Transcript Processor

Discovering
Computers 2012
Your Interactive Guide
to the Digital World
Objectives Overview
Differentiate among various
styles of system units on
desktop computers,
notebook computers, and
mobile devices
Identify chips, adapter
cards, and other
components of a
motherboard
Identify characteristics of
various personal computer
processors on the market
today, and describe the
ways processors are cooled
See Page 209
for Detailed Objectives
Describe the control unit
and arithmetic logic unit
components of a processor,
and explain the four steps in
a machine cycle
Define a bit and describe
how a series of bits
represents data
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The System Unit
• The system unit is a case that contains electronic
components of the computer used to process data.
• Made of metal or plastic to protects the
internal components from damage.
• All computers have a system unit. It is available
in variety of shapes & sizes.
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Figure 4-1
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The System Unit
• The inside of the system unit on a desktop
personal computer includes:
Drive bay(s)
Power supply
Sound card
Video card
Processor
Memory
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Figure 4-2
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Motherboard
• The motherboard is the
main circuit board of the
system unit.
• Contains expansion slots,
processor chips, and
memory slots
• Sometimes called a
system board
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Motherboard
•
Most computers use integrated circuits also called chips ,
for their CPU and main memory.
•
Memory chips are installed on memory module( card)
that fit in a slot on the mother board.
• What is a chip?
•
Small piece of semi-conducting material on which
integrated circuits (IC) are etched.
•
IC contain many microscopic pathways capable of
carrying electrical current.
• Each IC can contain millions of elements such as resistors,
capacitors, transistors.
Next
Processor
• The processor, also called the central processing
unit (CPU), interprets and carries out the basic
instructions that operate a computer
– Contain a control unit and an arithmetic logic unit
(ALU) that work together to perform processing
operations
Multi-core
processor
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Dual-core
processor
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Quad-core
processor
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Processor
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Figure 4-4
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Processor
• The control unit is the component of the processor
that directs and coordinates most of the operations
in the computer.
– Handles the transmission of data into and out of the CPU
and supervises its overall operations.
– Its interprets each instruction issued by a program & then
initiates the appropriate action to carry out the
instruction.
• The arithmetic logic unit (ALU) performs arithmetic,
comparison, and other operations.
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Processor
• For every instruction, a processor repeats a set of
four basic operations, which comprise a machine
cycle
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Figure 4-5
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Processor
The processor contains registers, that
temporarily hold data and instructions
The system clock controls the timing
of all computer operations
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Processor
Registers
• The registers are special storage areas in the CPU.
• Their function is to hold instructions, data values, memory
addresses of both the instructions and data.
• There are 4 basic types of it: CU, ALU
• Instruction register hold instruction
• Address register hold address of( data , next instruction ).
• Storage register store data retrieved from main memory prior to
processing.
• Accumulator store the results of arithmetic & logic operations
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Processor
System clock
• It generates regular electronic pulses , or ticks,
that control the timing of all computer operations
( i.e. set operating pace of components of system
unit)
• Pace of system clock is clock speed. Most clock speeds
are in the gigahertz (GHz) range (1 GHz = one
billion ticks of system clock per second).
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Processor
• Most current personal
computers support
pipelining
– Processor begins
fetching a second
instruction before it
completes the machine
cycle for the first
instruction
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Figure 4-6
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Processor
• Parallel processing uses multiple processors
simultaneously to execute a single program or task
– Massively parallel processing involves hundreds or thousands of
processors
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Processor
• The leading
manufacturers
of personal
computer
processor chips
are Intel and
AMD
Pages 216 – 217
Figure 4-7
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Processor
• Determine
how you
plan to use a
new
computer
before
selecting a
processor
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Figure 4-8
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Processor
• A processor chip
generates heat that
could cause the chip to
burn up
• Require additional
cooling
– Heat sinks
– Liquid cooling
technology
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Figures 4-9 – 4-10
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Data Representation
Analog signals are continuous and vary in strength and quality
Digital signals are in one of two states: on or off
• Most computers are digital recognize only two discrete states: on or off.
• Use a binary system to recognize two states
• Use number system with two unique digits: 0 and 1, called bits (short for
binary digits)
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Data Representation
A computer circuit represents
the 0 or the 1 electronically by
the presence or absence of an
electrical charge
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Figures 4-12 – 4-13
Eight bits grouped together as a
unit are called a byte. A byte
represents a single character in
the computer ( numbers, upper
or lower case letters, or
punctuation marks)
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Data Representation
• The different combinations of 0s and 1s are defined by patterns
called a coding schema.
• There are two coding schemas used to represent data

ASCII—American Standard Code for Information Interchange
[Personal Computers – PCS]

EBCDIC—Extended Binary Coded Decimal Interchange Code
[Mainframes, Mini-computers]
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Figure 4-14
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Data Representation
• ASCII is the most widely used coding scheme to
represent data
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Figure 4-14
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Data Representation
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