3 What You Will Learn About The purpose of special keys and the most frequently used pointing devicesInput devices used to get audio and digital data into the computerThe characteristics of a monitor’s quality and the various types of monitorsThe two major types of printersThe difference between memory and storage
4 What You Will Learn About The categories of storage devicesThe performance characteristics of hard drivesHow data is stored on both hard and floppy disksThe various optical storage media available for personal computers
5 Input Input is any data entered into the computer’s memory. Types of input include:Data – Unorganized information (words, numbers, images, or sounds) that the computer converts to meaningful informationSoftware – Programs transferred from storage devices to the computer’s memoryCommands – Instructions that tell the computer what to doResponses – Prompts requiring user feedback
6 Input Devices Keyboards Pointing devices Game controllers Scanners Input device captures information and translates it into a form that can be processed and used by other parts of your computer.KeyboardsPointing devicesGame controllersScannersStylusesMicrophonesDigital camerasWeb camsGood Exercise: Ask students if they can name any other input devices. A hard drive can be classified as both an input device and an output device.p Fig. 5-1
7 Input DevicesThe keyboard is the most common input device. Types of keyboards include:Enhanced or Extended keyboard – Typically 101 keys laid out in the QWERTY fashion; connected to the computer by a cableCordless keyboard – Uses infrared or radio wave signalsErgonomic keyboard – Designed to help prevent cumulative trauma disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motionErgonomic KeyboardEnhanced / Extended KeyboardSimNet Concepts Support CD: “Keyboards”p Fig. 5-2
10 Pointing Devices Various pointing devices are available Types of pointing devices:MouseMechanical mouseOptical mouseWireless mouseTrackballTouchpadPointing stickSimNet Concepts Support CD: “Mice”p & P Fig. 5-3 & Fig 5.4
11 Game Controller Game controllers are used mainly to play games Types of gaming devicesGamepadsJoysticksGaming wheelsForce feedp Fig. 5-5
12 Specialized Input Devices Other types of input devices include:ScannersStylusesMicrophonesDigital camerasWeb camsp Fig. 5-6
13 Alternative ScannersFax MachinesScannersFlatbedBarcode reader
14 ScannerScanner is a light sensitive device that helps you copy or capture images, photos, and artwork that exist on paper. Types of scanners include:FlatbedSimNet Concepts Support CD: “Scanners”
15 StylusesStylus is an input device consisting of a thin stick that uses pressure to enter information or to click and pointStyluses are used with:PDAsTablet PCsGraphics tabletsp Fig. 5-6
16 Microphones Microphones are used to input audio Three main types of microphones are:Desktop microphonesHeadsetsDirectional microphonesSpeech recognition is increasingly being included in application software
17 Digital Cameras Digital cameras are used to: Download images to a computerPost pictures to the WebProduce videosResolution is measured in megapixelsHigher the resolution, better the image quality, but the more expensive the cameraSimNet Concepts Support CD: “Digital Cameras”
18 Web CamsWeb cam is a video camera that can be used to take images for uploading to the Web
19 Output DevicesOutput devices take information within your computer and present it to you in a form that you can understandMain output devices:MonitorsPrintersSpeakersSimNet Concepts Support CD:“Overview of Output Devices”
20 Other Types of Pointing Devices Touch ScreenTrackballPointing StickJoystickPenTouch Pad
21 Audio Input Computers can accept input from a microphone. An expansion card called a sound card records and plays back sound files.Sound files contain digitized sound data.Popular sound file formats include:Windows WAVMoving Pictures Expert Group (MPEG)MP2 and MP3Musical Instrument Digital Interface (MIDI)
22 Digital CamerasThe image’s light falls on a charge-coupled device (CCD) which transforms the light’s patterns into pixels (individual dots).Images are stored in the camera using flash memory. The most popular types are CompactFlash and SmartMedia.Photo-editing programs enable the user to edit the images.
23 Digital VideoA video capture board transforms analog video into digital video.Digital video cameras use digital technologies to record video images.A Web cam is a low resolution video camera.Digital video cameraWeb cam
24 Output DevicesOutput devices take information within your computer and present it to you in a form that you can understandMain output devices:MonitorsPrintersSpeakersSimNet Concepts Support CD:“Overview of Output Devices”
25 MonitorsCRTLCDA monitor is a peripheral device which displays computer output on a screen.Screen output is referred to as soft copy.Types of monitors:Cathode-ray tube (CRT)Liquid Crystal Display (LCD or flat-panel)LED: Light Emitting DiodePlasma
26 Cathode-ray tube (CRT) Resemble televisionsUse picture tube technologyLess expensive than a LCD monitorTake up more desk space and use more energy than LCD monitors
27 Liquid Crystal Display (LCD) Cells sandwiched between two transparent layers form imagesUsed for notebook computers, PDAs, cellular phones, and personal computersMore expensive than a CRT monitorTake up less desk space and use less energy than CRT monitorsTypes of LCD monitors:Passive-matrix LCDActive-matrix LCDGas plasma displayField emission display
28 Monitor Specifications Screen size measured as a diagonal line across the screen – from corner to opposite corner (15,17,20)Resolution the number of pixels displayed on the screen (the higher the resolution, the closer together the dots) 600*800Pixels (or picture element) dots that make up the image on your screenDot pitch is the distance between the centers of a pair of like-colored pixelsRefresh rate the speed with which a monitor redraws the image of the screen, and is measured in hertz
29 PrintersA printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
30 Types of PrintersLaserInkjetInkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paperLetter-quality printoutsCost of printer is inexpensive but ink is costlyLaser printer works like a copierQuality determined by dots per inch (dpi) producedColor printers availableExpensive initial costs but cheaper to operate per page
31 Difference Between Dot.Matrx, Inkjet and Laser Printer Dot MatrixVery CheepLess quality20-30 sec-A4Less Maintenance costInkJetMore cost than DotGood quality5-10 Sec-A4High Maintenance costLaserHigh CostExcellent quality1-2 Sec-A4Low Maintenance cost
32 PlotterA plotter is a printer that uses a pen that moves over a large revolving sheet of paper.It is used in engineering, drafting, map making, and seismology.
