Computer Hardware

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Chapter 1

• Computer Hardware

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Whats inside and on the CD?

• In this chapter, you will
• Gain an overview of computer equipment and
  terminology
• Learn how computers are classified
• Learn how personal computers fit into the gamut
  of machines from PDAs to supercomputers
• Review basics components of a typical personal
  computer system
• Look inside the system unit
• Explore advantages and disadvantages of several
  computer storage devices
• Learn some basics about maintaining your computer
  and troubleshooting problems

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What is a computer?

• A device that
• Accepts input
• Processes data
• Stores data
• Produces output

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What is a computer?

• Computer input is whatever is typed, submitted,
  or transmitted to a computer system
• Data refers to symbols that represent facts,
  objects, and ideas
• Processing is manipulation of data
• Most takes place in central processing unit
  (CPU), a computers brain
• Computer programs are instructions that tell
  computers how to process

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What is a computer?

• An operating system is software that helps a
  computer operate efficiently and keep track of
  data
• Application software helps users apply
  computers to specific tasks
• Memory is temporary storage
• Storage is permanent
• Computer output is results produced by computer

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What is a computer?
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How are computers classified?

• Computers are divided into five categories
• Handheld computers
• Personal computers
• Servers
• Mainframe computers
• Supercomputers

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How are computers classified?

• Handheld computer (PDA) features include
• Small keyboard or touch-sensitive screen
• Designed to fit in your pocket
• Runs on batteries
• Used while holding it

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How are computers classified?

• A personal computer is designed to meet the
  computing needs of an individual
• Desktop computers fit on desks and run on power
  from wall outlets
• A Notebook computer (laptop) incorporates screen,
  keyboard, storage, and processing

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How are computers classified?

• A tablet computer is portable, featuring a
  touch-sensitive screen used for writing or drawing

• A server is to serve data to computers connected
  to a network

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How are computers classified?

• A mainframe computer is capable of simultaneously
  processing data for hundreds or thousands of
  users
• A supercomputer is one of the fastest computers
  in the world and can tackle complex tasks

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Can computers connect to each other?

• A PDA can connect to desktop with a cable or
  wireless link
• Personal computers can connect to each other or
  larger computers via wired or wireless computer
  networks
• A computer network can be as few as two or as
  many as thousands of computers
• The Internet is the worlds largest network,
  connecting millions of computers

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Can computers connect to each other?

• Computers can be connected using a centralized
  model or a distributed model
• A Centralized computing system depends on a
  centrally-located computer for processing and
  storage
• A distributed computer network spreads the
  processing and storage tasks among many computers

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Can computers connect to each other?
Centralized computer system
Distributed computer network
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Can computers connect to each other?

• Large-scale centralized and distributed computer
  systems are used for many tasks
• Government applications include tax roles, census
  records, and vehicle registration
• Commercial applications include inventory,
  payroll, and point-of-sale

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Can computers connect to each other?

• Large-scale centralized and distributed computer
  systems are used for many tasks (contd)
• Hospital and healthcare organizations
  applications include patient records, integrated
  diagnostic tools, patient billing, and health
  insurance claims processing
• In education, applications include course
  registration, student records, budgeting, and
  payroll

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What are the components of a personal computer
system?

• Included in a typical personal computer system
  are
• System unit
• Display device
• Keyboard
• Mouse
• Storage devices
• USB ports
• Sound card and speakers
• Modem
• Network card
• Printer

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What are the components of a personal computer
system?
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Whats inside the system unit?

• The System contains storage devices, a power
  supply, and main circuit board (motherboard)
• Computer chip, microchip, and chip are
  technical jargon for an integrated circuit
• An integrated circuit is a super-thin slice of
  semi-conducting material packed with microscopic
  circuit elements

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Whats inside the system unit?
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How do computer circuits manipulate data?

• Most computers are electronic, digital devices
• Digital devices work with discrete data, such as
  digits 1 and 0, or like a light switch on or
  off
• Analog devices work with continuous data, like a
  dimmer switch with continuous range

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How do computer circuits manipulate data?

