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CHAPTER 4 Hardware applications for Education CHAPTER 4 Hardware applications for Education.

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1 CHAPTER 4 Hardware applications for Education CHAPTER 4 Hardware applications for Education

2 The System Unit Box-like case that houses the electronic components of the computer used to process data All computers have a system unit Sometimes called the chassis What is the system unit?

3 Processor Memory module Processor Memory module Expansion cards Sound card Modem card Video card Network interface card Ports and Connectors Processor Memory module Expansion cards Sound card Processor Memory module Expansion cards Sound card Modem card Processor Memory module Expansion cards Sound card Modem card Video card Processor Memory module Expansion cards Sound card Modem card Video card Network interface card Processor The System Unit What are common components inside the system unit?

4 The System Unit What is the motherboard? Also called the system board Main circuit board in the system unit Contains many electronic components

5 Central Processing Unit What is the central processing unit (CPU)? Interprets and carries out the basic instructions that operate a computer Most devices communicate with the CPU in order to carry out a task Also called the processor

6 What is a personal computer processor? The single processor chip found in personal computers Sometimes called a microprocessor Processors identified by Manufacturer Model name or model number Central Processing Unit Pentium ® 4 Celeron Duron Athlon

7 Central Processing Unit What are the components of the central processing unit (CPU )? CPU Arithmetic/ Logic Unit (ALU) Control Unit

8 CPU Arithmetic/ Logic Unit (ALU) Central Processing Unit What is the control unit? Control Unit The control unit repeats a set of four basic operations: Fetch – obtain a program instruction or data item from memory Decode - translate the instruction into commands Execute - carry out the command Store - write the result to memory A component of the CPU that directs and coordinates most of the operations in the computer

9 Together the four operations of the CPU comprise a machine cycle Also called an instruction cycle Execution time (e-time) – time it takes to execute and store e-time Instruction time (i-time) - time it takes to fetch and decode i-time Central Processing Unit What is a machine cycle?

10 Central Processing Unit A student enters a math problem into the memory of the computer Step 1: The control unit fetches the math problem from memory Step 2: The control unit decodes the math problem and sends it to the ALU Step 3: The ALU executes the math problem Step 4: The results of the math problem are stored in memory The result in memory displays on the screen of the monitor What is a machine cycle? Together the four operations of the CPU comprise a machine cycle

11 CPU Control Unit What is the arithmetic/logic unit (ALU)? Central Processing Unit.and..not..or. Component of the CPU Performs arithmetic, comparison, and logical operations Performs the execution part of the machine cycle Arithmetic/ Logic Unit (ALU)

12 Data Representation How do computers represent data? Most computers are digital Computers are electronic devices powered by electricity, which has only two states, on or off Computers recognize only two discrete states: on or off on off

13 Data Representation What is the binary system? Binary Digit (bit) Electronic Charge Electronic State A number system that has just two unique digits, 0 and 1 A single digit is called a bit (binary digit) A bit is the smallest unit of data the computer can represent By itself a bit is not very informative The two digits represent the two off and on states

14 Data Representation What is a byte? 8-bit byte for the number 3 8-bit byte for the number 5 8-bit byte for the capital letter T Eight bits are grouped together to form a byte 0s and 1s in each byte are used to represent individual characters such as letters of the alphabet, numbers, and punctuation

15 Data Representation What are two popular coding systems to represent data? American Standard Code for Information Interchange (ASCII) Extended Binary Coded Decimal Interchange Code (EBCDIC) Sufficient for English and Western European languages Unicode often used for other languages

16 Central Processing Unit What is the system clock? Synchronizes all computer operations Each tick is a clock cycle Faster clock speed means the CPU can execute more instructions each second Clock speed (clock rate) measured in megahertz (MHz) and gigahertz (GHz) MHz - one million ticks of the system clock GHz – one billion ticks of the system clock

17 Step 2: An electronic signal for the letter T is sent to the system unit Step 3: The signal for the letter T is converted to its ASCII binary code ( ) and is stored in memory for processing Step 4: After processing, the binary code for the letter T is converted to an image on the output device Data Representation How is a character sent from the keyboard to the computer? Step 1: The user presses the letter T key on the keyboard

18 Memory What is memory? operating system and other system software that control the usage of the computer equipment application programs that carry out a specific task data being processed by application programs Three basic items stored in memory Temporary storage place for data, instructions, and information Consists of one or more chips on the motherboard or some other circuit board

19 Memory How is memory measured? Size of memory is measured by the number of bytes available Kilobyte - 1,024 bytes Megabyte - one million bytes

