CHAPTER 4 Hardware applications for Education.

CHAPTER 4 Hardware applications for Education

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

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

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

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 Athlon™ Pentium® 4 Celeron™ Duron™

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

What is the control unit? A component of the CPU that directs and coordinates most of the operations in the computer CPU Arithmetic/ Logic Unit (ALU) The control unit repeats a set of four basic operations: Control Unit Control Unit 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

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

What is a machine cycle? Together the four operations of the CPU comprise a machine cycle 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 4: The results of the math problem are stored in memory The result in memory displays on the screen of the monitor Step 3: The ALU executes the math problem

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

How do computers represent data?
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

What is the binary system?
Data Representation What is the binary system? 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 Binary Digit (bit) Electronic Charge Electronic State

Data Representation What is a byte?
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 8-bit byte for the number 3 8-bit byte for the number 5 8-bit byte for the capital letter T

What are two popular coding systems to represent data?
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

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 MHz - one million ticks of the system clock GHz – one billion ticks of the system clock Clock speed (clock rate) measured in megahertz (MHz) and gigahertz (GHz)

Data Representation How is a character sent from the keyboard to the computer? Step 4: After processing, the binary code for the letter T is converted to an image on the output device 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 1: The user presses the letter T key on the keyboard

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

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

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

What is random access memory (RAM)?
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 As additional programs and data are requested, they also load from storage into RAM Most RAM is volatile

Memory How are applications transferred in and out of RAM?
Step 1: When your computer is running, certain operating system files are in RAM. Shown here is the operating system’s user interface. Storage (hard disk) RAM 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 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 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. 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 What is a memory module?
Small circuit board with RAM chips, which are smaller in size than processor chips Inserts into the motherboard Three types: SIMMS, DIMMS, and RIMMS single inline memory modules (SIMMs) Rambus® inline memory module (RIMM) dual inline memory modules (DIMMs)

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

What is read-only memory (ROM)?
Memory chips that contain data, instructions, or information that is recorded permanently 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 Data can only be read, cannot be modified

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

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

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

What is a PC card? 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)

Ports mouse What is a port? keyboard 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 USB USB serial port printer (parallel port) speaker monitor microphone game port network telephone line out telephone line in FM reception svideo out cable TV

Ports What are the different types of connectors?

Ports What is a serial port? Transmits one bit of data at a time
byte representation for number 1 ( ) serial transmission of data What is a serial port? byte representation for number 3 ( ) 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 byte representation for number 5 ( ) DB-9 female connector DB-9 male connector

Ports What is a parallel port?
byte representation for number 1 What is a parallel port? byte representation for number 3 byte representation for number 5 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 is a standard that specifies how older and newer peripheral devices transfer data to and from a computer DB-25 male connector DB-25 female connector

What is a universal serial bus port (USB)?
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

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

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

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

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 processor fastest next fastest slowest memory AGP bus slot PCI bus expansion slots ISA bus expansion slots

Bays DVD-ROM drive What is a bay? 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 CD-RW drive Zip drive empty drive bay floppy disk drive

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

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

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

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

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

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 voice input video input keyboard scanners and reading devices pointing device digital camera

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 function keys typing area Function keys Special keys programmed to issue commands to a computer numeric keypad

The Keyboard What are some special types of keys?
SHIFT, CTRL, ALT and others Used in combination with other keys to issue commands 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 insertion point pointer

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

Pointing Devices What is a pointing device?
I-beam 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 block arrow pointing hand

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

Mouse How does a mechanical mouse work?
mouse pad How does a mechanical mouse work? 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 buttons wheel button ball A mouse pad provides better traction and protects the ball from a build up of dust and dirt

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 wheel button back button forward button optical sensor

Other Pointing Devices
What are some common mouse operations? Move the mouse across a flat surface until the pointer on the desktop rests on the item of choice Point 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 Press and release the secondary mouse button, which usually is the right mouse button Right-click 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 Roll the wheel forward or backward Rotate wheel 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 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

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

What is 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 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

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

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

Natural Language Engine
Voice Input How does voice recognition work? You’re right! 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. 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 1: User dictates text into microphone. …Your write …You’re right …Your right Natural Language Engine your, you’re right, write Matches

