Lecture 7 Hardware applications for Education Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
The System Unit What are common components inside the system unit? ° ° Processor Memory module Expansion cards • Sound card • Modem card • Video card • Network interface card Ports and Connectors Lectured by Prof. Jese Role @ UEAB 2008
The System Unit What is the motherboard? Also called the system board ° Main circuit board in the system unit ° Contains many electronic components ° Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Central Processing Unit 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 Pentium® 4 Athlon™ Celeronby Prof. Jese Role @ ™ Duron™ Lectured UEAB 2008
Central Processing Unit What are the components of the central processing unit (CPU )? CPU Control Unit Arithmetic/ Logic Unit (ALU) Lectured by Prof. Jese Role @ UEAB 2008
Central Processing Unit What is the control unit? ° A component of the CPU that directs and coordinates most of the operations in the computer CPU The control unit repeats a set of four basic operations: ° Fetch Arithmetic/ Control Unit – obtain a program instruction or data item from Control Unit Logic Unit memory (ALU) ° ° ° Decode - translate the instruction into commands Execute - carry out the command Store by write the @ Lectured - Prof. Jese Role result to memory UEAB 2008
Central Processing Unit 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 • Execution time (e-time) – time it takes to execute and store e-time i-time Lectured by Prof. Jese Role @ UEAB 2008
Central Processing Unit What is a machine cycle? ° Together the four operations of the CPU comprise a machine cycle A student enters a math problem into Step 1: The control the memory of the unit fetches the computer Step 2: The control math problem from unit decodes the Step 4: Step 3: The memory. The. ALU results of the math problem and executes the math sends problem ALU math it problem to the are stored in memory The result in memory displays on the screen of the monitor Lectured by Prof. Jese Role @ UEAB 2008
Central Processing Unit 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 . nd. a CPU Control Unit . or. Arithmetic/ Logic Unit (ALU) Lectured by Prof. Jese Role @ UEAB 2008 . not.
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 1 1 0 1 0 Lectured by Prof. Jese Role @ UEAB 2008 0
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 Lectured by Prof. Jese Role @ UEAB 2008
Data Representation What is a byte? ° ° Eight bits are grouped together to form a byte 0 s and 1 s 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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ (GHz) UEAB 2008 MHz - one million ticks of the system clock GHz – one billion ticks of the system clock
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 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 (01010100) 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 Lectured by Prof. Jese Role @ UEAB 2008
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 ° Three basic items stored in memory application programs that carry out a specific task data being processed by application programs Lectured by Prof. Jese Role @ UEAB 2008
Memory How is memory measured? ° Size of memory is measured by the number of bytes available • Kilobyte - 1, 024 bytes • Megabyte - one million bytes Lectured by Prof. Jese Role @ UEAB 2008
Memory What are the two types of memory in the system unit? volatile memory Volatile Memory Loses its contents when the computer's power off computer's power is turned off nonvolatile memory Does not lose its contents when the computer’s power is turned off Lectured by Prof. Jese Role @ UEAB 2008
Memory 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 Lectured by Prof. Jese Role @ UEAB 2008
Memory How are applications transferred in and out of RAM? Step 1: When your computer is Step 2: When you running, certain start a word operating system Step 3: When you processing program files Word, RAM may in RAM. quit are When you Step 5: such 4: Word, the as Shown here is the be used to store may quit a spreadsheet start. Excel, RAM program loads into operating system’s another program or RAM from a hard be used such as programto store user interface. data. As program oris disk. The program another you create Excel, the program removed from the a document, it is in data. into RAM loads. Excel is from screen disk. theyour removed displays a hard and As RAM and from you operating system’s screen spreadsheet, create a screen. on yourand the userin RAM and operating system’s it is interface redisplays. your user interface displays on redisplays. screen. Storage (hard disk) RAM Lectured by Prof. Jese Role @ UEAB 2008
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) dual inline memory modules (DIMMs) Rambus® inline memory module (RIMM) Lectured by Prof. Jese Role @ UEAB 2008
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) Lectured by Prof. Jese Role @ UEAB 2008
Memory What is read-only memory (ROM)? ° Memory chips that contain data, instructions, or information that is recorded permanently Data can only be read, cannot be modified Nonvolatile — Contents not lost when the computer is turned off 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 Lectured by Prof. Jese Role @ UEAB 2008
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 board, @ Lectured by Prof. Jese Role board, adapter UEAB 2008 card, adapter, interface card, add-in, and add-on
Expansion Slots and Expansion Cards Video card also called video adapter or graphics card What are four common types of expansion cards? Sound card Network interface card (NIC) also called a network card Lectured by Prof. Jese Role @ UEAB 2008 Modem card also called an internal modem
Expansion Slots and Expansion Cards What is Plug and Play? The computer automatically can configure cards and other devices as you install them Lectured by Prof. Jese Role @ UEAB 2008
Expansion Slots and Expansion Cards 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) ° Lectured by Prof. Jese Role @ UEAB 2008