20 Volatile Memory Loses its contents when the computer's power is turned off volatile memory Loses its contents when the computer's power is turned off Memory What are the two types of memory in the system unit? nonvolatile memory Does not lose its contents when the computer s power is turned off

21 Memory Memory chips that can be read from and written to by the processor and other devices When the computer starts, operating system files are loaded from a hard disk into RAM What is random access memory (RAM)? As additional programs and data are requested, they also load from storage into RAM Most RAM is volatile

22 Storage (hard disk) RAM Step 3: When you quit Word, RAM may be used to store another program or data. The program is removed from the screen and the operating system s user interface redisplays. Step 1: When your computer is running, certain operating system files are in RAM. Shown here is the operating system s user interface. Step 2: When you start a word processing program such as Word, the program loads into RAM from a hard disk. As you create a document, it is in RAM and displays on your screen. Step 4: When you start a spreadsheet program such as Excel, the program loads into RAM from a hard disk. As you create a spreadsheet, it is in RAM and displays on your screen. Memory How are applications transferred in and out of RAM? Step 5: When you quit Excel, RAM may be used to store another program or data. Excel is removed from your screen and the operating system s user interface redisplays.

23 Memory What is a memory module? single inline memory modules (SIMMs) Rambus ® inline memory module (RIMM) Small circuit board with RAM chips, which are smaller in size than processor chips Inserts into the motherboard Three types: SIMMS, DIMMS, and RIMMS dual inline memory modules (DIMMs)

24 Memory What is a memory module? dual inline memory module (DIMM) memory chip RAM chips usually reside on a small circuit board which inserts into motherboard

25 Memory What is read-only memory (ROM)? BIOS (basic input/output system) Stored on ROM Sequence of instructions the computer follows to load the operating system and other files when you first turn on the computer Nonvolatile Contents not lost when the computer is turned off Memory chips that contain data, instructions, or information that is recorded permanently Data can only be read, cannot be modified

26 Expansion Slots and Expansion Cards What is an expansion slot? An opening, or socket, where a circuit board can be inserted into the motherboard Used to add new devices or capabilities to the computer Other terms for a circuit board include card, expansion card, expansion board, board, adapter card, adapter, interface card, add-in, and add-on

27 Modem card also called an internal modem Expansion Slots and Expansion Cards What are four common types of expansion cards? Network interface card (NIC) also called a network card Sound card Video card also called video adapter or graphics card

28 Expansion Slots and Expansion Cards The computer automatically can configure cards and other devices as you install them What is Plug and Play?

29 Used on notebook and other mobile computers Credit card-sized device used to add capabilities to mobile computer Standards developed by Personal Computer Memory Card International Association (PCMCIA) Expansion Slots and Expansion Cards What is a PC card?

30 Ports What is a port? keyboard USB mouse telephone line in game port monitor svideo out network printer (parallel port) cable TV speaker serial port microphone telephone line out FM reception Used to connect external devices to the system unit Port is the interface, or point of attachment, to the system unit Most located on the back of the system unit

31 Ports What are the different types of connectors?

32 Ports What is a serial port? serial transmission of data DB-9 female connector byte representation for number 3 ( ) byte representation for number 5 ( ) DB-9 male connector byte representation for number 1 ( ) Transmits one bit of data at a time Used to connect devices that do not require fast transmission rates mouse keyboard modem Two common types 25-pin 9-pin

33 Ports What is a parallel port? byte representation for number 1 byte representation for number 3 byte representation for number 5 DB-25 male connector DB-25 female connector Connects devices that can transfer more than one bit at a time Usually used for printers Two newer types EPP (Enhanced Parallel Port) ECP (Extended Capabilities Port) IEEE 1284 is a standard that specifies how older and newer peripheral devices transfer data to and from a computer

34 Ports What is a universal serial bus port (USB)? Can connect up to 127 different peripheral devices with a single connector type Supports newer peripherals Supports hot plugging and Plug and Play

35 Ports How are multiple USB devices connected? Computer with USB port Daisy Chain Devices connected together outside the system unit in a chain device 3 device 1 device 4 USB hub Plugs into the USB port on the computer Contains multiple USB ports Computer with USB port device 2 USB hub device 4 device 2 device 3 device 1

36 Buses What is a bus? Electrical channels that allow various devices inside the computer to communicate with each other Bus width determines the number of bits transmitted at one time Word size determines the number of bits the processor can interpret and execute at a given time

37 Expansion bus Allows the processor to communicate with peripheral devices Buses What are the two basic types of buses? System bus Part of the motherboard that connects the processor to main memory

