cosc1078 introduction to information technology lecture 16 processes

Lecture 16: Processes Intro to IT

COSC1078 Introduction to Information Technology

Lecture 16

ProcessesJames Harland

james.harland@rmit.edu.au

Lecture 15: Booting Intro to IT

Introduction

James Harland• Email: james.harland@rmit.edu.au• URL: www.cs.rmit.edu.au/~jah• Phone: 9925 2045• Office: 14.10.1 • Consultation: Mon 4.30-5.30, • Thu 11.30-12.30What colour is my office

door? Carpet? Chair?

Lecture 16: Processes Intro to IT

Introduction to IT1 Introduction 2 Images3 Audio4 Video WebLearnTest 1 5 Binary Representation Assignment 16 Data Storage7 Machine Processing8 Operating Systems WebLearn Test 29 Processes Assignment 210 Internet11 Internet Security   WebLearn Test 312 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 ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

11 ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

FF ROMRAM

Processor Memory Disk00

FF

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

FF ROMRAM

Processor Memory Disk00

FF

Lecture 16: Processes Intro to IT

Processes Executing in Context

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

``Thomas, you wouldn’t! Naughty!’’

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

``Thomas, you wouldn’t! Naughty!’’

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

BB

Lecture 16: Processes Intro to IT

``Thomas, you wouldn’t! Naughty!’’

Program Counter

InstructionRegister

BB ROMRAM

Processor Memory Disk00

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!