operating system, network & data...

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Fall 2009 - DE5

Operating System, Operating System, Network & Data Network & Data CommunicationCommunication

Dr. D. M. Akbar Hussain

Department of Electronic SystemsDE5 1

COURSE CONTENTS:

Fundamental concepts, how operating systems works, building blocks of an operating system, Process Concept, Memory and Scheduling.

TEXT BOOK: Operating System by William Stallings 6th Edition



By: William Stalling

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Fall 2009 - DE5



Course Web Site:

http://www.aue.auc.dk/~akbar/2010/operatingsystem-10.htm

Comments and opinion:

http://cs.aue.auc.dk/mailman/listinfo/de5-os



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Fall 2009 - DE5

Operating System, Network & Data Operating System, Network & Data Communication CourseCommunication Course

Objectives:

•Learning the basic Conceptual Picture of an Operating System. Introduction tovarious blocks and their functionalities in a computer system. Discussion of variousproblems and their solutions.

•Understanding Process Concept: Creation, Termination, States, Control andSwitching.

•Learning Concurrency, Mutual Exclusion and Synchronization, Semaphores. Dekker'sAlgorithm for Mutual Exclusion.



•What is Memory Management: Relocation, Protection, Sharing, Logical and PhysicalOrganization. Memory Partitioning. Paging and Segmentation, Virtual MemoryManagement. Protection and Sharing. Fetch, Place and ReplaceMechanism. Windows, UNIX and Linux Memory Management.

Operating System, Network & Data Operating System, Network & Data Communication CourseCommunication Course

What we will achieve (Hopefully):

•Hopefully at the end of this course you will have a very clear physical•Hopefully at the end of this course, you will have a very clear physical manifestation of a Modern Operating System, Data Communication and Protocols for Communications.

•You will have a very good understanding of what a process is; from creation to termination, you will have a deeper understanding of memory management, concurrency, mutual exclusion, synchronization.

•Operating system is a huge software so by the end of this course you will have a



Operating system is a huge software so by the end of this course you will have a good understanding of response, user friendly and efficient operating system constraints.

EXAM ?

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Fall 2009 - DE5

We shall be Looking at the Operating System the right way

& with Open Eyes



Basically an operating system is a program which acts as a

Operating System

y p g y p gmediator between the user and the computer hardware.

The aim of an operating system is to provide an environment inwhich user can execute program (….).

Operating system is an essential part of almost every computersystem. It is very interesting to understand that how thecomponents of the operating system have evolved as naturalsolutions to problems over the years


Department of Electronic Systems

solutions to problems over the years.

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Fall 2009 - DE5

Other InterpretationsOther Interpretations

Resource ManagerResource Manager

Control program

Kernel



Objectives & Function of an Operating System

OS TotalOS Total

Characteristics of an Operating System

Desirable Features in an Operating System

Transformation of Operating System with Time



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Fall 2009 - DE5

We have to use our HeadWe have to use our Head

How ?How ?



Issues in Designing System Software

1. Synchronization

2. Mutual Exclusion

3. Non-determinate program operation



4. Deadlocks

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Fall 2009 - DE5

Protection & Security

Today security and protection needs are very different and important because of networking, advancement and time sharing systems.

Protection and security of various resources and data is still the choice of an organization and its needs.

Following are major areas relating to security and protection:

Access Control/AuthenticityI f ti Fl C t l/C fid ti lit



Information Flow Control/ConfidentialityData Integrity

Scheduling and Resource Management

Main task of o/s is to manage resources and in doing so a typical o/s must have the following qualities:

It should be fair in respect of the access.It should be able to distinguish between different class of tasks to be performed.It should maximize throughput, minimize response time and should be able to accommodate as many processes as possible.



p

It may appear the above 3 characteristics to be simple in words, but in general it requires lot of discipline and research to have an o/s as stated.

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Fall 2009 - DE5

Kernel Architecture

Kernel

Every thing is part of the Kernel:

Scheduling

File SystemScheduling

IP Communication

Monolithic Kernel

Micro-Kernel



Networking

Device Drivers

Memory Management

Address Space Partitioning

Every thing else is built as utilities

W2K/VistaW2K/Vista• Exploits the power of today’s 32-bit

microprocessors.

• Provides full multitasking in a single-user • Provides full multitasking in a single-user environment.

• Client/Server computing which is the main motivation of multi-tasking.

• Modular structure for flexibility.

E t i t f h d l tf



• Executes on a variety of hardware platforms.

• Supports application written for a variety of other operating system.

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Fall 2009 - DE5

CharacteristicsCharacteristics

Modified micro-kernel architecture

It is not a pure micro-kernel as typically defined Many system functions outside of the micro-kernel run in kernel mode



Any module can be removed, upgraded, or replaced without rewriting the entire system.

W2K/VistaW2K/Vista



Thread Scheduling, Process Switching, Exception, Interrupt handling and multi-processor synchronization

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Fall 2009 - DE5


NTDLL contains a number of kernel-mode functions that implement m ch of the f nctionalit of the Windo s APIimplement much of the functionality of the Windows API.

NTDLL does not handle any graphical components.

NTDLL is responsible for File I/O functions, threading and synchronization, timing, messages, it contains a lot of



y , g, g ,primitive kernel-mode code that performs most of the low-level tasks in Windows.


H d Ab t ti L (HAL) id i l ti f l tf ifi h d diffHardware Abstraction Layer (HAL) provides isolation for platform specific hardware differences.

Device drivers translate user I/O function calls into hardware specific device requests.

The kernel manages thread scheduling, process switching, exception and interrupt handling, and multiprocessor synchronization.

Unlike the rest of the Executive and the user level, the micro-kernel's own code does not run in threads. Hence, it is the only part of the operating system that is not preempt able or page-able.

Device drivers: Include both file system and hardware device drivers that translate user I/O function



Device drivers: Include both file system and hardware device drivers that translate user I/O function calls into specific hardware device I/O requests.

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Fall 2009 - DE5


• User Processes:Four basic types of user processes are supported by W2K:

1. Special system support processes: Include services not provided as part of the W2Koperating system, such as the logon process and the session manager.

2. Server processes: Other W2K services such as the event logger.

3. Environment subsystems: Expose the native W2K services to user applications andthus provide an OS environment, or personality. The supported subsystems areWin32, POSIX, and OS/2. Each environment subsystem includes dynamic link



libraries (DLLs) that convert the user application calls to W2K calls.

4. User applications: Can be one of five types: Win32, POSIX, OS/2, Windows 3.1, orMSDOS.



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Fall 2009 - DE5





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Fall 2009 - DE5

LINUXLINUX



LINUX does not use a microkernel approachLINUX does not use a microkernel approachIt is a Collection of loadable modules

◦ Dynamic linking◦ Stackable modules



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Fall 2009 - DE5

Linux Kernel ModulesLinux Kernel Modules



Summary of Management Summary of Management Features of an OSFeatures of an OS

PROCESS MANAGEMENT

MAIN MEMORY MANAGEMENT

SECONDRY MEMORY MANAGEMENT

I/O SYSTEM MANAGEMENT

FILE MANAGEMENT


Department of Electronic Systems

PROTECTION MANAGEMENT

NETWORKING SYSTEM MANAGEMENT

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Fall 2009 - DE5

One Could Also Say Os is a Machine Controlling ThingsOne Could Also Say Os is a Machine Controlling ThingsBut do you Think it is a Machine Like ThisBut do you Think it is a Machine Like ThisHappy Thinking ?Happy Thinking ?



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