Operating Systems

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Oct 26, 2013 (3 years and 7 months ago)

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Lecture 14: Operating Systems

Intro to IT


COSC1078 Introduction to
Information Technology


Lecture 14


Operating Systems


James Harland

james.harland@rmit.edu.au

Lecture 14: Operating Systems

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
-
12.30

What
colour

is my office
door? Carpet? Chair
?

Lecture 14: Operating Systems

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 14: Operating Systems

Intro to IT


Overview


Questions?



Assignments 1 & 2



Operating Systems



Questions?


Lecture
14: Operating Systems

Intro to IT


Assignments 1& 2

Assignment 1


Currently being marked


Will have marks out later this week


Assignment 2


Specification has been published


Must

be done in
groups of 2 or 3


Can change groups from Assignment 1 (if you wish)


Must

have a
blog on Blackboard

Lecture
14: Operating Systems

SE Fundamentals

Questions?

How did you spend 6
-
8 hours on this course
last week?

This week?

Lecture 14: Operating Systems

Intro to IT


Operating Systems

operating
system

kernel

device driver

open source

real time

virtual machine

desktop
publishing

Lecture 14: Operating Systems

Intro to IT


Operating Systems

Operating

system

Lecture 14: Operating Systems

Intro to IT


Operating Systems


Manage hardware and software resources


Memory allocation


Prioritising requests and processes


Controlling input and output devices


Managing network access


Managing file systems


Dealing with multiple users




Lecture 14: Operating Systems

Intro to IT


Operating Systems

HARDWARE

HARDWARE

USER

Lecture 14: Operating Systems

Intro to IT


Operating Systems

Lecture 143: Operating Systems

Intro to IT


Operating Systems


Concurrent execution of processes on a single CPU


Memory management

Registers, caches, RAM, hard disk, plug
-
ins, ...

Movement of data between these


File systems


Networking


Printers, scanners, LAN, wireless, Internet, ...

Lecture 14: Operating Systems

Intro to IT


Operating Systems


Graphical User Interface (GUI)


Colors
, data, cursors, ...


Device drivers

Code specialised for particular hardware device
(DVD writer, printer, monitor, ...)


Controls access to these


Security


Passwords, file sharing, protocols, ...

Lecture 14: Operating Systems

Intro to IT


Operating Systems


Desktop (Windows,
MacOS
, Linux, ... )


Windows around
85
% of market


Server systems

Google

“back end”, server farms, ...

Windows Server or Unix


Specialist systems


Supercomputers, call centres, real
-
time systems,
PDA systems, ...

Lecture 13: Operating Systems

Intro to IT


Operating Systems


Lecture 14: Operating Systems

Intro to IT


Linux


Open source


Developed in
1991

by
Linus

Torvalds


Written in C


RedHat
, Mandrake,


SUSE,
Ubuntu
, ...


RedHat

7.1
has

30
million+ lines of code


Lecture 14: Operating Systems

Intro to IT


Windows


Add
-
on to MS
-
DOS

in
1985


Most popular OS


Known security

issues


Windows XP

40
million lines of code


Vista released
2007


Windows
7
(now!)

Lecture 14: Operating Systems

Intro to IT


MacOS


Only on Apples


Introduced by Apple


in
1984


GUI from the start


Based on Unix


Graphics features


Mac OS X Leopard

Lecture
14:
Operating Systems

Intro to IT


Where to begin?

How do you start an operating system?

Boot it! (or bootstrap)




Turn on power (

)




Machine loads bootstrap program from
ROM (non
-
volatile memory)




Bootstrap program loads OS




OS takes over

Lecture
14:
Operating Systems

Intro to IT


Initial State When Turned On

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
14:
Operating Systems

Intro to IT


Load Bootstrap Program

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
146
: Operating Systems

Intro to IT


Bootstrap program loads OS

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
14:
Operating Systems

Intro to IT


Bootstrap program loads OS

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
14:
Operating Systems

Intro to IT


Bootstrap program has loaded OS

Program
Counter

Instruction

Register

AA

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

AA

Lecture
14:
Operating Systems

Intro to IT


OS takes over execution

Program
Counter

Instruction

Register

AA

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

AA

Lecture
14:
Operating Systems

Intro to IT


Starting Up Operating Systems

Program
Counter

Instruction

Register

AA

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

AA

Lecture
14
:
Operating Systems

Intro to IT


Starting Up Operating Systems

Program
Counter

Instruction

Register

AA

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

AA

Lecture
14:
Operating Systems

Intro to IT


Starting Up Operating Systems

Program
Counter

Instruction

Register

AA

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

AA

Lecture 16: Operating Systems

Intro to IT


Multiple boot scenario …

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture 16: Operating Systems

Intro to IT


Multiple boot scenario …

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture 16: Operating Systems

Intro to IT


Multiple boot scenario …

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
14:
Operating Systems

Intro to IT


Multiple boot scenario …

Program
Counter

Instruction

Register

00

ROM

RAM

Processor

Memory

Disk

Bootstrap

Program

00

Lecture
14:
Operating Systems

Intro to IT


OS Software Classification

Software

System

Application

Utility

Kernel

Operating System

Shell

Lecture 16: Operating Systems

Intro to IT


Processes

Lecture
14:
Operating Systems

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
14
:
Operating Systems

Intro to IT


Processes Executing in Context

Program
Counter

Instruction

Register

CC

ROM

RAM

Processor

Memory

Disk

00

CC

Lecture
14
:
Operating Systems

Intro to IT


Processes Executing in Context

Program
Counter

Instruction

Register

DD

ROM

RAM

Processor

Memory

Disk

00

CC

DD

Lecture
14:
Operating Systems

Intro to IT


Processes Switching

Ready

Ready

Waiting

Scheduler

maintains
process table

Lecture
14:
Operating Systems

Intro to IT


Processes Switching

Lecture
14:
Operating Systems

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
14:
Operating Systems

Intro to IT


Processes Executing in Context

Program
Counter

Instruction

Register

BB

ROM

RAM

Processor

Memory

Disk

00

BB

Lecture
14:
Operating Systems

Intro to IT


Processes Executing in Context

Program
Counter

Instruction

Register

11



ROM

RAM

Processor

Memory

Disk

00

BB

Lecture
14:
Operating Systems

Intro to IT


Processes Executing in Context

Program
Counter

Instruction

Register

FF

ROM

RAM

Processor

Memory

Disk

00

FF

Lecture
146
: Operating Systems

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
15
: Operating Systems


Intro to IT


Conclusion



Work on Assignment 2



Web Quizzes and Web Test 2



Finish reading book!