Introduction to AOS course

Van Hoang Nguyen

Mail: [email protected]

Department of Computer Science – FITA – HUA

Advanced Operating System Course ---------------------------------- Fall 2012

Dept. of Computer Science – FITA – HUA

Advanced Operating System – Fall 2012

Van Hoang Nguyen http://en.wikipedia.org/wiki/EDVAC


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Registers

Stack

R

S

R

S

R

S


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batch, interactive, real-time


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throughput, turnaround time, CPU

utilization

response time, proportionality

meeting deadlines, predictability


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› Shortest Remaining Time Next


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› Shortest Process Next

› Guaranteed Scheduling

› Lottery

› Fair share


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Strict alternation

Peterson’s solution

TSL/XCHG

Semaphores

Mutexes

› Barrier


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memory hierarchy


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Base and Limit Register

Swap

Virtual Memory


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long-term information storage


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File A File B File C

File

block

0

File

block

1

File

block

2

File

block

3


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File A

0 1 2 3 4 5 6 7

6 7 -1 2


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File’s Name Attributes




File’s Name

File’s Name

File’s Name

File’s Name


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Van Hoang Nguyen Sourced by: Machine learning overview – Ho T.B


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(diversity of mobile devices)


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Lecture Reference

Introduction [3] Chapter 1 - 13

Parallel and Distributed [1]. Chapter 8

Real-Time [1]. Chapter 7 and [2]

WebOS

Kernel Architecture

Big Storage

Protection and Security [1]. Chapter 9


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Regular attention 10%

Mid 30%

Final 60%

Total 100%


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while (turn!=0) /*loop*/;

critical_region();

turn=1;

noncritical_region();

while (turn!=1) /*loop*/;

critical_region();

turn=0;

noncritical_region();


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void enter_region(int process)

{

int other;

other = 1-process;

interested[process]=1;

turn=process;

while (turn==process

&& interested[other]==1);

}

void leave_region(int process)

{

interested[process]=0;

}


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enter_region:

TSL REGISTER,LOCK

CMP REGISTER,#0

JNE enter_region

RET

leave_region

MOVE LOCK,#0

RET

enter_region:

MOVE REGISTER,#1

XCHG REGISTER,LOCK

CMP REGISTER,#0

JNE enter_region

RET

leave_region

MOVE LOCK,#0

RET


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void producer(){

int item;

while(true){

item=produce_item();

down(&empty);

down(&mutex);

insert_item(item);

up(&mutex);

up(&full);

}

}

void consumer(){

int item;

while(true){

item=produce_item();

down(&full);

down(&mutex);

item=remove_item();

up(&mutex);

up(&empty);

consume_item(item);

}

}


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mutex_lock:

TSL REGISTER,MUTEX

CMP REGISTER,#0

JZE ok

CALL thread_yield

JMP mutex_lock

ok: RET

mutex_unlock:

MOVE MUTEX,#0

RET


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a simplest version of dynamic relocation


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not enough to hold all process in physical memory

OS

A

B

C

OS

B

C

OS

D

B

C

OS

D

C

OS

D

C

A


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==> some issues › Fixed size while data segment can grow

› allocate an extra memory

› arrange stack and heap segment

› Big process can not run

› Fragmentation problem

› External Fragmentation

› Internal Fragmentation

› memory compact ==> waste CPU time OS

Code

Data

Stack

Room for

grow


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==> some issues › How to manage free memory

› bitmaps: unit size, difficult to allocate

› free lists

› How to allocate

› first fit

› next fit

› best fit

› worst fit

› quick fit


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Page

Page

frame

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Introduction to AOS course

Technology

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