Ports What is a port? 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 ° keyboard mouse USB serial port printer (parallel port) speaker monitor microphone game port network telephone line in svideo out Lectured by Prof. Jese Role @ UEAB 2008 telephone line out FM reception cable TV
Ports What are the different types of connectors? Lectured by Prof. Jese Role @ UEAB 2008
Ports What is a serial port? serial transmission of data byte representation for number 3 (0011) Transmits one bit of data at a time ° Used to connect devices that do not require fast transmission rates • mouse • keyboard • modem DB-9 female ° Two common types connector • 25 -pin • 9 -pin ° DB-9 male Lectured by Prof. Jese Role @ connector UEAB 2008 byte representation for number 1 (00110001) byte representation for number 5 (00110101)
Ports What is a parallel port? ° ° ° Connects devices that can transfer more than one bit at a time Usually used for printers Two newer types byte representation for number 1 byte representation for number 3 byte representation for number 5 • EPP (Enhanced Parallel Port) • ECP (Extended Capabilities Port) ° IEEE 1284 is a standard that specifies how older DB-25 male and newer peripheral connector devices transfer data to and from a computer DB-25 Lectured by Prof. Jese Role @ female UEAB 2008
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 ° Lectured by Prof. Jese Role @ UEAB 2008
Ports How are multiple USB devices connected? ° Daisy Chain ° USB hub • Devices connected together • Plugs into the USB port on the outside the system unit in a chain computer • Contains multiple USB ports Computer with USB port USB hub device 1 device 3 device 2 device 1 device 4 Lectured by Prof. Jese Role @ 2 UEAB 2008 device 3 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 Lectured by Prof. Jese Role @ UEAB 2008
Buses What are the two basic types of buses? System bus Part of the motherboard that connects the processor to main memory Expansion bus Allows the processor to communicate with peripheral devices Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ bus expansion slots ISA UEAB 2008
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 CD-RW drive Zip drive empty drive bay – Also called exposed drive bay – Accessible from outside the system unit floppy disk drive • Internal drive bay – Also called hidden drive bay – Concealed entirely within the system unit Lectured by Prof. Jese Role @ UEAB 2008
Power Supply What is a power supply? Converts alternating current (AC, 115 to 120 volts) to direct current (DC, 5 to 12 volts) Some peripheral devices have an AC adapter Lectured by Prof. Jese Role @ UEAB 2008
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 ° Lectured by Prof. Jese Role @ UEAB 2008
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 t ct re rrec r co co t re S es a re no SE ntri s a N e e PO ard ntri ES ec rd e R R e tim eca E d US s, th e tim DS car S Ye , th ANtime M M No M the RA CO int OG ard pr PR ec tim hard disk INSTRUCTIONSProf. Jese Role @ Lectured by UEAB 2008
What is Input? What are 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 Lectured by Prof. Jese Role @ area of a screen UEAB 2008
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 icons buttons Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 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 function keys ° Numeric keypad • Calculator-style arrangement of keys ° Function keys • Special keys programmed to issue commands to typing area a computer numeric keypad ° Lectured by Prof. Jese Role @ UEAB 2008
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 ° pointer insertion point Lectured by Prof. Jese Role @ UEAB 2008
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 ° Lectured by Prof. Jese Role @ UEAB 2008
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 block arrow Lectured by Prof. Jese Role @ pointing UEAB 2008 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 Lectured by Prof. Jese Role @ UEAB 2008
Mouse 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 A mouse pad provides better traction and protects the ball from a build up of dust and dirt mouse buttons Lectured by Prof. Jese Role @ UEAB 2008 wheel button ball
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 Lectured by Prof. Jese Role @ UEAB 2008
Other Pointing Devices What are some common mouse operations? ° Point ° Click ° Right-click ° Double-click ° Drag ° Right-drag ° Rotate wheel ° Press wheel button Press to press Point the wheel Quickly anrelease Roll the wheel Move the mouse and item, button whilethe down holdrelease andsecondary forward flat across the release aor the movingbutton, mouse right mouse left mouse backward surface until the primary the mouse on the usuallythethe which move button which pointertwice is button, desktop on the right mouse item to to button the item rests without moving desktopis the left usually theon desired of choice the itemlocation mouse button mouse on the screen , screen, and then release the right mouse left mouse button Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 trackball
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 touchpad computers ° Lectured by Prof. Jese Role @ UEAB 2008
Other Pointing Devices What is a stylus? ° ° Looks like a ballpoint pen, but uses pressure to write text and draw lines stylus or pen Originally called a pen or electronic 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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Voice Input How does voice recognition work? You’re right! Natural Language Engine …Your write …You’re right …Your right Step 1: User dictates 2: An analog-to-digital Step 3: narrow a list down, Step 4: To The software converter (ADC) translates text compares the spoken user the into microphone. the software presents sound waves into digital with a list of choices or uses a measurements to those measurements the computer natural language component to in its database to find a can understand. Measurements predict the most of possible match or list likely match. include pitch, volume, silences, Thematches. correct any wrong user may and phenomes. Phenomes are selection made by the software. sound units such as aw and guh. Matches your, you’re Lectured by Prof. Jese Role @ UEAB 2008 right, write
