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

FY04: Introduction to the use of computers jennifer george Acknowledgement  Jeremy Gow jennifer george 1

Last week’s lecture  Measuring digital data  Bits  Bytes  Kilobytes  Megabytes  ...  SI and Binary units jennifer george More Last week  Binary files  Hexadecimal  Text files  Character sets  Text encodings  ASCII, Unicode jennifer george 2

This week  What a computer really is  The Processor  Transistors  Processor architecture  Moore’s Law jennifer george 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 jennifer george 3

Storage and processing  So far we have looked at storing data  But computers also process data  Processing changes data  Computers are data processors jennifer george Input and Output I/O devices es  Input  Output  Keyboard  Screen  Mouse  Speakers  Scanner  Printer  Network card  Network card  Storage  Storage jennifer george 4

Motherboard jennifer george 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) jennifer george 5

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 jennifer george ‘Computer Speed & Capacity’  A computer’s speed is defined by:  The type of processor  Amount of RAM  ....on the motherboard jennifer george 6

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 jennifer george 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 jennifer george 7

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 jennifer george 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 jennifer george 8

jennifer george 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) jennifer george 9

Integrated Circuits (Microc ochip hips, , Silicon on 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 jennifer george Computer Architecture  CPU on an integrated circuit  Control Unit co-ordinates activities  Clock regulates activity at a set speed (GHz) jennifer george 10

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 jennifer george 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 jennifer george 11

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 jennifer george Coprocessors  Help main processor do special tasks  e.g. graphics, sound, encryption  Designed to be faster at this one task  Optional extra jennifer george 12

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 jennifer george Putting more on the chip  Technology allows more & more circuitry on 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. jennifer george 13

Neural networks  Digital computers process structured data sequentially  Neural networks process unstructured information simultaneously  Digital computers are faster and accurate in numeric computation jennifer george 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 jennifer george 14

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 jennifer george Moore’s Law Gordon on 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 on a single wafer. jennifer george 15

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 jennifer george Moore’s Law Intel l chips jennifer george 16

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 jennifer george 17