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					Hardware Designed to
   Meet the Need
Learning Objectives
• Understand how bits and bytes are used to
  represent information of value to people
• Identify the functions of the components of a
  CPU, the relationship between the CPU and
  memory, and factors that contribute to
  processing speed
• Identify different types of memory and storage
  media, and understand the unique properties of
  each

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Learning Objectives
• Identify different types of input and output
  devices and how they are used to meet a variety
  of personal and professional needs

• Understand the decision-making process
  involved in purchasing a computer system




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Representing Characters and
Values with Bytes
• Bits
   – Typically organized into groups of eight called bytes
• American Standard Code for Information Interchange (ASCII)
   – Code representing keyboard text characters
• Binary number system
   – Uses only two values, 0 and 1
   – Used by computers and digital devices to represent and process data
• Hexadecimal number system
   – Uses 16 values, 0 through 9, A through F (e.g. 9D3A)
   – Easy representation of Binary number system



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Representing Characters and
Values with Bytes




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Bits, Bytes, and People
• Digital convergence
  – Merging multiple digital services into one device
     • At home
        – Single device can be used for audio and video, computing, and
          information access
     • At work
        – Used to combine voice, video, text communications and
          information on a single network




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Integrated Circuits and Processing
• The ability to digitize information is at the heart
  of the digital revolution
  – Information is useless without the ability to process it
    into useful forms
• The quality of digital electronic devices is
  typically a reflection of the speed of its processor
  – The faster the processor, the faster and more robust
    the service
  – Many of the advances and new features in today’s
    technology is due mainly to faster processors
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Integrated Circuits and Processing




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Integrated Circuits
• Transistor
  – Composed of semiconducting material that opens or
    closes a circuit to alter the flow of electricity to store and
    manipulate bits
• Integrated circuits
  – are multiple transistors integrated into a single
    module used to store and process bits and bytes in
    today’s computers
  – Also called chips


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Integrated Circuits
• Central processing unit
  – Group of integrated circuits that perform processing,
    it progresses through the program’s sequence of
    instructions
• Microprocessor
  – CPU circuits packed onto a smaller module
• Motherboard
  – Primary circuit board of a computing device



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Integrated Circuits




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The Central Processing Unit and
Random Access Memory
• Processing
   – Manipulating data as defined by program instructions
• Instruction set
   – Number of instructions the processor is to carry out
• Arithmetic/logic unit (ALU)
   – Contains the circuitry to carry out instructions, such as mathematical and
     logical operations
• Control unit
   – Sequentially access and decodes program instructions
   – Coordinates flow of data in and out of ALU
   – accesses and decodes program instructions, and coordinates the flow of
     data among various system components

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The Central Processing Unit and
Random Access Memory
• Registers hold the bytes currently being
  processed
• Multicore design
  – Housing more than one CPU on a chip
  – Dual-core processors and quad-core processors
• Random access memory
  – Temporary, or volatile storage
• Front side bus
  – Electronic pathways between the CPU and RAM

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The Central Processing Unit and
Random Access Memory




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The Machine Cycle
• Execution of an instruction involves two phases:
  – Instruction phase, execution phase
  – Two phases together make up the machine cycle
     • Instruction phase
        – Step 1: Fetch instruction
        – Step 2: Decode instruction
     • Execution Phase
        – Step 3: Execute instruction
        – Step 4: Store results




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The Machine Cycle




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CPU Characteristics
• System clock
  – Produces a series of electronic pulses at a
    predetermined rate called clock speed
• Clock speed
  – Measured in megahertz (MHz) or gigahertz (GHz)
• Processor numbers
  – Used to market processors instead of clock speed
• Cache memory
  – High-speed memory a processor can access more
    quickly than RAM

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CPU Characteristics
• Wordlength
  – Number of bits that a CPU can process at once
• Millions of instructions per second (MIPS)
  – Amount of time it takes to execute an instruction
• Floating-point operations per second (FLOPS)
  – More precise than MIPS
  – Gigaflop, teraflop (speed of the fastest
    supercomputers today)


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CPU Characteristics




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Multiprocessing and Parallel Processing
• Multiprocessing
  – Uses more than one processing unit
• Parallel processing
  – Links several microprocessors to operate in parallel
• Coprocessors
  – Special-purpose processors that speed processing




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Multiprocessing and Parallel Processing
• Massively parallel processing (MPP)
  – Uses hundreds or thousands of processors operating
    together
• Grid computing or clustering
  – Allows processors from different computers to work
    together over a network on complex problems




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Multiprocessing and Parallel Processing




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Physical Characteristics of the CPU
• CPU speed
  – Collections of digital circuits imprinted on silicon
    wafers, or chips
  – To turn a digital circuit on or off
     • Electrical current must flow through a medium from Point
       A to Point B
• Moore’s law
  – Continued increase in technological innovations
    causes transistor densities in an integrated circuit to
    double every two years

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Physical Characteristics of the CPU