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Video Input What is video input? ° ° The process of entering a full-motion recording into a computer and storing it on a storage medium digital video Also called video capture video-in ° A video capture card is an plug ° 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 Lectured by Prof. Jese Role @ camera UEAB 2008 camera
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 digitizer video decoder Used to capture an individual A card that frame from an decompresses analog video and video data then save the Lectured by Prof. picture @ a file Jese Role in UEAB 2008
What is a scanner? Scanners and Reading Devices A device that captures data directly from source documents ° A source document is the original form of the data ° Lectured by Prof. Jese Role @ UEAB 2008
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 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 Lectured by Prof. Jese Role @ UEAB 2008
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 OCR device Software Works with an optical scanner to convert a scanned image into a text file that can be edited Includes a small optical scanner for reading characters and sophisticated software for analyzing what is read Lectured by Prof. Jese Role @ UEAB 2008
Scanners and Reading Devices What is a bar code scanner? ° Uses laser beams to read bar codes Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ limitations UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Implantation Gesture recognition • Computer will be able to detect human motions • For paralyzed or speech impaired individuals • A doctor will implant a • Computers with this capabilities have the potential to recognize sign language, read lips, track facial movements, or follow eye gazes computerized device containing a transmitter into the brain • As the users thinks, the transmitter will send Lectured by Prof. signals@ the computer Jese Role to UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
What is Output? What is audio? ° Music, speech, or any other sound Consists of fullmotion images that are played back a various speeds ° Most video also has accompanying Lectured by Prof. Jese Role @ UEAB 2008 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 Lectured by Prof. Jese Role @ UEAB 2008
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 ° Lectured by Prof. Jese Role @ UEAB 2008
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 CRT monitor Lectured by Prof. Jese Role @ UEAB 2008 screen
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 en e ize s r sc bl a e w e vi Lectured by Prof. Jese Role @ UEAB 2008 ize s
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 1280 x 1024 maximum resolution of most monitors 2048 x 1536 maximum for high-end monitors 800 horizontal pixels 600 vertical pixels Total of 480, 000 pixels on screen Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 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 The image on the screen redraws itself 75 times in a second Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Display Devices Step 1 How does video travel from the processor to a CRT monitor? Step 1: The processor sends digital video data to the video Step 2: The video card’s digitalcard. to-analog converter (DAC) Step 3: The analog signal is converts the digital video data sent through signal. to the CRT to an analog a cable monitor. Step 4: The CRT monitor separates the analog signal into red, green, and blue signals. Step 5: Electron guns fire three 6: An image displays on Step color signals to the front of the CRT. when the electrons the screen hit phosphor dots on the back of the screen. Step 2 Step 3 Step 4 Step 5 Step 6 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 1, 200 dpi
Printers What is a laser printer? ° ° A high-speed, highquality 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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Post. Script Designed for complex documents with intense graphics and colors Used by professionals in the desktop publishing and graphic Lectured by Prof. Jese Role @fields art UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Step 1: Insert media 4: 3: Select desired 2: Remove the photo to print, camera. image card from the media from the photo card into digitalnumber printer of copies, and size digital camera and of Take the photograph print by pushing insert it into the with your digital card buttons slot on the photo camera. on photo printer Lectured by Prof. Jese Role @ UEAB 2008
Printers What is a large-format printer? ° ° ° Operates like an inkjet printer, but on a much larger scale Creates photorealistic quality color prints Used by graphic artists Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 ° Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 internal fax modem card in system unit
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 Lectured by Prof. Jese Role @ UEAB 2008 specialpurpose 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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008 POS terminal
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 Lectured by Prof. Jese Role @ onto paper UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Memory Versus Storage What is a storage medium and a storage device? storage device The computer hardware that records and retrieves items to and from a storage medium The physical material on which a computer keeps data, instructions, and information Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Memory Versus Storage siv en xp mo re e ter Memory (RAM) fas Hard Disk cost speed Tape Lectured by Prof. Jese Role @ UEAB 2008 en xp r Floppy Disk we slo siv e Compact Disc se ° The amount of time it takes the device to locate an item on a disk Defines the speed of a disk storage device les ° e What is access time?