38 Buses What are the types of expansion buses? Bus type determines type of expansion card you can add ISA (Industry Standard Architecture) Local bus VESA local bus PCI (Peripheral Component Interconnect) Accelerated Graphics Port (AGP) Universal serial bus (USB) PC Card bus fastest next fastest slowest processor memory AGP bus slot PCI bus expansion slots ISA bus expansion slots

39 Bays What is a bay? DVD-ROM drive CD-RW drive Zip drive empty drive bay floppy disk drive An open area inside the system unit used to install additional equipment Drive bays Used for disk drives External drive bay – –Also called exposed drive bay – –Accessible from outside the system unit Internal drive bay – –Also called hidden drive bay – –Concealed entirely within the system unit

40 Some peripheral devices have an AC adapter Power Supply What is a power supply? Converts alternating current (AC,115 to 120 volts) to direct current (DC, 5 to 12 volts)

41 What Is Input? What is input? Any data or instructions you enter into the memory of the computer Users can input data and instructions in a variety of ways

42 What Is Input? What are two types of input? Data A collection of raw unprocessed facts, figures, and symbols Instructions Programs Commands User responses DATA Bradley Kinkade 42 hours $12.50 per hour hard disk COMMANDS print the timecard PROGRAMS timecard USER RESPONSES Yes, the timecard entries are correct No, the timecard entries are not correct INSTRUCTIONS

43 What is Input? What are the three forms of instructions? Program A series of instructions that tells a computer how to perform the tasks necessary to process data into information User response An instruction you can issue by replying to a question that a computer program displays Command An instruction given to a computer program Users can issue commands by typing or pressing keys on the keyboard, clicking a mouse button, speaking into a microphone, or touching an area of a screen

44 What is Input? What are two features of most programs today? Menu-driven program Provides menus as a means of entering commands Menus contain a list of options from which you select Graphical user interface (GUI) Uses icons, buttons, and other graphical objects that allow you to select and issue commands icons menu buttons

45 What are Input Devices? What is an input device? Any hardware component that allows you to enter data, programs, commands, and user responses into a computer scanners and reading devices voice input keyboard pointing device video input digital camera

46 The Keyboard What is a keyboard? An input device that contains keys you press to enter data into the computer Typing area Letters of the alphabet, numbers, punctuation marks, and other basic keys Numeric keypad Calculator-style arrangement of keys numeric keypad typing area function keys Function keys Special keys programmed to issue commands to a computer

47 Toggle key Switches between two different states such as the NUM LOCK or CAPS LOCK keys Keys to position the insertion point Insertion point is a symbol that indicates where on the screen the next character you type will display The Keyboard What are some special types of keys? SHIFT, CTRL, ALT and others Used in combination with other keys to issue commands insertion point pointer

48 The Keyboard What is an ergonomic keyboard? Designed to minimize strain on your hands and wrists Ergonomics incorporates comfort, efficiency, and safety into the design of items in the workplace

49 Pointing Devices What is a pointing device? An input device that allows you to control a pointer on the screen A pointer is a small symbol on the screen The pointer takes several shapes I-beam pointing hand block arrow

50 Mouse What is a mouse? A pointing device that fits comfortably under the palm of your hand The most widely used pointing device on desktop computers The mouse controls the movement of the pointer, also called the mouse pointer, on the screen

51 A mouse pad provides better traction and protects the ball from a build up of dust and dirt A rubber or metal ball is on its underside When the ball rolls in a certain direction, electronic circuits in the mouse translate the movement of the mouse into signals the computer understands Mouse How does a mechanical mouse work? mouse pad ball wheel button mouse buttons

52 Mouse How does an optical mouse work? Uses devices that emit and sense light to detect the mouse s movement Some use optical sensors; others use laser More precise than a mechanical mouse and does not require cleaning Slightly more expensive back button wheel button forward button optical sensor

53 Point Click Right-click Double-click Drag Right-drag Rotate wheel Press wheel button Press and release the primary mouse button, which usually is the left mouse button Click Move the mouse across a flat surface until the pointer on the desktop rests on the item of choice Point Roll the wheel forward or backward Rotate wheel Quickly press and release the left mouse button twice without moving the mouse Double-click Point to an item, hold down the right mouse button, move the item to the desired location on the screen, and then release the right mouse button Right-drag Press the wheel button while moving the mouse on the desktop Press wheel button Point to an item, hold down the left mouse button, move the item to the desired location on the screen, and then release the left mouse button Drag Other Pointing Devices What are some common mouse operations? Press and release the secondary mouse button, which usually is the right mouse button Right-click

