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Lecture 16: Processes Intro to IT
COSC1078 Introduction to Information Technology
Lecture 16
ProcessesJames Harland
Lecture 15: Booting Intro to IT
Introduction
James Harland• Email: [email protected]• URL: www.cs.rmit.edu.au/~jah• Phone: 9925 2045• Office: 14.10.1 • Consultation: Mon 4.30-5.30, • Thu 11.30-12.30
What colour is my office door? Carpet? Chair?
Lecture 16: Processes Intro to IT
Introduction to IT
1 Introduction
2 Images
3 Audio
4 Video WebLearnTest 1
5 Binary Representation Assignment 1
6 Data Storage
7 Machine Processing
8 Operating Systems WebLearn Test 2
9 Processes Assignment 2
10 Internet
11 Internet Security WebLearn Test 3
12 Future of IT Assignment 3, Peer and Self Assessment
Lecture 16: Processes Intro to IT
Overview
Questions?
Assignment 2
Assignment 3
Processes
Questions?
Lecture 16: Processes Intro to IT
Processes
Lecture 16: Processes Intro to IT
Processes
A program is a static set of instructions
A processes is the execution of a program, which changes state over time.
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
CC ROM
RAM
Processor Memory Disk
00
CC
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
DD ROM
RAM
Processor Memory Disk
00
CC
DD
Lecture 16: Processes Intro to IT
Processes Switching
Ready
Ready
Waiting
Scheduler maintains process table
Lecture 16: Processes Intro to IT
Processes Switching
Lecture 16: Processes Intro to IT
Interrupts
Signals to the CPU Often generated by timing circuits CPU reacts by jumping to appropriate memory location
Dispatcher selects a ready process resets timing circuit starts process
CPUs often designed to switch process states efficiently
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
11 ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
FF ROM
RAM
Processor Memory Disk
00
FF
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
FF ROM
RAM
Processor Memory Disk
00
FF
Lecture 16: Processes Intro to IT
Processes Executing in Context
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
``Thomas, you wouldn’t! Naughty!’’
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
``Thomas, you wouldn’t! Naughty!’’
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
``Thomas, you wouldn’t! Naughty!’’
Program Counter
InstructionRegister
BB ROM
RAM
Processor Memory Disk
00
BB
Lecture 16: Processes Intro to IT
Software
`Programs should be able to do anything!’ (???)
Programs should be able to do anything reasonable
What is reasonable?
Not changing OS, not deleting other processes from memory, not playing with other people’s things, …
Lecture 16: Processes Intro to IT
Interrupts
Provide mechanism to switch processes
CPU doesn’t have to wait for I/O transfers
Switching leads to faster throughput
`Save document’ means CPU does something else while the save takes place
Lecture 16: Processes Intro to IT
Conclusion
Work on Assignment 2 (and 3?)
Web Quizzes and Web Test 2
Finish reading book!
