Output and Storage Copyright 2003 Paradigm Publishing Inc

Topics What is Output? Storage Devices and Media Display Devices Magnetic Storage Devices and Media Printers Optical Storage Devices Speakers and Voice Output Storage Devices for Large Computer Systems Other Types of Output On the Horizon Topics Copyright 2002, Paradigm Publishing Inc. 3 -2

What is Output? processed data that can be used or stored hard copy permanent

Types of Output TEXT characters or numbers AUDIO any sound including speech and music

Output Devices and Media Output Device any hardware device that makes information available to a user Output Medium any material on which information is recorded Topics Copyright 2002, Paradigm Publishing Inc. 3 -5

Display Devices Most common soft-copy output mechanism Designed to operate with input devices – graphics adapter converts digital signals into text Most are capable of displaying information in thousands of different colors – monochrome = only one color Size is measured diagonally – from one corner to the diagonally opposite corner Topics Copyright 2002, Paradigm Publishing Inc. 3 -6

Cathode Ray Tube (CRT) Monitors Most common type – large, sealed glass tube housed in a plastic case – front of the tube is the screen, cable at the rear of monitor plugs into graphics adapter board, electric cord into outlet RGB – Red, Green, Blue – contained in each dot of phosphor material on screen – three dots make up a pixel – electron beam moves back and forth across rear of screen causing dots on front to glow Video card converts digital signals to analog signals Topics Copyright 2002, Paradigm Publishing Inc. 3 -7

Flat-Panel Displays Smaller, lighter, thinner, and consume less power Liquid crystal display (LCD) – liquid crystals are sandwiched between sheets of material – electric current passes through crystals and causes them to twist – effect blocks some light waves and allows others to pass through – uses digital signals Topics Copyright 2002, Paradigm Publishing Inc. 3 -8

Flat-Panel Displays…/2 Passive-matrix display • also called dual-scan display • single transistor controls an entire column or row • viewing the screen requires the user to look directly at it Active-matrix display • also called thin-film transistor (TFT) display • separate transistors control each color pixel • allows viewing from any angle • provides higher resolutions • more expensive, uses more power Topics Copyright 2002, Paradigm Publishing Inc. 3 -9

Monitor Performance and Quality Factors Amount of RAM Refresh Rate Resolution Topics Copyright 2002,

Amount of RAM Graphics adapters usually have their own built-in video memory Determines the number of colors, resolution, speed of signal Number of colors determined by number of bits used by the card to store information about each pixel (bit depth) True color – any graphics device using at least 24 bits – more than 16 million unique colors can be represented Topics Copyright 2002, Paradigm Publishing Inc. 3 - 11

Resolution number of pixels in the display determines quality more pixels = better image

Refresh Rate Images become weaker as the current used to produce them diminishes – causes screen to flicker Refresh rate refers to the number of times per second the screen is redrawn to avoid flickering Topics Copyright 2002, Paradigm Publishing Inc. 3 - 13

Monitor Ergonomics – the study of the interaction between humans and the equipment they use Monitor adjustments – – position brightness contrast height and width of images – antiglare screen Topics Copyright 2002, Paradigm Publishing Inc. 3 - 14

Wearable Displays Allow mobile workers to perform without having to stop to use a computer (handsfree) Data and information are displayed on a headset-mounted full-color video console Topics Copyright 2002, Paradigm Publishing Inc. 3 - 15

Television Displays NTSC converter converts the computer’s digital signal into an analog signal that can be displayed on a television screen HDTV (high-definition television) newer type of technology uses digital signals Topics Copyright 2002, Paradigm Publishing Inc. 3 - 16

Printers Most common device for hard-copy output Format – portrait – printed page is taller than wide – landscape – printed page is wider than tall Categories – impact – strikes an inked ribbon against the paper – nonimpact – uses electricity, heat, laser technology, or photographic techniques to form images Three types include a range of printers that vary in quality of output and printing speed Topics Copyright 2002, Paradigm Publishing Inc. 3 - 17

Dot-Matrix Printers Tiny dots form images Print head strikes inked ribbon, deposits on page Resolution measured in dpi – draft or letter quality Print head contains pins – more pins = higher quality Prints one character at a time – speed measured by cps Capable of printing multipart forms Topics Copyright 2002, Paradigm Publishing Inc. 3 - 18

Ink-Jet Printers Spray thousands of tiny droplets of electrically charged ink to form images

Photograph Printers Unique ink-jet printers Designed to print highquality color photographs Very versatile Some contain a slot for a SIM card – medium used with some digital cameras Topics Copyright 2002, Paradigm Publishing Inc. 3 - 20

Laser Printers Exceptional quality Mechanism reads characters and sends to laser device Laser sends light signals through mirrors in the drum, creating tiny dots of light Dots create magnetic fields on drum (matches shape) which attracts toner power Toner pressed onto paper as drum rotates Topics Copyright 2002, Paradigm Publishing Inc. 3 - 21