• Most computers use simplest technology of two
  possible states, like on-off switch
• Usually we indicate on state as 1 and off
  state as 0
• These 1s and 0s are referred to as binary digits
  or shortened to bits
• Computers use sequences of bits to digitally
  represent numbers, letters, punctuation marks,
  music, pictures, and videos

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How do computer circuits manipulate data?

• Computers employ several codes to represent
  character data, including
• ASCII requires only seven bits for each
  character
• Extended ASCII requires eight bits for each
  character
• EBCDIC is eight-bit technology used on older,
  IBM mainframe computers
• Unicode uses sixteen bits and provides code for
  65,000 characters

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How do computer circuits manipulate data?
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What factors affect computer speed, power and
compatibility?

• Computers have three major components
• Processor
• Memory
• Storage
• When a program is started, it is moved from
  storage to memory
• The processor fetches program instructions from
  memory, then begins to execute

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What factors affect computer speed, power and
compatibility?

• If instructions require data, the processor
  fetches it from memory, loads it into memory,
  then transfers it to the processor
• The results are sent back to memory
• The results can be stored or sent to output
  printer or screen

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What factors affect computer speed, power and
compatibility?

• Speed and efficiency of processing cycle can be
  affected by factors such as
• Microprocessor type and speed
• Memory capacity
• Hard disk drive speed and organization
• Display capability and video memory
• Network and modem connection speed

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What factors affect speed and power?

• Bit is abbreviated as lowercase b
• Byte is composed of eight bits and is abbreviated
  by uppercase B
• These abbreviations combined with kilo produce
  specifications such as KB (kilobyte) and Kb
  (kilobit)

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What factors affect speed and power?

• In world of computers kilo means 1024, not 1000
• Kilobit is 1024 bits and kilobyte is 1024 bytes
• Kilobytes is often used when referring to size of
  small computer files

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What factors affect speed and power?

• Prefix mega means a million, or in context of
  bits and bytes, 1,048,576
• Megabits is used when referring to speed of data
  transmission
• Megabytes is used when referring to file size, CD
  capacity, or video card memory capability

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What factors affect speed and power?

• Giga refers to a billion or 1,073,741,824
• Gigabytes are used to describe RAM, DVD, and hard
  disk capacity
• Mainframe and supercomputers use tera-
  (trillion), peta- (quadrillion), and exa-
  (quintillion)

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What factors affect speed and power?
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What factors affect speed and power?

• The three most popular personal computer
  platforms are PCs, Macs, and Linux
• The PC platform is based on the design of the IBM
  PC
• The Mac platform is based on a proprietary design
  for the Macintosh
• The Linux platform is a standard PC with the
  Linux operating system
• Compatible computers operate in essentially the
  same way

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Whats important about microprocessors?

• The most important, and usually the most
  expensive, component of a computer
• Circuitry is grouped into important functional
  areas
• ALU ( arithmetic logic unit) performs arithmetic
  operations
• Uses registers to hold data that is being
  processed
• Control unit fetches each instruction

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Whats important about microprocessors?

• Microprocessor speed is measured in megahertz
  (MHz) or gigahertz (GHz)
• MHz 1 million cycles per second
• GHz 1 billion cycles per second
• During each cycle the microprocessor executes
  instruction
• The faster the clock speed, the more instructions
  executed per second

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Whats important about microprocessors?

• Microprocessors are also rated by word size
• Many process a 32-bit word
• 64-bit available, and are faster then 32-bit
  units
• Microprocessors manufactured by several
  companies
• Intel
• AMD
• Motorola
• IBM

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Whats important about microprocessors?
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Whats important about computer memory?

• RAM (random access memory) is temporary holding
  area for data, application programs instruction,
  and operating system
• RAM is waiting room for processor
• When program is started, it is held in RAM until
  needed and remains there until program is closed

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Whats important about computer memory?

• RAM also holds data
• Most RAM is volatile, which means it needs
  electrical power to hold data
• If power goes out, or computer is turned off,
  data stored in RAM is instantly and permanently
  lost
• It is important to frequently save work to a
  permanent storage area, such as hard disk, as you
  work

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Whats important about computer memory?