54 Other Pointing Devices? What is a trackball? A stationary pointing device with a ball on its top To move the pointer, you rotate the ball with your thumb, fingers, or the palm of your hand trackball

55 Other Pointing Devices What is a touchpad? Also called a trackpad A small flat, rectangular pointing device that is sensitive to pressure and motion Typically built onto keyboards of laptop or notebook computers touchpad

56 Other Pointing Devices What is a stylus? Used in professional graphical applications A graphics tablet, also called a digitizer or digitizing tablet, is a flat rectangular, electronic plastic board used with a stylus Looks like a ballpoint pen, but uses pressure to write text and draw lines Originally called a pen or electronic pen stylus or pen

57 Other Pointing Devices What is handwriting recognition software? Some notebooks and many handheld computers have touch screens that allow you to input data using a stylus Software translates handwritten letters and symbols into characters that the computer understands

58 Voice Input What is audio input? The process of entering any sound into the computer such as speech, music, and sound effects Requires a sound card Input sound via a device such as a microphone, tape player, CD player, or radio Windows stores audio files as waveforms Called WAV files with a.wav extension

59 Voice Input How does voice recognition work? You re right! Step 1: User dictates text into microphone. Step 2: An analog-to-digital converter (ADC) translates sound waves into digital measurements the computer can understand. Measurements include pitch, volume, silences, and phenomes. Phenomes are sound units such as aw and guh. Step 3: The software compares the spoken measurements to those in its database to find a match or list of possible matches. Step 4: To narrow a list down, the software presents the user with a list of choices or uses a natural language component to predict the most likely match. The user may correct any wrong selection made by the software. … Your write … You re right … Your right Natural Language Engine your, you re right, write Matches

60 Voice Input What is MIDI? An external device such as an electronic piano keyboard used to input music and other sound effects Music is stored in the computer

61 Digital Cameras What is a digital camera? Allows you to take pictures and store the photographed images digitally Images are viewable immediately on the camera You can download, or transfer a copy of the pictures from the camera to the computer Images can be edited, printed, or posted on a Web site or photo community

62 In digital images the pixel is a tiny square The greater the number of pixels, the better the quality of the image Digital Cameras What is resolution? The sharpness and clearness of an image The higher the resolution, the better the image quality, but the more expensive the camera A pixel ( pi cture el ement) is a single point in an electronic image

63 Video Input What is video input? The process of entering a full-motion recording into a computer and storing it on a storage medium Also called video capture A video capture card is an expansion card that converts the analog video signal into a digital signal that a computer can understand A digital video (DV) camera is a video camera that records video as digital signals analog video camera video-in plug digital video camera

64 video digitizer Used to capture an individual frame from an analog video and then save the picture in a file Video Input What are some factors related to video input? video decoder A card that decompresses video data Video files can require huge amounts of storage space Video compression is used to decrease the size of the files Files can be compressed using software or hardware

65 Scanners and Reading Devices What is a scanner? A device that captures data directly from source documents A source document is the original form of the data

66 A flatbed scanner, a more popular type, works similarly to a copy machine except it creates a file of the document in memory instead of a paper copy Scanners and Reading Devices What is an optical scanner? Usually called a scanner A light-sensing input device that reads printed text and graphics and then translates the results into a form the computer can use

67 OCR device Includes a small optical scanner for reading characters and sophisticated software for analyzing what is read Software Works with an optical scanner to convert a scanned image into a text file that can be edited Scanners and Reading Devices What is optical character recognition (OCR)? A technology that involves reading typewritten, computer-printed, or handwritten characters from ordinary documents and translating the images into a form that the computer can understand

68 Scanners and Reading Devices What is a bar code scanner? Uses laser beams to read bar codes

69 Input Devices for Physically Challenged Users Why are computers important for those with physical limitations? Americans with Disabilities Act (ADA) requires any company with 15 or more employees make reasonable attempts to accommodate the needs of physically challenged workers Many input devices address the needs of users with physical limitations

70 Input Devices for Physically Challenged Users What is a keyguard? A metal or plastic plate placed over the keyboard Allows users to rest their hands on the keyboard without accidentally pressing any keys Also guides a finger or pointing device so a user presses only one key at a time For users with limited hand mobility

71 Input Devices for Physically Challenged Users What is an on-screen keyboard? A graphic of a standard keyboard that displays on the user s screen A pointing device is used to press the keys

72 Input Devices for Physically Challenged Users What options are available for users with motor disabilities? A handheld switch can be used as a pointing device A portable computer or pointing device can be mounted to a wheelchair People with limited hand movement can use a head-mounted pointer

