Slide 3 What You Will Learn About The purpose of special keys and the most frequently used pointing devices Input devices used to get audio and digital data into the computer The characteristics of a monitor’s quality and the various types of monitors The two major types of printers The difference between memory and storage
Slide 4 What You Will Learn About The categories of storage devices The performance characteristics of hard drives How data is stored on both hard and floppy disks The various optical storage media available for personal computers
Slide 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 information Software – Programs transferred from storage devices to the computer’s memory Commands – Instructions that tell the computer what to do Responses – Prompts requiring user feedback
Input Devices Input device captures information and translates it into a form that can be processed and used by other parts of your computer. Keyboards Pointing devices Game controllers Scanners Styluses Microphones Digital cameras Web cams p Fig. 5-1 Slide 6
Input Devices The 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 cable Cordless keyboard – Uses infrared or radio wave signals Ergonomic keyboard – Designed to help prevent cumulative trauma disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motion p Fig. 5-2 SimNet Concepts Support CD: “Keyboards” Enhanced / Extended Keyboard Ergonomic Keyboard Slide 7
Slide 8 Keyboard Alphanumeric Keys Numeric Keys Function Keys Arrow Keys Combination Keys Keys (Ctrl, Alt, Shift) Special Keys
Types of Input Devices p Fig. 5-2 Slide 9
Pointing Devices Various pointing devices are available Types of pointing devices: Mouse Mechanical mouse Optical mouse Wireless mouse Trackball Touchpad Pointing stick p & P Fig. 5-3 & Fig 5.4 SimNet Concepts Support CD: “Mice” Slide 10
Game Controller Game controllers are used mainly to play games Types of gaming devices Gamepads Joysticks Gaming wheels Force feed p Fig. 5-5 Slide 11
Specialized Input Devices Other types of input devices include: Scanners Styluses Microphones Digital cameras Web cams p Fig. 5-6 Slide 12
Scanner Scanner is a light sensitive device that helps you copy or capture images, photos, and artwork that exist on paper. Types of scanners include: Flatbed SimNet Concepts Support CD: “Scanners” Slide 14
Styluses Stylus is an input device consisting of a thin stick that uses pressure to enter information or to click and point Styluses are used with: PDAs Tablet PCs Graphics tablets p Fig. 5-6 Slide 15
Microphones Microphones are used to input audio Three main types of microphones are: Desktop microphones Headsets Directional microphones Speech recognition is increasingly being included in application software Slide 16
Digital Cameras Digital cameras are used to: Download images to a computer Post pictures to the Web Produce videos Resolution is measured in megapixels Higher the resolution, better the image quality, but the more expensive the camera SimNet Concepts Support CD: “Digital Cameras” Slide 17
Web Cams Web cam is a video camera that can be used to take images for uploading to the Web Slide 18
Output Devices Output devices take information within your computer and present it to you in a form that you can understand Main output devices: Monitors Printers Speakers SimNet Concepts Support CD: “Overview of Output Devices” Slide 19
Slide 20 Joystick Touch Pad Touch Screen Trackball Pointing Stick Pen Other Types of Pointing Devices
Slide 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 WAV Moving Pictures Expert Group (MPEG) MP2 and MP3 Musical Instrument Digital Interface (MIDI)
Slide 22 Digital Cameras The 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.
Slide 23 Digital Video A 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. Web cam Digital video camera
Output Devices Output devices take information within your computer and present it to you in a form that you can understand Main output devices: Monitors Printers Speakers SimNet Concepts Support CD: “Overview of Output Devices” Slide 24
Slide 25 Monitors A 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) Cathode-ray tube (CRT) Liquid Crystal Display (LCD or flat-panel) Liquid Crystal Display (LCD or flat-panel) LED: Light Emitting Diode Plasma CRT LCD
Slide 26 Cathode-ray tube (CRT) Resemble televisions Use picture tube technology Less expensive than a LCD monitor Take up more desk space and use more energy than LCD monitors
Slide 27 Liquid Crystal Display (LCD) Cells sandwiched between two transparent layers form images Used for notebook computers, PDAs, cellular phones, and personal computers More expensive than a CRT monitor Take up less desk space and use less energy than CRT monitors Types of LCD monitors: Passive-matrix LCD Active-matrix LCD Gas plasma display Field emission display
Slide 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*800 Pixels (or picture element) dots that make up the image on your screen Dot pitch is the distance between the centers of a pair of like- colored pixels Refresh rate the speed with which a monitor redraws the image of the screen, and is measured in hertz
Slide 29 Printers A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
Slide 30 Inkjet Laser Types of Printers Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper Letter-quality printouts Cost of printer is inexpensive but ink is costly Laser printer works like a copier Quality determined by dots per inch (dpi) produced Color printers available Expensive initial costs but cheaper to operate per page
Slide 32 Plotter A 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.
Slide 33 Hard Drive – storage RAM – memory Memory vs. Storage Storage, 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.
Difference Between Memory & Storage Memory Volatile Cheep Less Space(2-8GB) Faster Storage Non Volatile More cost More Space(1 TB) Slower than Memory Slide 34
Slide 35 Sequential vs. Random Access Storage Sequential – Storage devices that read and write data in a serial (one after the other) fashion Random-Access – Storage devices that read and write data without going through a sequence of locations Tape Drive – sequential storage Hard Disk – random-access storage Floppy Disk Drive – random-access storage
Slide 36 Storage Technologies: Magnetic and Optical Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material Magnetic Optical – Storage devices that use laser beams to read patterns etched into plastic disks Optical Magnetic Storage Optical Storage – CD/DVD drive
Slide 37 Track Sector Cluster Magnetic Disk Storage A disk is formatted; it is divided into tracks and sectors, and a file allocation table (FAT) is created. Track – circular band Sector – pie shaped section Cluster – two or more adjacent sectors FAT – keeps track of specific locations of files
Slide 38 Optical Disk Storage Microscopic 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. Cross-section of a disk Disk surface magnified
Slide 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.
Slide 40 Floppy DiskHard DriveCD ROM / DVD Capacity – 720 KB to 1.44 MB Access Time – 100ms Capacity – Up to 80 GB Access Time – 6 to 12ms Capacity – CD-ROM 650 MB; DVD 17 GB Access Time – 80 to 800ms Storage Capacity and Speed A storage device’s performance is measured by: Capacity – The number of bytes of data that a device can hold Access Time – The amount of time, in milliseconds (ms), it takes the device to begin reading data
Slide 41 Platter Read/Write head Hard Disks Hard 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.
Slide 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).
Slide 43 Floppy and Zip Disks and Drives A 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. Zip Drive Floppy Drive Click on the picture to see it work. Floppy Disk
Performance Enhancement for HD Slide 44
Slide 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.
Slide 46 CD-R and CD-RW Discs and Recorders CD-R Discs can be read and written to Discs can only be written to “once” CD-R drives are capable of reading and writing data CD-RW Discs can be read and written to Discs are erasable Discs can be written to many times CD-RW drives are capable of reading, writing, and erasing data
Slide 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.