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 KB 1 thousand Megabyte MB 1 million Gigabyte GB 1 billion Terabyte TB 1 trillion Petabyte PB 1 quadrillion Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 shell Lectured by Prof. Jesemagnetic Role @ UEAB 2008 coating flexible thin film
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 drive Lectured by Prof. Jese Role @ UEAB 2008
Floppy Disks How are floppy disk drives designated? One floppy drive A Two floppy drives drive A drive B Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 notch closed means you can write on the disk write-protected not write-protected Lectured by Prof. Jese Role @ UEAB 2008
Floppy Disks How does a floppy disk drive work? Step 1: When you insert the floppy disk into the drive, the shutter moves Step 2: When you Step 1 to the side to expose initiate a disk the recording surface Step 3: If disk access Step 6 access, the circuit on a write instruction, the disk. is board on the drive Step 4: A motor the circuit board sends signals to causes A motor Step 5: the floppy verifies whether the control spin. disk to movement positions be written to the disk read/write of thecan read/write heads or not. heads and the disk. over the correct Step 6: The location on the read/write heads Step 5 recording from and surface read data of the disk. write data on the Step 4 floppy disk. Step 2 Step 3 Lectured by Prof. Jese Role @ UEAB 2008
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 80 per side Lectured by Prof. Jese Role @ 80 tracks per side X 18 sectors per track X 2 sides per disk X UEAB 2008 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 Lectured by Prof. Jese Role @ UEAB 2008
Floppy Disks What is formatting? ° ° The process of preparing a disk for reading and writing Formatting marks bad sectors as unusable Lectured by Prof. Jese Role @ UEAB 2008
High-Capacity Disks What is a high-capacity disk drive? ° A disk drive that uses disks with capacities of 100 MB and greater Hi. FD™ (High-Capacity Floppy Disk) drive Uses a 200 MB Hi. FD™ disk Developed by Sony Electronics, Inc. Super. Disk™ drive Uses a 120 MB or a 250 MB Super. Disk™ Developed by Imation Zip® drive Uses a Zip® disk that can store 100 MB or 250 MB of data Developed Prof. Iomega @ Lectured by by Jese Role Corporation UEAB 2008 built in Zip® drive
Hard Disks What a hard disk? ° ° Hard disk installed in system unit 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 Lectured by Prof. Jese Role @ UEAB 2008
Hard Disks How does a hard disk work? Step 1: The circuit board controls the movement of the Step activator head 2: A smalland motor spins the a small motor platters while the Step 3: When computer is software requests running a disk access, the Step 4: The head read/write heads actuator positions determine the head the read/write current or new arms over the location on correct of the data the platters to read or write data Step 2 Step 1 Step 3 Step 4 Lectured by Prof. Jese Role @ UEAB 2008
Hard Disks cylinder 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 Lectured by Prof. Jese Role @ UEAB 2008 track
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Compact Discs What is a compact disc (CD)? ° ° M O -R D A flat, round, portable, C CD metal storage medium -RW 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 OM Available in a D-R Lectured by Prof. Jese Role @ DV UEAB 2008 variety of formats CD-R
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 Compact disc label 1 Step 2 3 pit lens Step 3: Reflected lightais 2: If laser diode 1: A light strikes pit, it scatters. If light strikes shines a to a light-sensing deflectedlight beam toward land, it is reflected the compact sends digital diode, which disc. back toward of to the computer. signals the 1 laser diode. Absence of reflected light is read as a digital signal of 0. land lens 0 prism laser diode 1 prism Lightsensing diode Lectured by Prof. Jese Role @ UEAB 2008 laser diode Lightsensing diode
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 Lectured by Prof. Jese Role @ UEAB 2008
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) 40 X range of current rates 40 X 150 KB per second = 6, 000 KB per second or 6 MB per second 75 X 75 X 150 KB per second = 12, 250 KB per by Prof. Jese or 12. 25 MB per second Lectured second Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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-RAM A rewritable DVD that allows you to erase and record on the disc multiple times DVD+RW A competing technology to DVD-RAM Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
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 Lectured by Prof. Jese Role @ UEAB 2008
Miniature Mobile Storage Media What is miniature mobile storage media? ° Handheld devices use miniature mobile storage media to augment internal storage Device Name Clik! Disk Storage Capacity 40 MB Type, Use Cartridge Digital cameras, notebook computers Compact. Flash Microdrive 2 to 256 MB 1 GB Memory Card Digital cameras, handheld computers, notebook computers, printers, cellular telephones Memory card Digital cameras, handheld computers, music players, video cameras Smart. Media 2 to 128 MB Lectured by Prof. Jese Role @ UEAB 2008 Memory Card Digital cameras, handheld computers, photo printers, cellular telephones
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