73 Implantation For paralyzed or speech impaired individuals A doctor will implant a computerized device containing a transmitter into the brain As the users thinks, the transmitter will send signals to the computer Gesture recognition Computer will be able to detect human motions Computers with this capabilities have the potential to recognize sign language, read lips, track facial movements, or follow eye gazes Input Devices for Physically Challenged Users What are new developments in computing that will benefit physically challenged users? Developments now in the prototype stage attempt to provide users with a natural computer interface

74 What is Output? What is output? Data that has been processed into a useful form, called information A computer generates several types of output Text Audio Video Graphics

75 What is Output? What is text? Consists of characters that create words, sentences, and paragraphs What is a graphic? Also called a graphical image A digital representation of non-text information such as a drawing, chart, and photograph

76 What is Output? What is audio? Music, speech, or any other sound What is video? Consists of full- motion images that are played back a various speeds Most video also has accompanying audio

77 What are Output Devices? What is an output device? Any hardware component that can convey information to a user printer monitor speakers

78 Display Devices What is a display device? Also called a display An output device that visually conveys text, graphics, and video information Information on a display device is sometimes called soft copy

79 Contains a cathode ray tube (CRT), a large sealed, glass screen The screen is coated with tiny dots of phosphor material A pixel, or picture element, is a single point in an electronic image Three dots (red, blue, and green) combine to make up each pixel Display Devices What is a CRT monitor? CRT monitor screen cathode ray tube

80 Display Devices What are typical sizes for CRT monitors? 15, 17, 19, 21, and 22 inches Monitor measured diagonally from one corner of the casing to the other The viewable size is the diagonal measurement of the actual viewing area provided by the monitor screen size viewable size

81 Display Devices What is a liquid crystal display (LCD) monitor? A type of flat-panel display Uses liquid crystals between two sheets of material to present information on a screen An electric current passes through the crystals which creates the images on the screen

82 Display Devices Where are some features of LCD screens? Lightweight and compact Consumes less than one-third of the power than does a CRT monitor Come in a variety of sizes Ideal for notebook and handheld computers

83 800 x 600 typically the standard Display Devices What is display resolution? Describes the sharpness and clearness of an image Resolution of a display device stated as dots, or pixels 1280 x 1024 maximum resolution of most monitors 800 horizontal pixels 600 vertical pixels Total of 480,000 pixels on screen 2048 x 1536 maximum for high-end monitors

84 Display Devices What is dot pitch? Another factor used to measure image clarity Sometimes called pixel pitch The distance between each pixel on a display The smaller the distance between the pixels, the sharper the image Use a monitor with a dot pitch of.29 millimeters or lower to minimize eye fatigue

85 Should be fast enough to maintain a constant, flicker-free image A high-quality monitor will provide a refresh rate of at least 75 hertz Display Devices What is refresh rate? Another factor in a monitor s quality Also called vertical frequency or vertical scan rate The speed that a monitor redraws images on the screen Measured according to hertz, which is the number of times per second the screen is redrawn The image on the screen redraws itself 75 times in a second

86 Display Devices What is a video card? Converts digital output from the computer into an analog video signal Sends the signal through a cable to the monitor Controls how the display device produces the picture Also called a graphics card or video adapter

87 Step 1 Step 2 Step 1 Step 2 Step 3 Step 1 Step 2 Step 4 Step 3 Step 1 Step 2 Step 3 Step 4 Step 5 Step 2 Step 3 Step 4 Step 5 Step 6 Step 1 Display Devices How does video travel from the processor to a CRT monitor? Step 1: The processor sends digital video data to the video card. Step 2: The video card s digital- to-analog converter (DAC) converts the digital video data to an analog signal. Step 3: The analog signal is sent through a cable to the CRT monitor. Step 4: The CRT monitor separates the analog signal into red, green, and blue signals. Step 5: Electron guns fire the three color signals to the front of the CRT. Step 6: An image displays on the screen when the electrons hit phosphor dots on the back of the screen.