Plotters Produce specialized kinds of large-sized, highquality printing Image consists of a series of tightly packed tiny dots Toner is fused onto paper when electrically charged wires come into contact with specially coated paper Topics Copyright 2002, Paradigm Publishing Inc. 3 - 22

Speakers and Voice Output Topics Copyright 2002, Paradigm Publishing Inc. 3 - 23

Other Types of Output Facsimile (fax) machines – can send and receive copies of a document through telephone lines • send - scans the page, converts to digitized data, transmits • receive – converts digitized data into original form, print or store – many computers come with board that fits into an expansion slot (requires fax program) Multifunction devices (MFDs) – provide a variety of capabilities including scanning, copying, printing, faxing – less desktop space; all functions lost if inoperable Topics Copyright 2002, Paradigm Publishing Inc. 3 - 24

Storage Devices and Media Permanent storage consists of devices and media used for permanent recordings – also called secondary, auxiliary, or external storage File types – almost all information stored must be in a file with a unique name – operating system poses restrictions on the format of file names – file extension identifies the type of file • characters follow file name and a period • some automatically entered by operating system or program Topics Copyright 2002, Paradigm Publishing Inc. 3 - 25

Secondary Storage Devices Consist of two main parts – storage device • hardware component that houses a storage medium – storage medium • where data is recorded Usually built into a PC system Two main types – magnetic – optical Topics Copyright 2002, Paradigm Publishing Inc. 3 - 26

Magnetic Storage Devices and Media Categories – permanent – attached to system unit (e. g. , hard disk) – removable – can be removed/replaced (e. g. , floppy disk) How stored data is accessed – sequentially – in the order in which data was stored – directly – in any order, randomly Access time – time spent locating a file Data transfer rate – speed at which data is transferred from memory or storage device Work by applying electrical charges to iron filings on the surface medium – either magnetized (1 -bit) or not magnetized (0 -bit) Topics Copyright 2002, Paradigm Publishing Inc. 3 - 27

Floppy Disks and Disk Drives Disks is a thin, circular Mylar wafer between two sheets of special cleaning tissue inside a plastic case Data is stored along tracks and sectors – track – a numbered concentric circle – sector – a numbered section or portion; group = cluster Computer maintains a file directory of the file name, size, and sector in which the file begins – called a file allocation table (FAT file) Higher-capacity floppy disks – Super. Disk, Zip®, Hi. FD Topics Copyright 2002, Paradigm Publishing Inc. 3 - 28

How a Floppy Disk Drive Works Topics Copyright 2002, Paradigm Publishing Inc. 3 -

Formatting a Floppy Disk Must be formatted by manufacturer or user How a disk is formatted is determined by disk drive and operating system Disk surface is arranged into – tracks – sectors – clusters Topics Copyright 2002, Paradigm Publishing Inc. 3 - 30

Handling a Floppy Disk Topics Copyright 2002, Paradigm Publishing Inc. 3 - 31

Hard Disks and Hard Drives Consist of – one or more rigid metal platters (disks) – disks mounted on a metal shaft in a container – an access mechanism Sealed to prevent contamination Fixed or interchangeable – Jaz® cartridge Usually preformatted – can be reformatted Topics Copyright 2002, Paradigm Publishing Inc. 3 - 32

Comparing Floppy Disks and Hard Disks Floppy Disks üstorage capacity: megabytes üspin only when data is being stored or accessed Hard Disks ügreater storage capacities: gigabytes üoperates much faster; rotates faster ücontinues spinning while computer is in operation Topics Copyright 2002, Paradigm Publishing Inc. 3 - 33

Tape Cartridges and Tape Drives One of the first types Used mainly for – backing up the contents of a hard drive – archiving large amounts of data Small plastic housing containing a magnetically coated ribbon of thin plastic Tape drive is used to read and write data Relatively inexpensive Sequential-access type of storage Topics Copyright 2002, Paradigm Publishing Inc. 3 - 34

Optical Storage Devices Optical disk – also called compact disk (CD) – a plastic disk that is 4. 75 inches in diameter Optical disk drive – can read almost any kind of data recorded Data stored along a single track in sectors – spirals outward from the center to the outer edge Available in a variety of formats – not necessarily compatible with one another Topics Copyright 2002, Paradigm Publishing Inc. 3 - 35

Types and Storage Capacities of Optical Disks Topics Copyright 2002, Paradigm Publishing Inc. 3

Storage Devices for Large Computer Systems Magnetic Disk pack – mounted inside a disk drive – metal shaft extends through center of vertically aligned disks – provides direct access Magnetic tape – removable reels – contains tracks that extend the full length of the tape – sequential access Optical WORM – write once, read many disks – mainly found in mainframe applications – high-capacity – usually only readable by the drive on which they were written Topics Copyright 2002, Paradigm Publishing Inc. 3 - 37