Windows OS Architecture in Summery

transcript

Presented By :

Arachchi N.C.R. (148205J)

Dilruk G.A. (148209B)

Thursday, April 23, 2015 1

Index …

Microsoft Windows Overview

History

Single-User Multitasking

Architecture

Operating System Organization

User-Mode Processes

Client/Server Model

Threads and SMP

Windows Objects

History

MS-DOS/PC-DOS 1.0- 1981 Developed for first IBM PC

Consist of 4000 lines of assembly source code

Ran in 8KB

Used Intel 8086 microprocessor

DOS 2.0- 1983 Released with IBM PC XT

Support Hard Disk and provided hierarchical directories

Memory resident portion up to 24KB

History cont.…

MS-DOS 3.0/Windows 1.0- 1984 Introduced with IBM AT PC

Support for new Keyboard and Hard Disk peripherals

Memory requirement 36KB

MS-DOS 3.1- 1984 Support for Networking of PC’s

MS-DOS 3.3- 1987 Support for IBM PS/2

Memory resident portion grown minimum of 46KB

History cont.…

Windows 3.0- 1990 Introduced GUI

Support for new Keyboard and Hard Disk peripherals

Memory requirement 36KB

MS-DOS 3.1- 1984 Support for Networking of PC’s

MS-DOS 3.3- 1987 Support for IBM PS/2

Memory resident portion grown minimum of 46KB

History cont.…

Windows 95- 1995 Introduced Taskbar, Start menu, Explorer file manager

Windows 98- 1998 Usage of WDM (Windows Driver Model)

USB Support

Windows 2000- 2000 Plug and Play improvements

History cont.…

Windows XP-2001 Windows Vista-

Windows 7-2009 Windows 8-2012Thursday, April 23, 2015 7

Single-User Multitasking

The operating system is designed mainly with a single user in

mind, but it can deal with many applications running at the same

What happens if a user wishes to create a drawing and paste it

into a word processing document without multitasking??

Potentials

Increased speed and memory capacity of microprocessors.

Growth of client/server computing

1. Open the drawing program.

2. Create the drawing and save it in a file or on a temporary

clipboard.

3. Close the drawing program.

4. Open the word processing program.

5. Insert the drawing in the correct location

Architecture

Set of routines that

give a program

access to the

hardware

resources

HAL makes each

machine hardware

look same to the

kernel

Delivers the

support needed for

symmetric multi

processing (SMP)

Architecture cont.…

Kernel

Contains most

used and

fundamental

component.

Manages

• Thread

scheduling

• Process

switching

• Exception and

interrupt

handling

• Multiprocessor

synchronization

Only part that is

not preemptive and

pageable

Architecture cont....

Device Drivers

Include file system

and hardware

drivers

Translate user I/O

function calls to

hardware specific

requests.

Windowing and

graphics system

Handles GUI

functions such as

window component

management,

drawing, etc..

Executive

Contains the base

OS services such

• Memory mgmt.

• Process and

thread mgmt.

• Security

• I/O

• Inter process

communication

I/O Manager

Implements all the

Windows I/O APIs

Enforces security

and naming for

devices and file

systems

File System Cache

Improves the

performance by

keeping recently

referenced disk

data and holding

updates for short

Object Manager

Creates, manages

and deletes

executive objects,

processes, threads

synchronization

objects

Create object

handlers which

consist of access

control information

and a pointer to

the object

Plug and Play

manager

Determines which

drivers are

required to support

a particular device

and load them

Power Manager

Coordinates the

power among

devices and

reduce the power

consumption by

putting the

processor to sleep

on idle

Security reference

monitor

Manages the

access and the

audit logs through

out the system

Virtual Memory

Manager

Maps the virtual

address in the

process’s address

space to physical

addresses

Process / Thread

Manager

Manage processes

and threads

Configuration

manager

Responsible

manage the

system registry

which contains the

system and user

settings

Local procedure

Manage the

communication

between executive

subsystems

User Mode processes

System Support

Processes

Include the

services not

provided as part of

the kernel

• Logon process

• Session

manager

• Local Security

authentication

server

Service Processes

Other windows

services such as

event logger,

spooler

Architecture cont....User Mode processes

User Applications

Can be a

• Win32

• Posix

• OS/2

• Windows 3.1

• MS-DOS

application

User Mode processes

Environment

Subsystems

Expose the

windows services

to user

applications.