88 Printers What is a printer? An output device that produces text and graphics on a physical medium such as paper or transparency film A hard copy, or printout, exists physically Two orientations portrait orientation landscape orientation

89 Printers What is an ink-jet printer? A type of nonimpact printer that forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper Usually uses individual sheets of paper stored in a removable or stationary tray The most popular type of color printer for use in the home

90 Printers What is the resolution of a printer? Also called sharpness and clarity Measured by the number of dots per inch (dpi) a printer can output 300 dpi1,200 dpi600 dpi

91 Printers What is a laser printer? A high-speed, high- quality nonimpact printer Usually use individual sheet of paper stored in a removable tray Can print text and graphics in very high quality resolution, ranging from 600 to 1,200 dpi Typically costs more than ink-jet printers, but are much faster

92 Printers How does a laser printer operate? Operates in a manner similar to a copy machine Creates images using a laser beam and powdered ink, called toner When toner runs out, you can replace the toner cartridge Toner cartridge prices range from $50 to $100 for about 5,000 printed pages

93 A page description language (PDL) tells the printer how to layout the contents of a printed page Laser printers use a PDL to process and store the entire page before they actually print it so they are sometimes called page printers Laser printers require a certain amount of memory in the device to store a page before printing Printers What is a page description language? PCL (Printer Control Language) Developed by Hewlett-Packard A standard printer language that supports the fonts and layout used in standard office documents PostScript Designed for complex documents with intense graphics and colors Used by professionals in the desktop publishing and graphic art fields

94 Printers What is a dye-sublimation printer? A type of thermal printer Also called a thermal dye transfer printer Uses heat to transfer colored dye to specially coated paper Cost several thousand dollars Can create images that are of photographic quality

95 Step 1: Insert media card into digital camera. Take the photograph with your digital camera. Step 2: Remove the media card from the digital camera and insert it into the card slot on the photo printer Step 3: Select desired image to print, number of copies, and size of print by pushing buttons on the photo printer. Step 4: Remove the photo from the photo printer Printers What is a photo printer? A color printer that can produce photo lab quality pictures as well as printing everyday documents Many photo printers can read media directly from a digital camera

96 Printers What is a large-format printer? Operates like an ink- jet printer, but on a much larger scale Creates photo- realistic quality color prints Used by graphic artists

97 Speakers and Headsets What is an audio output device? A component of a computer that produces music, speech, or other sounds, such as beeps Two commonly used audio output devices are speakers and headsets speakers

98 Speakers and Headsets What is Internet telephony? Voice output works with voice input Allows you to have a conversation over the Web, just as if you were on the telephone

99 Other Output Devices What is a data projector? A device that takes the image from a computer screen and projects it onto a larger screen so an audience of people can see the image clearly

100 Other Output Devices What is a fax modem? A modem that allows you to send (and sometimes receive) electronic documents as faxes Transmits computer – prepared documents, such as a word processing letter, or documents that have been digitized with a scanner, or digital camera external fax modem internal fax modem card in system unit

101 special- purpose terminals intelligent terminals Terminals What is a terminal? dumb terminals A device that performs both input and output because it consists of a monitor (output), a keyboard (input), and a video card Three basic categories

102 Terminals What is a dumb terminal? Has no processing power so it cannot function as an independent device Can enter and transmit data to, or receive and display information from, a computer to which it is connected Connect to a host computer that performs the processing and then sends the output back to the dumb terminal

103 Terminals What is an intelligent terminal? Has memory and a processor that has the capability of performing some functions independent of the host computer Sometimes called programmable terminals because they can be programmed by the software developer to perform basic tasks

104 Terminals What is a point-of-sale (POS) terminal? Records purchases at the point where the consumer purchases a product or a service Output from POS terminals serve as input to other computers to maintain sales records, update inventory, verify credit, and perform other activities associated with the sales transactions that are critical to running the business POS terminal

105 Output Devices for Physically Challenged Users What other output options are available for visually impaired users? Change Window s settings such as increasing the size or changing the color of the text to make the words easier to read Blind users can work with voice output where the computer reads the information that displays on the screen A Braille printer outputs information in Braille onto paper

106 Memory Versus Storage What is storage? The media on which data, instructions, and information are kept, as well as the devices that record and retrieve these items

107 Memory Versus Storage How does storage differ from memory? When you want to work with a file, you remove it from storage and place it in memory When you are finished with the file, you remove it from memory and return it to storage Storage also called secondary storage, auxiliary storage, permanent storage, or mass storage Storage holds items such as data, instructions, and information for future use Storage is nonvolatile

108 Memory Versus Storage What is a storage medium and a storage device? storage medium The physical material on which a computer keeps data, instructions, and information storage device The computer hardware that records and retrieves items to and from a storage medium

109 Writing Process of transferring items from memory to a storage medium Serves as a source of output Memory Versus Storage What is reading and writing? Reading Process of transferring data, instructions, and information from a storage medium into memory Serves as a source of input

110 Memory Versus Storage What is access time? The amount of time it takes the device to locate an item on a disk Defines the speed of a disk storage device Memory (RAM) Compact Disc Floppy Disk Tape Hard Disk cost less expensive more expensive speed faster slower

