lecture 11: system fundamentals intro to it cosc1078 introduction to information technology lecture...
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Lecture 11: System Fundamentals Intro to IT
COSC1078 Introduction to Information Technology
Lecture 11
System FundamentalsJames Harland
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!