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Storage – System Storage
• Storage is the ability to maintain data within the
  system permanently or temporarily
• System storage
  – Storage used by computer system for standard
    operations
     • RAM, cache, video RAM, ROM, CMOS
     • RAM has the largest capacity




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RAM SIMMs and DIMMs
• RAM SIMMs
  – Set of chips grouped together on a circuit board
• RAM DIMMs
  – 64-bit data path
  – Twice that of a SIMM
• There are many types of RAM
  – DRAM, SDRAM, RD-RAM, DDR-SRAM, FPMRAM,
    EDO-RAM…



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RAM SIMMs and DIMMs




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Graphics Memory
• Graphics Memory
  – Sometimes called video RAM or VRAM
  – Stores image data to speed the processing of video images
  – Acts as a buffer, or intermediate storage area between the
    microprocessor and the display
• Graphics processing unit (GPU)
• Graphics card or video card: one kind of adapter
  card
  – Contains the graphics memory, GPU, other graphic hardware



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Graphics Memory




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System Storage
• Read-only memory (ROM)
  – system memory that provides permanent storage for
    data and instructions
  – system memory used to store boot programs and
    data(hardware configuration information) from the
    computer manufacturer, including the boot process
    used to start the computer (BIOS)
  – Flash BIOS: Intended to store data permanently can
    be updated



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CMOS Memory
• CMOS memory
  – Semi-permanent storage for information that may
    change
  – Uses battery power
  – Able to keep accurate time and date even when
    computer is shut down




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Secondary-Storage Technologies
• Storage device
  – Drive that reads and writes data
• Storage media
  – Objects that hold the data (disks)
• Storage capacity
  – Maximum amount of bytes medium can hold
• Access time
  – Time it takes for a request for data to be fulfilled by
    the device




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Access Method
• Direct access: access data directly (fast)
  – E.g. disk
• Sequential access: access data n sequence (slow)
  – E.g. tape, used for back-up




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Magnetic Media: Disks and Tapes
• Magnetic storage devices
  – uses properties of iron oxide particles to store bits
    and bytes more permanently than RAM
• Floppy disks
  – Portable, low-capacity, direct storage medium
• Microdrives
  – Tiny hard drives that store data on a small disk
• Magnetic tape can be used to store vast
  quantities of data
  – an example of a sequential access storage medium

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Magnetic Media: Disks and Tapes
• Storage area network or SAN
  – Links together many storage devices over a network
    and treats them as one large disk
  – Used to store all RU accounts as back-up
• RAID or redundant array of independent disks
  – Uses a second system of disks to maintain a backup
    copy of the data stored on the primary disks
  – used to store database



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Magnetic Media: Disks and Tapes




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Optical Storage
• Uses optical laser to burn pits into the surface of
  a highly reflective disk
• Compact disk read-only memory (CD-ROM)
  – Optical media that stores up to 700 MB of data
• Digital video disk (DVD)
  – Backward-compatible with CD-ROMs
  – DVD-ROM: can store over 4.7 GB of data


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Optical Storage
• HD DVD and Blu-ray DVD
  – Able to read smaller pits, which allows for greater
    capacity
• CD-RW
  – RW: indicate that a disk can be rewritten numerous
    times
  – Most popular format for writable CDs
  – can be rewritten numerous times just as you would a
    hard drive
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Optical Storage




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Solid State Secondary Storage
• Solid state storage devices store data using transistors
   – can be volatile (as with RAM), or nonvolatile (as with flash
     memory)
• Secondary solid state storage stores the data without
  the need for electricity
   – Flash memory
      • Updates the data it holds in large blocks
      • Requires no moving parts, is faster than other forms of secondary
        storage, and requires less energy
   – Flash memory card
      • Keeps its memory when the power is shut down


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Solid State Secondary Storage
• Flash drive
  – Also called USB (Universal Serial Bus, USB port: standard that allows a wide
    array of devices to connect to a computer through a common port) or
    thumb drive
  – A small memory module, about the size of your thumb or smaller, that
    conveniently plugs into the USB port of a PC or other digital electronics
    device to provide convenient, portable, high-capacity storage

• Solid state disk
  – Uses flash technology to replace magnetic hard drives

• Hybrid drive
  – Combines best features of magnetic and flash memory storage
  – Solid state notebooks


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Evaluating Storage Media:
Access Method, Capacity, and Portability
• Your needs determine your storage
  requirements
  – Credit card company needs fast access
  – Hospital needs portability, capacity, and privacy
• Faster access is more expensive
• Trend: smaller, higher capacity, faster, cheaper




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Access Method, Capacity, and Portability




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Input, Output and Expansion:
Input and Output Concepts
• Input device
  – Assists in capturing and entering raw data into the
    computer system
• Output device
  – Used to observe results of computer processing with
    one or more of your senses
• The goal is speed and functionality


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Input and Output Concepts
• The nature of data
  – Human-readable
  – Machine-readable
• Source data automation
  – Ensures accuracy and timeliness by automating data
    entry where data is created
     • Scanners to check out library materials