111 Memory Versus Storage What is capacity? The number of bytes (characters) a storage medium can hold Manufacturers use many terms to define the capacity of storage media Storage Term Abbreviation Number of bytes Kilobyte Megabyte Gigabyte Terabyte Petabyte KB MB TB GB PB 1 thousand 1 million 1 billion 1 trillion 1 quadrillion

112 Floppy Disks What is a floppy disk? A portable, inexpensive storage medium Consists of a thin, circular, flexible plastic disk with a magnetic coating Enclosed in a square-shaped plastic shell Today s standard disk is 3.5 wide

113 Floppy Disks What are the parts of a floppy disk? A thin circular flexible film is enclosed between two liners A piece of metal called a shutter covers an opening to the recording surface shell shutter liner magnetic coating flexible thin film metal hub

114 Floppy Disks A device that can read from and write on a floppy disk Most personal computers have a floppy disk drive, in which you insert and remove a floppy disk What is a floppy disk drive (FDD)? floppy disk floppy disk drive

115 Floppy Disks How are floppy disk drives designated ? Two floppy drives drive A drive B One floppy drive drive A

116 Floppy Disks How does a floppy disk store data? A type of magnetic media Uses magnetic patterns to store items such as data, instructions, and information on a disk s surface Able to access (read) data from and place (write) data on a magnetic disk any number of times The read/write head in the floppy disk drive is the mechanism that actually reads items from or writes items on the floppy disk

117 Floppy Disks What is a write-protect notch? A small opening with a cover that you slide up or down Protects floppy disks from accidentally being erased notch closed means you can write on the disk notch open means you cannot write on the disk write-protected not write-protected

118 Step 6: The read/write heads read data from and write data on the floppy disk. Step 6 Step 5: A motor positions the read/write heads over the correct location on the recording surface of the disk. Step 5 Step 4: A motor causes the floppy disk to spin. Step 4 Step 3: If disk access is a write instruction, the circuit board verifies whether the disk can be written to or not. Step 3 Step 2: When you initiate a disk access, the circuit board on the drive sends signals to control movement of the read/write heads and the disk. Step 2 Step 1: When you insert the floppy disk into the drive, the shutter moves to the side to expose the recording surface on the disk. Step 1 Floppy Disks How does a floppy disk drive work?

119 Floppy Disks What are tracks and sectors? Track: a narrow recording band that forms a full circle on the surface of the disk Pie shaped sections break the tracks into small arcs called sectors A sector can store up to 512 bytes of data A typical floppy disk stores data on both sides of the disk sector 18 per track track 80 per side 80 tracks per side X 18 sectors per track X 2 sides per disk X 512 bytes per sector = 1,474,560 bytes

120 Floppy Disks What is a cluster? The smallest unit of disk space that stores data Also called an allocation unit 2 to 8 sectors depending on the operating system Each cluster holds data from only one file One file can span many clusters cluster 2 to 8 sectors

121 Floppy Disks What is formatting? The process of preparing a disk for reading and writing Formatting marks bad sectors as unusable

122 HiFD (High-Capacity Floppy Disk) drive Uses a 200 MB HiFD disk Developed by Sony Electronics, Inc. High-Capacity Disks What is a high-capacity disk drive? A disk drive that uses disks with capacities of 100 MB and greater SuperDisk drive Uses a 120 MB or a 250 MB SuperDisk Developed by Imation Zip ® drive Uses a Zip ® disk that can store 100 MB or 250 MB of data Developed by Iomega Corporation built in Zip ® drive

123 Hard Disks What a hard disk? Consists of several inflexible, circular platters that store items electronically Also called a hard disk drive or a fixed disk A platter is coated with a material that allows items to be recorded magnetically on its surface The components of a hard disk are enclosed in an airtight, sealed case to protect them Hard disk installed in system unit

124 Step 4: The head actuator positions the read/write head arms over the correct location on the platters to read or write data Step 4 Step 2: A small motor spins the platters while the computer is running Step 2 Step 3: When software requests a disk access, the read/write heads determine the current or new location of the data Step 3 Step 1: The circuit board controls the movement of the head activator and a small motor Step 1 Hard Disks How does a hard disk work?