Responsible to

convert user

application calls to

windows calls

User Mode processes

Client/Server Model

Each environment and a execute service subsystem is

implemented as one or more processes

Each process waits for a request from a client for one of its

services

Client requests a service by sending a message

Server performs the requested operation and returns the

result

Advantages

Simplifies the Executive

Improves Reliability

Provides suitable base for distributed computing

Threads and SMP

OS routines can run on any available processor

Windows supports multiple threads execution within a single

process

Server processes may use multiple threads to process

request from more than one client simultaneously

Windows provides mechanisms for sharing data resources

between processes and flexible interprocess communication

capabilities

Windows Objects

The approach of object-oriented design facilitates the sharing

of resources and data among processes and the protection of

resources from unauthorized access

Encapsulation

Object class and instance

Inheritance

Polymorphism

Object may be either named or unnamed

Eg. of objects managed by kernel (two categories)

1. Control objetcs

2. Dispatcher objects

Continue …

Windows Threads

Process & Thread Objects

Multithreading

Thread States

Symmetric Multiprocessing

Windows Memory Management

Virtual Address Map

Paging

Windows Scheduling

Process & Thread Priorities

Multiprocessor Scheduling

Windows Process & Thread

Objects

Windows process are implemented as objects

Executable process may contain one or more threads

Each process is assigned a security access token

Windows Process & Thread

Objects

Multithreading

Threads in different process can execute

concurrently

Moreover, multiple threads within the same

process execute simultaneously in different

processors

Threads within same process can exchange

information through their common address space

Ex : In server application each client can have a

separate thread to serviceThursday, April 23, 2015 34

Thread States

Symmetric Multiprocessing

Threads of any process can run on any processor

Windows microkernel assigns a ready thread to

the next available processor in case of absence

of affinity restrictions

Two Affinity policies

Soft affinity

Hard affinity

Windows Memory Management

Each process on 32-bit Microsoft Windows has its

own virtual address space that enables

addressing up to 4 gigabytes of memory

Memory manager controls memory allocation and

how paging is performed

Only some parts of the program and data that are

currently in active use need to be held in physical

RAM and other parts are in a swap file

Virtual Address Space

Virtual address space for a

process is the set of virtual

memory addresses that

process can use

The virtual address space

for 32-bit Windows is 4

gigabytes (GB) in size and

divided into two partitions:

one for use by the process

and the other reserved for

use by the system

Windows Paging

Page sizes are ranging from 4Kb to 64Kb for different

platforms

Two-level hierarchical memory map

Page directory table

• Page directory entries (PDEs) point to page table

• One page directory table per process

• Location in page directory register

Page table

• Page table entries (PTEs) point to page frames

TLB (translation look aside buffer) accelerates address

translation

Windows use local page replacement

Less recently used pages out algorithm

Virtual Address Translation

Windows Scheduling

Mainly consider responsiveness in highly

interactive environment.

Preemptive scheduling

Priority levels

Round-robin scheduling Algorithms

Two priority classes, real time and variable

Each consist of 16 levels

Threads needed immediate attention is in the real

time class, those have precedence over others

Lower priority thread will preemptive when higher

one is ready

Real-time class priorities are fixed while variable

class can up or downThursday, April 23, 2015 42

Multiprocessor Scheduling

In a multiprocessor system with N processors

The (N -1) highest priority thread are always active

And running on (N -1) extra processors

The Remaining lower priority threads share the

single remaining processor

Windows OS Architecture in Summery

Engineering