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Input and Output Concepts




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Input Devices
• General-purpose and special-purpose I/O devices
  – Personal computer input devices
     • Ergonomic keyboard
        – Designed to reduce stress on the wrist

  – Trackball
     • Allows you to control the mouse pointer by rolling a
       mounted ball
     • permit pointer movement through finger motion without
       much arm motion



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Input Devices
• Graphics tablets
  – Allow you to draw with a pen-like device on a tablet
• Mobile Input Devices
  – Notebook computers integrate the mouse either as a
    touch pad or a touch screen




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Input Devices
• Microphone input devices
  – Speech recognition software
  – Voice recognition
• Gaming
  – Game controller or joystick
• Digital cameras
  – The more megapixels, the higher the price
• Digital camcorders and Webcams


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Input Devices
• Scanning devices
  – Page scanners and handheld scanners
     • Both can convert monochrome and color pictures, forms,
       texts, and other images into digital images
• Character recognition software
  – Transforms scanned documents into editable
    documents
• Special-purpose scanners
  – Magnetic ink character recognition, optical mark
    recognition, point-of-sale devices
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Input Devices




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Output Devices
• Display resolution
   – Measure of the number of pixels on the screen
   – Dot pitch measures space between pixels

• High-definition television and monitors
   – Twice the resolution of regular TVs

• Liquid crystal display (LCD), or flat panel display
   – Quickly displacing CRT (cathode-ray tube) displays
   – A thin, flat display that uses an organic, oil-like material placed
     between two pieces of glass to form characters and graphic
     images on a backlit screen
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Output Devices
• Plasma display
  – Similar to LCD, but uses plasma rather than liquid
    crystal between the flat panels
• LED display
  – Used in thin displays to provide backlight with lower
    power usage and truer color
• LCD projectors
  – Used for projecting presentations from your
    computer onto a larger screen

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Output Devices
• Printers and Plotters
   – Used to create hard copy, or paper output
   – Ink-jet and laser printers
• Photo printers
• Multifunction printers
   – Combine printer, fax machine, copier, and digital scanner
• Plotters are used for printing large graphic designs
• 3D printers use CAD blueprints as input, and can output
  an actual 3D prototype


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Output Devices
• Computer sound systems
  – Used to draw user’s attention to important
    information and to support sound for entertainment
     • CD/MP3
     • DVD
     • Gaming
  – People with limited vision
     • Screen reading program, JAWS




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Output Devices




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Special-purpose I/O Devices
• Many designed for scientific and medical research
• Computer scientists and musicians at the MIT Media
  Lab
   – Experimenting with special input devices
• Virtual reality headset
   – Can project output in three-dimensional color images
• Wearable PCs
   – Fit in a pack or clip to a belt



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Special-purpose I/O Devices




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Expansion
• Desktop expansion
  – USB
     • Provides connection to computer for data transfer
     • Provides power line
  – Expansion board or expansion card
     • Circuit boards for more specialized devices
     • Expansion slots
  – Firewire (for digital camera)
     • Competes with USB as standard for connecting devices to
       PCs


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Expansion slots

• PCI slots (white)




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Mobile Computer Expansion
• Notebook computers
  – PCMCIA slots that accept PCMCIA cards
  – Ports also included for standard devices
• Handheld computers
  – GPS, Internet, webcams, LCD projectors
  – All the peripherals available for notebooks




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Researching a Computer Purchase
• Determine the needs first
   – How much data stored (e.g. Hospital data: terabytes)
• To learn about computer type and platform
   – www.cnet.com
   – www.zdnet.com
• To learn about manufacturers
   –   Computer shopper magazine
   –   MacWorld magazine
   –   www.gateway.com
   –   www.dell.com
   –   www.apple.com
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Researching a Computer Purchase




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Online Vendors
• Online vendors
  – Allow customer to configure and purchase directly
    from the manufacturer, often saving you money
  – Custom configure your PC
  – Service options
• Online computer retailers
  – Quickly and easily compare packages
  – Good way to scout out and compare computer prices
• Auction sites

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Local Vendors
• Local vendors offer advantages
  – Allow you to try before you buy
  – Advice from qualified sales staff
  – Sales, package deals, incentives
  – Simpler to return if necessary
• The downside – little or no opportunity to
  customize



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Payment Options
• There are various payment options available
  both in the store and online
  – Cash, credit
  – Computer loans
  – Trade-in options




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Summary
• Digital revolution
  – Sparked by computer’s ability to represent and
    manipulate information digitally, with 1s and 0s
• CPU
  – Processes data into information that is meaningful
  – Control unit uses the four-step machine cycle to carry
    out program instructions
     • Fetch instruction, decode instruction
     • Execute instruction, and store results


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Summary
• Identify and understand the unique properties of
  different types of storage media and memory
  – RAM
     • Volatile and temporarily stores data
  – ROM
     • More permanent storage
  – Optical storage
     • Includes CDs and DVDs




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Summary
• Input devices
  • Provide data and instructions to computer
• Output devices
  – Receive results from computer
• When selecting a computer system
  – Analyze your specific computing needs
  – Online vs. local
  – Payment options


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