.Case #3: Speech Recognition SoftwareBut now, previously stand-alone speech systems are linking up with enterprise systems to access other applications and spawn transactions.Case #3: Speech Recognition SoftwareWhat are the business benefits and limitations of IVR at Verizon? How could their use of IVR be improved? Defend your proposals.What types of business situations would benefit most from IVR technology? Which ones would benefit least? Explain.Case #3: Speech Recognition SoftwareGiven the advancements in voice recognition software over the last 20 years, what types of new applications for IVR do you see in the next 20 years? Give examples and explain.Case #4: Moving to Linux on the MainframeLinux Benefits:Low cost of licensing LinuxRely on a community of users to identify and fix bugsMainframe Benefits:ReliabilitySpeedManagement ToolsCase #4: Moving to Linux on the MainframeServer Consolidation:Leverage the mainframe’s reliabilityKeep support costs lowBest Candidates – infrastructure applicationsWorst Candidates – Windows applications and others with complex GUIs or that perform complicated data analysisCase #4: Moving to Linux on the MainframeTasks:Identify applications to run on the mainframeMigrate applications first to stand-alone servers running LinuxTrain staff in mainframe Linux skillsCase #4: Moving to Linux on the MainframeHow can a mainframe use Linux to replace the equivalent of hundreds of Unix or Windows servers?What are the business benefits and challenges of using Linux on a mainframe to replace Windows or Unix servers? Use WPS and Winnebago to illustrate your answer.Case #4: Moving to Linux on the MainframeWhat business applications are best suited to servers? To mainframes? Explain your reasoning.SummaryMajor types of computers include microcomputers, midrange computers, mainframe computers and supercomputers.A computer is a system of information processing components that perform input, processing, output, storage, and control functions.End of ChapterChapter3