33 Memory vs. StorageRAM – memoryHard Drive – storageStorage, also known as mass media or auxiliary storage, refers to the various media on which a computer system can store data.Storage devices hold programs and data in units called files.Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.
34 Difference Between Memory & Storage VolatileCheepLess Space(2-8GB)FasterNon VolatileMore costMore Space(1 TB)Slower than Memory
35 Sequential vs. Random Access Storage Hard Disk – random-access storageTape Drive – sequential storageFloppy Disk Drive – random-access storageSequential – Storage devices that read and write data in a serial (one after the other) fashionRandom-Access – Storage devices that read and write data without going through a sequence of locations
36 Storage Technologies: Magnetic and Optical Optical Storage – CD/DVD driveMagnetic StorageMagnetic – Storage devices use disks or tapes that are coated with magnetically sensitive materialOptical – Storage devices that use laser beams to read patterns etched into plastic disks
37 Magnetic Disk StorageSectorA disk is formatted; it is divided into tracks and sectors, and a file allocation table (FAT) is created.Track – circular bandSector – pie shaped sectionCluster – two or more adjacent sectorsFAT – keeps track of specific locations of filesTrackCluster
38 Optical Disk StorageDisk surface magnifiedCross-section of a diskMicroscopic indentations called pits scatter the laser beam’s light. A light-sensing device receives no light from the pits. A signal is sent to the computer corresponding to a 0 in the binary system.Flat, reflective areas, called lands, bounce the light back to the light sensing device, which sends a signal corresponding to a 1.
39 The Storage Hierarchy The three levels of storage hierarchy are: Online storage – Also called primary storage, it is made up of the storage devices that are actively available to the computer system. User action is not required.Near-online storage – Also called secondary storage, it is not readily available to the computer system. The user performs an action, such as inserting a disk, to make it available.Offline storage – Also called tertiary storage or archival storage, it is not readily available to the computer system. Devices such as tape backup units store data for archival purposes.
40 Storage Capacity and Speed Floppy DiskHard DriveCD ROM / DVDCapacity – CD-ROM 650 MB; DVD 17 GBAccess Time – 80 to 800msCapacity – 720 KB to 1.44 MBAccess Time – 100msCapacity – Up to 80 GBAccess Time – 6 to 12msA storage device’s performance is measured by:Capacity – The number of bytes of data that a device can holdAccess Time – The amount of time, in milliseconds (ms), it takes the device to begin reading data
41 Hard Disks Hard disks are high-speed, high-capacity storage devices. PlatterRead/Write headHard disks are high-speed, high-capacity storage devices.They contain metal disks called platters.They contain two or more stacked platters with read/write heads for each side.Hard disks can be divided into partitions to enable computers to work with more than one operating system.
42 Factors Affecting a Hard Disk’s Performance Seek time or positioning performance – How quickly the read/write head positions itself and begins transferring information. It is measured in milliseconds (ms).Spindle speed or transfer performance – How quickly the drive transfers data. It is measured in rotations per minute (RPM).
43 Floppy and Zip Disks and Drives Zip DriveFloppy DriveClick on the picture to see it work.Floppy DiskA disk or diskette is a portable storage medium.High-density floppy disks that are commonly used today store 1.44 MB of data.Disks work with a disk drive.Zip disks store up to 750 MB of data and are not downwardly compatible with floppy disks.
45 CD-ROM Discs and Drives CD-ROM stands for Compact Disc-Read Only Memory.CD-ROM drives can not write data to discs.They are capable of storing 650 MB of data.They are used for storing operating systems, large application programs, and multimedia programs.
46 CD-R and CD-RW Discs and Recorders Discs can be read and written toDiscs can only be written to “once”CD-R drives are capable of reading and writing dataCD-RWDiscs can be read and written toDiscs are erasableDiscs can be written to many timesCD-RW drives are capable of reading, writing, and erasing data
47 DVD-ROM Discs and Drives DVD stands for Digital Video Disc.DVD technology is similar to CD-ROM technology.DVDs are capable of storing up to 17GB of data.The data transfer rate of DVD drives is comparable to that of hard disk drives.DVD-R and DVD-RW drives have the ability to read/write data.