Essential Introduction to Computers

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Essential Introduction to Computers
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Chapter Concepts

• Definitions
• Computer
• Data and information
• Four basic computer operations input,
  processing, output, and storage
• Principal components of a computer and their use
• Storage media magnetic disks, optical disks,
  USB flash drives, and other types

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Chapter Concepts (cont.)

• Computer software
• System software
• Application software
• Computer communications channels and equipment
• The Internet and World Wide Web
• E-commerce

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What is a Computer?

• An electronic device, operating under the control
  of instructions stored in its own memory, that
  can do four basic operations
• Accept data (input)
• Process the data according to specified rules
  (process)
• Produce results (output)
• Store the results for future use (storage)

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Benefits of a Computer

• Speed
• Reliability
• Accuracy
• Huge storage capability
• Communications capability

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The Physical Components of a Computer

• Input devices
• Output devices
• Processor
• Central Processing Unit (CPU)
• Arithmetic/Logic Unit (ALU)
• Memory (sometimes called internal memory
• Storage devices (sometimes called external
  memory)
• Communications devices
• Some components, such as the processor, internal
  memory, and some storage devices are housed in a
  box-like case called the system unit

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Components of a Computer
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Memory versus Storage

• Memory (internal memory)
• Electronic
• Transient (only lasts while the power is on)
• Expensive (thus relatively small capacity)
• Storage (external memory)
• Non-electronic (generally magnetic or laser)
• Persistent (can last a very long time)
• Can be very cheap (thus very large capacity)

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Input Devices

• An input device is any hardware component that
  allows you to enter data, programs, commands, and
  user responses into a computer
• Keyboard
• Mouse
• Touchpad
• Microphone
• Digital camera
• Stylus
• Touch screen
• Others

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Output Devices

• An output device is any hardware component that
  makes the information resulting from processing
  available for use
• Monitor
• CRT (cathode ray tube)
• LCD (liquid display crystal) flat panel
• Printer Impact, non-impact
• Speakers
• Others

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Processor

• The central processing unit (CPU) interprets and
  carries out the basic instructions that operate a
  computer. Comprised of
• Control unit carries out instructions
• Arithmetic/logic unit (ALU) does math and
  comparisons

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Memory

• RAM (random access memory) consists of electronic
  components that temporarily store instructions
  waiting to be executed by the processor, data
  needed by those instructions, and the results of
  processed data

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System Unit
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Storage Devices (External Memory)

• A storage device is used to store instructions,
  data, and information for the long term. Current
  media are
• Magnetic
• Optical
• Infrequently, other
• Storage media may be
• Non-removable without powering off the computer
  (hard drive)
• Removable (USB drive, floppy disk, CD/DVD disk,
  tape)
• Off-line stored in a long term location, such
  as a businesss archived backups

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Magnetic Storage Media

• Hard disks
• Flash cards
• Smart cards
• Tape
• Floppy disks

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Magnetic Storage Media (cont)

• Disks use magnetic particles to store items on
  the disks surface
• A hard disk is a storage device that contains one
  or more inflexible, circular platters that
  magnetically store data, instructions, and
  information
• A floppy disk is an inexpensive portable storage
  medium
• Tape is a magnetically coated ribbon of plastic
  housed in a tape cartridge

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Magnetic Disk Devices
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Disk Storage Terms

• Platter a disk often a hard drive may have
  multiple platters
• Tracks concentric circles on a disk
• Sectors pie-slice-shaped segments of a track
• Data is found by specifying its platter, track,
  and sector

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Optical Storage Devices

• An optical disc is a portable storage medium that
  consists of a flat, round, portable disc made of
  metal, plastic, and lacquer that is written and
  read by a laser

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Storage Devices

• Miniature mobile storage media are rewriteable
  media usually in the form of a flash memory card,
  USB flash drive, or a smart card

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Communications Devices

• A communications device is a hardware component
  that enables a computer to send and receive data,
  instructions, and information to and from one or
  more computers
• Communication requires a communication device
  (for example, a modem), transmission media
  (wired, wireless), and software

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Software

• A software program is a very detailed sequence of
  instructions that tells the computer what
  operations to perform
• System software
• Applications software

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System Software

• Controls the operations of computer equipment
• Operating system
• Microsoft Windows 7
• Microsoft Windows Vista
• Microsoft Windows XP
• Microsoft Windows CE
• Apple Mac OS X
• Linux
• Unix
• Others
• Drivers

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Application Software

• Application software consists of programs
  designed to make users more productive and/or
  assist them with personal tasks
• Word processing
• Spreadsheet
• Database
• Presentation graphics
• Entertainment (games, music, video, )

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Networks

• A network is a collection of computers and
  devices connected together, often wirelessly, via
  communications devices and transmission media
• Local area network (LAN)
• Wide area network (WAN)

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The Internet

• The Internet is a network of networks that
  connects millions of businesses, government
  agencies, educational institutions, and
  individuals
• Individual connection can be by
• Internet service provider (ISP)
• Online service provider (OSP)
• Wireless Internet service provider (WISP)

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The World Wide Web

• Not a network, but a vast collection of data that
  is accessible through the internet, and usually
  linked together
• Web page a single document
• Web site a group of pages
• Web browser software that displays a web page
• Uniform Resource Locator (URL) the location of
  a desired page

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URLs

• Consists of
• Protocol
• Domain name
• Path
• Page name
• http//go.microsoft.com/fwlink/users/index.htm
• http// is Hypertext transfer protocol
• go.microsoft.com is the domain name
• /fwlink/users/ is the path
• Index.htm is the page name

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Electronic Commerce

• When you conduct business activities online, you
  are participating in electronic commerce, also
  known as e-commerce
• Business to consumer (B2C)
• Consumer to consumer (C2C)
• Business to business (B2B)