• RAM also holds operating system instructions,
  loaded each time you turn on your computer and
  held until it is turned off
• RAM capacity is measured in megabytes or
  gigabytes
• Todays computers have between 512 megabytes and
  4 gigabytes of RAM

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Whats important about computer memory?
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Whats important about computer memory?

• Most computers also contain ROM (read only
  memory) a type of memory that holds the
  computers startup routine
• Whereas RAM is temporary and volatile, ROM is
  permanent and non-volatile

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Why do computers use multiple storage devices?

• Computers feature multiple storage devices such
  as
• Hard disk drive is the main storage device in
  most computers
• Provides lots of storage capacity
• Provides fast access to files
• Economical
• Capacity is measured in gigabytes and speed in
  milliseconds (ms) or revolutions per minute (RPM)

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Why do computers use multiple storage devices?
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Why do computers use multiple storage devices?

• A CD (compact disk) provides 650-700 MB of
  storage
• A DVD (digital video disk or digital versatile
  disk) is a variation with a capacity of 4.7 GB
• CDs and DVDs are durable storage
• Unaffected by magnetic fields
• Dust and dirt can be cleaned off
• Biggest threat are scratches

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Why do computers use multiple storage devices?
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Why do computers use multiple storage devices?

• CDs and DVDs come in several varieties
• Read only (ROM) permanent data stored during
  manufacturing
• Recordable (R) A writable drive can store data
  but it cant be changed
• Rewritable (RW) can be changed many times, much
  like a hard drive but much slower

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Why do computers use multiple storage devices?

• A USB flash drive is a popular removable,
  portable storage device
• About the size of a highlighter pen
• Very durable
• Open, edit, delete, and run files just as if they
  were on hard drive
• Plugs into USB port
• Provides fast access to data and uses little power

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Why do computers use multiple storage devices?

• In addition to storage devices connected to
  computer, data can be stored on online storage

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What kind of protection and maintenance does a
computer require?

• Large organizations protect equipment from theft
  with high-tech security systems
• Protect personal computer by locking to desk or
  locking room
• When traveling by air, carry it in your carry-on
  bag

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What kind of protection and maintenance does a
computer require?

• Make sure computer is balanced safely on desk or
  resting on floor
• When carrying notebook computer, use padded
  carrying case
• When transporting desktop, use original box or
  protect it with foam padding

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What kind of protection and maintenance does a
computer require?

• Environmental factors can do damage
• Excess heat can damage circuitry
• Excess humidity combined with salt air can
  corrode contacts
• Magnetic fields can erase data
• Dust and dirt can cause overheating and clog up
  mechanical parts

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What kind of protection and maintenance does a
computer require?

• Routine cleaning of mouse and keyboard can keep
  them working smoothly
• Follow manufacturers instructions for cleaning
  to keep printer from jamming and print head from
  smearing
• Keep floppy disks and hard disks away from strong
  magnetic fields

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What kind of protection and maintenance does a
computer require?

• Computers are vulnerable to power irregularities
• Make sure power cable is positioned so it cant
  be accidentally disconnected
• When going to another country, ensure your
  equipment conforms to power systems
• Use surge strips to protect against power spikes
  and surges
• To protect against power outages, you can connect
  to uninterruptible power supply

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What kind of protection and maintenance does a
computer require?

• Owners should periodically make backups of data,
  run a defragmentation utility, and update virus
  checking software
• Consider following guidelines when
  troubleshooting
• Make sure equipment is plugged in
• Check all cables
• Get clear idea of problem by trying to isolate
  malfunctioning device or replicating steps

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What kind of protection and maintenance does a
computer require?

• Attempt basic solutions, such as restart device
  or rebooting
• Look for information in manuals, the Web, or
  manufacturers support line
• When communicating with technicians, explain
  problem accurately and prepare to answer
  questions about brand, model, operating system,
  and application software

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What kind of protection and maintenance does a
computer require?

• Follow instructions carefully and completely
• Before you resume normal operations, make sure
  problem is fixed
• If possible, take steps to avoid similar problems
  in the future

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