Computer Skills 1400 TQN Level 1 Chapter 7 and 8 Input/Output and Storage

Input Devices Output Devices Storage Devices

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

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

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 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. Keyboards Pointing devices Game controllers Scanners Styluses Microphones Digital cameras Web cams Good 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. 5.130 Fig. 5-1

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 Ergonomic Keyboard Enhanced / Extended Keyboard                                                                 SimNet Concepts Support CD: “Keyboards” p. 5.131 Fig. 5-2

Keyboard Alphanumeric Keys Combination Keys Keys (Ctrl, Alt, Shift) Function Keys Arrow Keys Combination Keys Keys (Ctrl, Alt, Shift) Special Keys

Types of Input Devices                                                                 p. 5.131 Fig. 5-2

Pointing Devices Various pointing devices are available Types of pointing devices: Mouse Mechanical mouse Optical mouse Wireless mouse Trackball Touchpad Pointing stick SimNet Concepts Support CD: “Mice” p. 5.132 & P. 5.133 Fig. 5-3 & Fig 5.4

Game Controller Game controllers are used mainly to play games Types of gaming devices Gamepads Joysticks Gaming wheels Force feed                                 p. 5.134 Fig. 5-5

Specialized Input Devices Other types of input devices include: Scanners Styluses Microphones Digital cameras Web cams p. 5.135 Fig. 5-6

Alternative Scanners Fax Machines Scanners Flatbed Barcode reader

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”

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. 5.135 Fig. 5-6

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                                                                                                                                    

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”

Web Cams Web cam is a video camera that can be used to take images for uploading to the Web

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”

Other Types of Pointing Devices Touch Screen Trackball Pointing Stick Joystick Pen Touch Pad

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)

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.

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. Digital video camera Web cam

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”

Monitors CRT LCD 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) Liquid Crystal Display (LCD or flat-panel) LED: Light Emitting Diode Plasma

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

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

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

Printers A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.

Types of Printers Laser Inkjet 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

Difference Between Dot.Matrx, Inkjet and Laser Printer Dot Matrix Very Cheep Less quality 20-30 sec-A4 Less Maintenance cost InkJet More cost than Dot Good quality 5-10 Sec-A4 High Maintenance cost Laser High Cost Excellent quality 1-2 Sec-A4 Low Maintenance cost

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.

Memory vs. Storage RAM – memory Hard Drive – 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 Volatile Cheep Less Space(2-8GB) Faster Non Volatile More cost More Space(1 TB) Slower than Memory

Sequential vs. Random Access Storage Hard Disk – random-access storage Tape Drive – sequential storage Floppy Disk Drive – 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

Storage Technologies: Magnetic and Optical Optical Storage – CD/DVD drive Magnetic Storage Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material Optical – Storage devices that use laser beams to read patterns etched into plastic disks

Magnetic Disk Storage Sector 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 Track Cluster

Optical Disk Storage Disk surface magnified Cross-section of a disk 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.

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.

Storage Capacity and Speed Floppy Disk Hard Drive CD ROM / DVD Capacity – CD-ROM 650 MB; DVD 17 GB Access Time – 80 to 800ms Capacity – 720 KB to 1.44 MB Access Time – 100ms Capacity – Up to 80 GB Access Time – 6 to 12ms 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

Hard Disks Hard disks are high-speed, high-capacity storage devices. Platter Read/Write head 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.

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).

Floppy and Zip Disks and Drives Zip Drive Floppy Drive Click on the picture to see it work. Floppy Disk 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.

Performance Enhancement for HD

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.

CD-R and CD-RW Discs and Recorders 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

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.