125 Hard Disks What is a cylinder? The location of a single track through all platters A single movement of the read/write head arms can read all the platters of data track cylinder

126 Hard Disks How does access time compare for a hard disk and a floppy disk? A hard disk s access time is significantly faster than a floppy disk The hard disk spins much faster than a floppy disk A hard disk spins constantly, while a floppy disk starts spinning only when it receives a read or write command Hard disk Approximately 5 to 11 milliseconds Floppy disk 84 milliseconds or approximately ½ a second

127 Hard Disks What is a partition? You can divide a formatted hard disk into separate areas called partitions Done by issuing a special operating system command Each partition functions as if it were a separate hard disk drive instructions, and information to improve data reliability drive C Designation for first partition or for a single partition on the hard disk drive D Designation for second partition on the hard disk

128 Hard Disks Windows provides many maintenance and monitoring utilities for a hard disk on the System Tools submenu What utilities maintain a hard disk drive?

129 Compact Discs What is a compact disc (CD)? A flat, round, portable, metal storage medium that usually is 4.75 inches in diameter and less than one-twentieth of an inch thick Most personal computers today include some type of compact disc drive Also called an optical disc Available in a variety of formats CD-ROM CD-R CD-RW DVD-ROM

130 Step 3: Reflected light is deflected to a light-sensing diode, which sends digital signals of 1 to the computer. Absence of reflected light is read as a digital signal of 0. Step 1: A laser diode shines a light beam toward the compact disc. Step 2: If light strikes a pit, it scatters. If light strikes land, it is reflected back toward the laser diode. Compact disc label lens prism laser diode Step 1 Compact disc label lens prism laser diode Items are stored using microscopic pits (indentations) and land (flat areas) that are in the middle layer of the disk A laser light reads items from the compact disc Compact Discs How does a laser read data on a compact disc? Step 2 Compact disc label lens prism laser diode pit land Step 3 Compact disc label lens prism laser diode Light- sensing diode 0 1 pit land

131 CD-ROMs What is the storage capacity of a CD-ROM? A typical CD-ROM holds about 650 MB of data, instructions, and information Manufactures use CD-ROMs to store and distribute today s multimedia and other complex software

132 40X 40 X 150 KB per second = 6,000 KB per second or 6 MB per second CD-ROMs What is the data transfer rate of a CD-ROM drive? The time it takes a drive to transmit data, instructions, and information from the drive to another device Slower CD-ROM drives produce choppy images or sound Drive speed measured relative to original CD-ROM drives (150 KB per second) 75X 75 X 150 KB per second = 12,250 KB per second or MB per second range of current rates

133 CD-R and CD-RW What is a CD-R (compact disc-recordable)? A multisession compact disc onto which you can record your own items such as text, graphics, and audio You write on the CD-R using a CD recorder or a CD-R drive and special software The CD-R drive can read and write both audio CDs and standard CD-ROMs You cannot erase the disc s contents Most CD-ROM drives can read a CD-R

134 CD-R and CD-RW What is a CD-RW (compact disc-rewritable)? An erasable disc you can write on multiple times You must have CD-RW software and a CD-RW drive Discs can be read only by multiread CD-ROM drives Drives that can read audio CDs, data CDs, CD-Rs, and CD-RWs Most recent CD-ROM drives are multiread

135 DVD-ROMs What is a DVD-ROM (digital video disc-ROM)? An extremely high capacity compact disc capable of storing from 4.7 GB to 17 GB You must have a DVD-ROM drive or DVD player to read a DVD-ROM Looks just like a CD-ROM but data, instructions, and information is stored in a slightly different manner to achieve a higher storage capacity

136 DVD-ROMs What are other various DVD formats? Digital motion picture DVD Used to play a movie on your television set or view on the computer DVD-R (DVD-recordable) A recordable DVD that you can write on once and read from many times DVD+RW A competing technology to DVD-RAM DVD-RAM A rewritable DVD that allows you to erase and record on the disc multiple times

137 Tapes What is tape? A magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost A tape drive reads from and writes data and information on a tape Older computers used reel-to-reel tape drives A tape cartridge is a small, rectangular, plastic housing for tape used in today s tape drives

138 Tapes Where is tape used? Used by business and home users to backup personal computer hard disks Both external and internal tape units for personal computers Larger computers use tape cartridges mounted in a separate cabinet called a tape library Three common types of tape drives

139 Miniature Mobile Storage Media What is miniature mobile storage media? Handheld devices use miniature mobile storage media to augment internal storage Storage CapacityDevice NameType, Use Clik! Disk CompactFlash Microdrive SmartMedia 40 MB 2 to 256 MB 1 GB 2 to 128 MB Cartridge Digital cameras, notebook computers Memory Card Digital cameras, handheld computers, notebook computers, printers, cellular telephones Memory card Digital cameras, handheld computers, music players, video cameras Memory Card Digital cameras, handheld computers, photo printers, cellular telephones

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