tia9e_tif4_under_hood_pptx

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Nov 2, 2013 (3 years and 9 months ago)

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Technology

in Action

Alan Evans



Kendall Martin

Mary Anne Poatsy

Ninth Edition

Copyright © 2013 Pearson Education, Inc. Publishing as Prentice Hall

Technology in Action

Technology in Focus:

Under the Hood

Copyright © 2013 Pearson Education, Inc. Publishing as Prentice Hall

Switches


System unit


Box that contains central electronic
components of the computer


Computer system


Can be viewed as an enormous collection of
on/off switches


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2

Electrical Switches


Computers work with numbers,
not words


Binary language consists of two
numbers: 0 or 1


Electrical switches are devices
that can be switched between

1 and 0 signifying “On” and “Off”


Computers are built from a huge
collection of electrical switches



Lock

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3

Vacuum Tubes


Allow or block flow of electrical current


Take up a large amount of space


Produce heat and burn out frequently


Impractical because of size and reliability

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4

Transistors


Electrical switches built of layers of silicon


Early transistors were built in separate
units as small metal rods


Each rod was a small on/off switch


Smaller and faster than vacuum tubes


Produced less heat



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5

Integrated Circuits


Support huge number of
transistors


Also contain resistors,
capacitors, and diodes


No more than ¼ inch in
size


Over 2 billion transistors
can fit on integrated
circuit

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6


Tiny regions of semiconductor material

Base 10 Number System

10
3

1,000s place

10
2

100s place


10
1

10s place

10
0

1s place


6 * 1,000 + 9 * 100 + 5 * 10 + 4 * 1

(
6,000)
+

(900) + (50) + (4) = 6,954


Base 10 uses 10 digits (0

9)


To represent a number, you break it down
into groups of ones, tens, hundreds, etc.

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7

Base 2 Number System


Base 2 or binary uses two digits (1,0)


Describes value as sum of powers of 2:
1, 2, 4, 8, 16, 32, 64, and so on

2
3

8s place

2
2

4s place


2
1

2s place

2
0

1s place

1

0

1

1

(
8) + (0) +
(
2) + (1) = 11

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8

Base 16 Number System


Hexadecimal notation is used to avoid
working with long strings of 1s and 0s


Base 16 uses 16 digits (0

9 and A

F)


A equals 10, B equals 11, etc.


Values in hexadecimal are much shorter
than binary


Easier for computer scientists to use 43 than
1000011


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9

Windows Calculator


Windows Calculator in
Programmer view:


Converts from decimal
values to binary


67 is 1000011 in binary


Also converts to
hexadecimal notation



67
is 43
in hexadecimal

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10

Representing Characters: ASCII


American Standard Code for Information
Interchange represents each letter or character as
8
-
bit binary code


Each binary digit is called a bit


8 binary digits (or bits) create one byte


ASCII Code

Represents

This Symbol

ASCII

Code

Represents

This Symbol

01000001

A

01100001

a

01000010

B

01100010

b

01000011

C

01100011

C

01011010

Z

00100011

#

00100001

!

00100100

$

00100010



00100101

%

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11

Representing Characters: Unicode


ASCII can use only 256 codes


Unicode uses 1
6 bits and can represent
nearly 1,115,000 code points


Currently assigns more than 96,000
unique character symbols


Unicode can represent alphabets of all
modern and historic languages


Will probably replace ASCII as standard


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12

Representing Decimal Numbers


IEEE established floating
-
point standard


Describes how numbers with fractional parts
should be represented in binary


Uses a 32
-
bit system


First digit used to indicates whether number is
positive or negative


Next 8 bits store magnitude (hundreds,
millions, etc.)


Remaining 23 bits store value of number

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13

CPU Machine Cycle


All
CPUs
perform a
series of similar
steps


Fetch


Decode


Execute


Store


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14

System Clock


Moves CPU from one stage of the
machine cycle to the next


Acts as a metronome, keeping a steady
beat or tick


Ticks, known as the clock cycle, set the pace


Pace, known as clock speed, is measured in
hertz (Hz)


Today’s speed is measured in gigahertz
(GHz), one billion clock ticks per second

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15

Control Unit


Manages switches inside the CPU


Remembers


Sequence of processing stages


How switches are set for each stage


With each beat of system clock, control
unit moves each switch to correct on or off
setting and performs work of that stage

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16

Stage 1: The Fetch Stage


Data and program instructions are stored
in various areas of computer system


Program or data is moved to RAM from
hard drive


As instructions are needed, they are
moved from RAM into registers


Storage areas located on CPU

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17

Cache Memory


Stores recent or
frequently used
instructions


Faster access than
RAM


Advantage is better
performance

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18

Small blocks of memory located directly on
and next to CPU chip

Stage 2: The Decode Stage


CPU’s control unit decodes a program’s
instructions into commands


Instruction set


The collection of commands a CPU can
execute


Written in assembly language


Assembly language is translated into machine
language for the CPU

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19

Stage 3: The Execute Stage


Arithmetic logic unit (ALU)


Mathematical operations


Addition


Subtraction


Multiplication


Division


Test comparisons of values (<, >, =)


Logical OR, AND, and NOT operations


Word size is bits worked with at a time


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20

Stage 4: The Store Stage


Results produced by the ALU in Stage 3
are stored in the registers


Instruction explains which register to use


When entire instruction is completed, the
next instruction will be fetched


The fetch
-
decode
-
execute
-
store cycle
begins again


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21

Making CPUs Even Faster


Building a faster CPU is not easy


Must consider time it will take to design,
manufacture and test the processor


To create CPU for release in 36 months, it
must perform at least twice as fast as what
is currently available


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22

Moore’s Law


Over 40 years ago, Moore predicted that the
number of transistors on a processor would
double every 18 months


Prediction has been remarkably accurate


Manufacturers can increase CPU
performance in several ways


Pipelining to boost performance


Specialized, faster instructions


Using CPUs
with six processing paths

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23

Pipelining


Boosts CPU performance


CPU works on more than one stage or

instruction at a time

24

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Special Multimedia Instructions


New processors incorporate multimedia
instructions into the basic instruction set


Multimedia
-
specific instructions work to
accelerate video, speech, and image
processing in the CPU


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25

Multiple Processing Efforts


Quad
-

processor has four separate CPU
chips on one motherboard


Multi
-
core processing


Dual
-
core processors have two separate
parallel processing paths


Six
-
core processors are appearing in high
-
performance home
-
based systems


Parallel processing uses multiple computers
to work on portion of same problem
simultaneously

26

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All rights reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, without the prior written
permission of the publisher. Printed in the United States of America.

Copyright ©
2013
Pearson Education, Inc.


Publishing as Prentice Hall