Acknowledgement Jeremy Gow jennifer george 1 Last weeks lecture - - PDF document

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FY04: Introduction to the use of computers

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Acknowledgement

 Jeremy Gow

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Last week’s lecture

 Measuring digital data  Bits  Bytes  Kilobytes  Megabytes  ...  SI and Binary units

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More Last week

 Binary files  Hexadecimal  Text files  Character sets  Text encodings  ASCII, Unicode

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This week

 What a computer really is  The Processor  Transistors  Processor architecture  Moore’s Law

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The story so far

 Computers deal with binary data  Data storage have grown bigger over 50

years

 Data is stored in files  Files are accessed through filesystems  The same file could be on several

filesystems

 Text files = binary files + encoding  Binary data may be viewed as hexadecimal

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Storage and processing

 So far we have looked at storing data  But computers also process data  Processing changes data  Computers are data processors

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Input and Output

I/O devices es

 Input  Keyboard  Mouse  Scanner  Network card  Storage  Output  Screen  Speakers  Printer  Network card  Storage

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Motherboard

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Describing Processors

 A computer might be described as a  64-bit (Word)  2.3 GHz (Processor Speed)  3072 MB (Memory Capacity)  PC (Operating System/Platform)

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The Processor

 Central Processing Unit (CPU)  AKA The Processor  Performs processing (computation)  Accesses resources (I/O devices)  Modern CPU built of millions of

transistors

 Clock regulates processing (speed in

GHz)

 e.g. Intel Core Duo: 151m transistors,

2.33 GHz

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‘Computer Speed & Capacity’

 A computer’s speed is defined by:  The type of processor  Amount of RAM  ....on the motherboard

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Who makes the (micro)processors?

 Intel  Motorola  Advanced Micro Devices (AMD)  Cyrix  IBM

* Within the context of a PC, the terms processors and microprocessors are used interchangeably

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Microprocessors

 Smaller than a postage stamp  Found in wristwatches, sewing

machines, CD players, elevators and anything electronic

 This is a computer on a chip  Chip refers to a self integrated circuit

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Known Microprocessors

 1971: Intel 4004, 4044  First microprocessor  4-bit  1981 – 1984: Intel 8088, 8085  First 8-bit processor  Into the 90’s: Intel 286 (Intel 80286),

386, 386

 1990’s-2000’s: Intel Pentium , Pentium

Pro, Pentium II & III, Celeron, Itanium

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The Processor

 The nucleus or the brain of any

computer

 The CPU(Processor) has two

fundamental sections:

 Control Unit  Arithmetic and Logic Unit  These work together with the RAM

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Transistors

 Electronic component  Applying voltage to one terminal affects

current flowing between other two

 Acts as a switch  Can represent 0 or 1  (more with logic gates

next week)

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Integrated Circuits

(Microc

• chip

hips, , Silicon

• n Chips)

 Millions of electronic components, e.g.

Transistors

 Components very close (millions per mm!)  Small area (mm!)  ‘Printed’ onto silicon using light  Low power (less heat)  Low cost  High performance

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Computer Architecture

 CPU on an integrated circuit  Control Unit co-ordinates activities  Clock regulates activity at a set

speed (GHz)

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Arithmetic-Logic Unit

 Circuitary that performs operations on

data

 Integer arithmetic operations (addition,

subtraction, multiplication, division)

 Logic operations (next week)  Reads data from input registers  Control unit tells it which operation  Writes data to output registers

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Register Unit

 Registers store data being worked on

by CPU

 Example: adding two numbers  Move numbers from memory to input

registers

 ALU writes answer to output register  New data moved from register to memory

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Moving data around

 Bus moves data between CPU to

main memory

 Takes time to transfer data  Cache stores recently used data in

CPU

 Faster than retrieval from main memory  Avoids having to always use bus  Much smaller than main memory

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Coprocessors

 Help main processor do special tasks  e.g. graphics, sound, encryption  Designed to be faster at this one task  Optional extra

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Parallel Processing

Core 2 Duo

 The concept of using multiple

processors in the same computer system

 One main processor examines the

problem and allocates portions to be solved simultaneously

 The individual pieces are then

reassembled in the main processor

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Putting more on the chip

 Technology allows more & more circuitry

• n chip

 System on a chip: CPU + main

memory

 Much faster bus transfer  Multi-core: more than one CPU on

chip

 Can increase performance  Often have shared cache  Dual-core, quad-core etc.

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Neural networks

 Digital computers process structured

data sequentially

 Neural networks process unstructured

information simultaneously

 Digital computers are faster and

accurate in numeric computation

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Neural Networks

 Neural networks are used where the

computer is required to function as a human brain

 Playing chess  Improving automobile engine efficiency  Enabling improved vision technology  Planning crop and rotation strategies  Forecasting financial market fluctuations

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Example: New 13” Macbook

 Intel Core 2 Duo  Clock speed: 2.0 GHz or 2.4 GHz  Two CPUs on chip  3MB cache  1066MHz bus  2GB main memory

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Moore’s Law

Gordon

• n Moore (1965)

 The complexity for minimum component

costs has increased at a rate of roughly a factor of two per year... Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built

• n a single wafer.

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Moore’s Law

 The number of transistors that can be

cheaply placed on an integrated circuit doubles every two years

 Exponential growth in transistors-per-

chip

 Related to increase in chip power  Roughly true since 1965  Result of many technological advances  Will approach physical limits at some

point

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Moore’s Law

Intel l chips

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Summary

 Processor (CPU) made of millions of

transistors

 Integrated circuits allow small powerful

CPUs

 Control Unit, ALU, Registers, Bus, Cache  Co- and multi-core processors  Moore’s law: transistors on chip double in 2

yrs

 Reading: Brookshear 2.1, White 5 & 6

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