Hardware Basics:

1
Chapter 2

• Hardware Basics
• Inside the Box

2.01
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After reading this chapter, you should be able
to

• describe the basic structure of a computer
• discuss the functions and interactions of
  principal computer components
• explain why a computer typically has different
  types of memory and storage devices and give
  examples of each

2.02
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How It Works boxes

• How It Works boxes in your textbook provide more
  technical detail than the main text has to offer.
• How It Works boxes use text and graphics to
  further explore the inner workings of the
  computer.

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Chapter Outline

• What Computers Do
• A Bit About Bits
• The Computers Core CPU and Memory

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What Computers Do

• Computers are used to carry out complex
  functions.
• Despite their appearent complexity, computers can
  only really do four things
• Receive input.
• Process information.
• Produce output.
• Store information.

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Receive Input

• Computers accept information from the outside
  world.
• The keyboard is the most common input device.
• Pointing devices like the mouse also receive
  input.

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Process Information

• The central processing unit (CPU) performs all
  arithmetic calculations and logical decisions.
• The CPU is like the brain of the computer.

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Produce Output

• Computers produce information and send it to the
  outside world.
• A video monitor is a common output device.
• Printers also produce output.

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Store Information

• Information in a computers memory can be moved
  and stored at a new location.
• Primary storage is the computers memory.
• Secondary storage is data on disks.

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A Bit About Bits

• The computer uses a binary (two-digit) system.
• Binary digits, or bits, can represent numbers,
  codes, or instructions.
• The two digits, 0 and 1, represent the two states
  of a switchoff and on.

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Bits as Numbers

• The decimal sysem uses ten digits to represent
  numbers.
• 0, 1, 2 , 3 , 4 , 5 , 6 , 7 , 8 , and 9
• People use this system.
• The binary system uses two digits to represent
  the numbers 0 and 1.
• Computers also use the binary system.

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Bits as Codes

• Characters can be represented as bit codes.
• A 01000001
• 5 00110101
• Color, sound, and graphics can also be converted
  into bit code.

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Bits as Instructions

• Programs can also be stored as collections of
  bits.
• For instance, 01101010 might instruct the
  computer to add two numbers.
• Other bit instructions might include where to
  find numbers stored in memory or where to store
  them.

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Bit-related Terminology

• These terms might describe file size or memory
  size
• Bit smallest unit of information
• Byte a grouping of eight bits of information
• K (kilobyte) about 1,000 bytes of information
• MB (megabyte) about 1 million bytes of
  information
• GB (gigabyte) about 1 billion bytes of
  information

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The Computers Core The CPU and Memory

• The CPU is located on the motherboard.
• Functions
• Interpret and carry out program instructions.
• Do arithmetic calculations.
• Perform logical data manipulations.
• Communicate with other parts of the computer
  system.

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Factors Influencing the CPU

• Compatibility
• Not all software is compatible with any given
  CPU.
• New microprocessors can usually run older
  software.
• New software is not usually compatible with old
  microprocessors.
• Speed
• Speed is determined by the internal clock of a
  computer and is measured in megahertz.
• The architecture of a computer determines its
  speed.

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Primary Storage The Computers Memory

• RAM (random access memory)
• is the most common memory chip.
• will not remain if power goes off.
• must move data onto a disk if it is to be saved.
• ROM (read-only memory)
• information is stored permanently on a chip.
• contains startup information and other permanent
  data.

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Buses, Ports, and Peripherals

• Peripherals
• are external devices for receiving input or
  producing output (keyboard, monitor, and mouse).
• communicate with other parts of the system.
• provide attachment and communication with
  external devices by means of
• slots (for internal attachment)
• ports (for external attachments)

2.18