Lecture 11: System Fundamentals Intro to IT

COSC1078 Introduction to Information Technology

Lecture 11

System FundamentalsJames Harland

james.harland@rmit.edu.au

Lecture 11: Computer Fundamentals

Intro to IT

Introduction to IT

1-4 Introduction, Images, Audio, Video

5 Computer Fundamentals Assignment 1, WebLearn Test 1

6 Computer Fundamentals

Tuesday April 13th, Wednesday April 14th

7 Computer Fundamentals /Review/Catch Up

8 Operating Systems WebLearn Test 2

9 Operating Systems Assignment 2

10 Internet

11 Internet Security   WebLearn Test 3

12 Future of IT Assignment 3, Peer and Self Assessment

Lecture 11: Computer Fundamentals

Intro to IT

Overview

Questions?

WebTest 1

Review/Catch up

Computer Fundamentals

Questions?

Lecture 11: Computer Fundamentals

Intro to IT

Web Test 1

There was a buggy question on the test

Not everyone would have done it

Best effort on Test 1 or Test 1A will count

Buggy question will be ignored

Lecture 11: Computer Fundamentals

Intro to IT

Review /Catch Up

Next week!

Let me know via email of any requests for material

Otherwise I will choose what to cover …

Requests in by this week

Lecture 11: Computer Fundamentals

Intro to IT

What do computers do? Compute!

Input/Output

Processing

Memory

Lecture 3: System Internals Intro to IT

Moore’s Law

“Processor speed doubles about every 18 months”

-- Gordon Moore, Intel co-founder, 1965

Intended for period 1965-1975

Held true ever since 1965!

Must end sometime …

Lecture 3: System Internals Intro to IT

Moore’s Law

Lecture 3: System Internals Intro to IT

Moore’s Law

Lecture 3: System Internals Intro to IT

Memory

Memory differs in performance and cost

Processor is typically much faster than memory

Lecture 3: System Internals Intro to IT

Memory

Arranged as a hierarchy of cache

Level 1Level 2

Level 3

Main Memory

Lecture 11: Computer Fundamentals

Intro to IT

Processing

ALU

CPUBUS

REGISTERS

MEMORY

Lecture 11: Computer Fundamentals

Intro to IT

Machine Instructions

1. Move first value from memory into register 12. Move second value from memory into

register 23. If register 2 is zero, go to Step 64. Divide register 1 by register 2 & store result

in register 35. Store register 3 value in memory6. Stop

“Divide two numbers”

Lecture 11: Computer Fundamentals

Intro to IT

Machine Instructions

1. LOAD register 1 from memory2. LOAD register 2 from memory3. JUMP to Step 6 if register 2 is zero4. Divide register 1 by register 2 and store

result in register 35. STORE register 3 value in memory6. Stop

Lecture 11: Computer Fundamentals

Intro to IT

Instructions in Binary?01010100001010101010100110100010101001101001010010100011100010101010100101111001001010…

LOAD register 1LOAD register 2JUMP ….STORE ….

1010110010110011000100100011001100111111

MEMORY

Lecture 11: Computer Fundamentals

Intro to IT

One Scheme

16-bit operation codes (simple example)

Operation Code(4 bits)

Operand (12 bits)

Represent as 4 Hexadecimal numbers (0-9,A-F)Each instruction is two bytes long

Lecture 11: Computer Fundamentals

Intro to IT

One Scheme

156C LOAD register 5 from memory 6C166D LOAD register 6 from memory 6D5056 ADD register 5 & 6 & store in register 0306E STORE register 0 to memory 6EC000 HALT....(up to 216 = 65,536 different instructions)

Lecture 11: Computer Fundamentals

Intro to IT

Fetch Decode Execute

FETCH

EXECUTE DECODE

Machinecycle

Lecture 11: Computer Fundamentals

Intro to IT

Two special registers

Instruction register: holds current instructionProgram counter: address of next instruction

Fetch: Put instruction specified by program counter into instruction registerIncrement program counter by two

Decode: Work out what to do

Execute: Perform the instruction

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A0Address Contents

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A0FETCH

156C

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A2FETCH

156C

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A2DECODE

156C

6C 2B

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A2

EXEC

156C

6C 2B

2B5

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A2 FETCH

166D

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A4 FETCH

166D

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A4 DECODE

166D

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A4 EXEC

166D

6D FF

FF6

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

A6 FETCH

5056

Lecture 11: Computer Fundamentals

Intro to IT

Processing

A0 15A1 6CA2 16A3 6DA4 50A5 56A6 30A7 C0A8 C0A9 00

Program Counter

InstructionRegister

…

Lecture 11: Computer Fundamentals

Intro to IT

Processing

Program Counter

InstructionRegister

EXEC

B258

B4

Lecture 11: Computer Fundamentals

Intro to IT

Processing

Program Counter

InstructionRegister

EXEC

B258

58

Lecture 11: Computer Fundamentals

Intro to IT

Processing

Jump instructions change program counter

Can load any memory address into program counter (!!!)

Often use pipelining for efficiency Fetch next instruction while executing Processor doesn’t wait for fetch to complete

Can do more than one instruction …

Lecture 11: Computer Fundamentals

Intro to IT

Conclusion

Assignment 2 specified sometime this week

Finish reading book!