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

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 Ima

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 (picture element) is a single point in an electronic image In digital images the pixel is a tiny square The greater the number of pixels, the better the quality of the image

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 digital video camera video-in plug 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

A card that decompresses video data
Video Input What are some factors related to video input? 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 video decoder A card that decompresses video data video digitizer Used to capture an individual frame from an analog video and then save the picture in a file

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

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 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

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 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

What is a bar code scanner? Uses laser beams to read bar codes

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

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

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

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

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 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 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

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 Graphics Video Audio

What is Output? What is text? What is a graphic?
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

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

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

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

Display Devices What is a CRT monitor?
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 cathode ray tube screen CRT monitor

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

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

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

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

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

Display Devices What is refresh rate?
Should be fast enough to maintain a constant, flicker-free image 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 A high-quality monitor will provide a refresh rate of at least 75 hertz The image on the screen redraws itself 75 times in a second

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

Display Devices Step 1 Step 2 Step 3 Step 4 Step 5 Step 1 Step 2 Step 1 Step 2 Step 4 Step 3 Step 1 Step 2 Step 3 Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 1 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.

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

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

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 dpi 600 dpi 1,200 dpi

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

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

Printers What is a page description language?
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 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

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

Printers What is a photo printer?
Step 1: Insert media card into digital camera. Take the photograph with your digital camera. Step 4: Remove the photo from 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 2: Remove the media card from the digital camera and insert it into the card slot on the 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

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

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

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

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

internal fax modem card in system unit
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

intelligent terminals special-purpose terminals
What is a terminal? 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 dumb terminals intelligent terminals special-purpose terminals

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

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

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

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

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

Memory Versus Storage How does storage differ from memory?
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 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

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

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 Writing Process of transferring items from memory to a storage medium Serves as a source of output

Memory Versus Storage What is access time?
cost less expensive more expensive speed faster slower 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) Hard Disk Compact Disc Floppy Disk Tape

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

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

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 liner shutter metal hub magnetic coating flexible thin film shell

Floppy Disks What is a floppy disk drive (FDD)?
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 floppy disk floppy disk drive

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

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

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 open means you cannot write on the disk write-protected not write-protected notch closed means you can write on the disk

Floppy Disks How does a floppy disk drive work?
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 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 3: If disk access is a write instruction, the circuit board verifies whether the disk can be written to or not. Step 3 Step 6: The read/write heads read data from and write data on the floppy disk. Step 6 Step 4: A motor causes the floppy disk to spin. Step 4 Step 5: A motor positions the read/write heads over the correct location on the recording surface of the disk. Step 5

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

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

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

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 HiFD™ (High-Capacity Floppy Disk) drive Uses a 200 MB HiFD™ disk Developed by Sony Electronics, Inc. Zip® drive Uses a Zip® disk that can store 100 MB or 250 MB of data Developed by Iomega Corporation built in Zip® drive

Hard disk installed in system unit
Hard Disks 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 What a hard disk? Hard disk installed in system unit

Hard Disks How does a hard disk work?
Step 1: The circuit board controls the movement of the head activator and a small motor Step 1 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 4: The head actuator positions the read/write head arms over the correct location on the platters to read or write data Step 4

Hard Disks What is a cylinder?
track 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

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

Designation for second partition on the hard disk
Hard Disks drive C Designation for first partition or for a single partition on the hard disk 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 D Designation for second partition on the hard disk

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

CD-ROM CD-RW CD-R DVD-ROM
Compact Discs What is a compact disc (CD)? CD-ROM 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-RW CD-R DVD-ROM

Compact Discs How does a laser read data on a compact disc?
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 Step 2 Compact disc label lens prism laser diode pit land Step 3 Compact disc label lens prism laser diode Light-sensing diode 1 pit land Step 1 Compact disc label lens prism laser diode Compact disc label lens prism laser diode Compact disc label 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. 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.

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

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) 40X 40 X 150 KB per second = 6,000 KB per second or 6 MB per second range of current rates 75X 75 X 150 KB per second = 12,250 KB per second or MB per second

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

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

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

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-RAM A rewritable DVD that allows you to erase and record on the disc multiple times 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

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

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

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

CHAPTER 4 Hardware applications for Education.

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CHAPTER 4 Hardware applications for Education.

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