Distributed Operating System

ByMuhammad Adeel Rajput

Scientist/Instector

System Architecture

Hardware

Operating System

Application Software

User / Machine

Hardware

• Can be• Input Device• Processing Device• Memory / Storage Device• Output Device

Operating System• Consist of:

– Kernel• Is heart of any OS. It is responsible of Managing Hardware and Software

resources efficiently.– Command Interpreter

• Is used to provide communication between hardware and software / user through software (i.e. it translate human written program / instruction into instruction set that is understandable by the hardware).

– Device Drivers• These are the software which are written for specific hardware supported by

the OS. When new hardware driver is installed , it becomes part of OS.– Utility Software

• These are small programs helps OS to perform different tasks i.e. formatting disk, tuning memory etc.

User / Machine

• User of system can be machine or human both can directly or indirectly (through application software) communicate with the operating system.

Application Software• Theses are software which are used to take input from user /

machine and provide output after processing by the hardware.

• For instance a CD ROM reads data(i.e. Pictures) from optical disk and showed onto screen. Or play a movie etc.

• Application Software can not run without operating system.• Common examples are

– Word Processing Software– Spread Sheets Software– Graphics Designing Software – Database Software etc

Types of Operating System

• Standalone– Is a type of OS which is not connected to any other computer

in the network hence there is no concept of resource sharing.• Networked– Is a type of OS in which two or more computers / peripherals

are connected in a network for resource sharing (i.e. peripherals, Disk space)

• Distributed– Is a type of Network OS in which not only devices are

connected with each other but also shares (memory & processor) with each other.

Stand Alone OS Architecture

Network OS Architecture

Processor

Network OS Services

kernel

Machine A Machine B Machine C

kernel kernel

Local Memory

Processor

Network OS Services

Local Memory

Processor

Network OS Services

Local Memory

Kernel

Processor

Structure of Parallel Computing

Shared Memory

Kernel

Machine A Machine B Machine C

Processor

Kernel

Processor

Structure of DOS

Distributed Applications

Distributed Operating system services

Machine A Machine B Machine C

kernel kernel kernel

Shared Memory & Processor

Distributed Applications

Distributed applications (distributed apps) are applications or software that runs on multiple computers within a network at the same time and can be stored on servers or with cloud computing. Unlike traditional applications that run on a single system, distributed applications run on multiple systems simultaneously for a single task or job.

Software that executes on two or more computers in a network. In a client-server environment, distributed applications have two parts: (1) the 'front end' that requires minimal computer resources and runs on the client computer(s), and (2) the 'back end' that requires large amounts of data crunching power and/or specialized hardware, and runs on a suitably equipped server computer.

Parallel Processing

• It is type of distributed computing in which a process is divided into lightweight processes called threads.

• All threads run concurrently on different computing machines with sharing memory.

Parallel Computing

• It is type of distributed computing in which a process is divided into lightweight processes called threads.

• All threads run concurrently on different computing machines without sharing memory.

Distributed Memory System

• In distributed memory system each system has its own memory commutations are done locally however if remote data is required then it can be done through communication with one or more computers.

Shared Memory System

• In Shared memory system multiple processors shares single memory. Processor dos not needs to know where the data is being saved. But whenever there are performance penalties and race conditions then processor has to track data location to avoid such conditions.

Inter-process communication (IPC)

• Is a mechanism that provides communication between two or more processes – With-in single system memory.– With-in a network having shared or separate

memory.– Between two processes reside on different

networks.

IPC (Through Kernel) System A

Processor

Kernel

Process 1(Browser)

Process 2(DNS)

Process 3(Email)

Process 4 (FTP)

Process 5 (Ping)

www.yahoo.com what is IP ?

IPC (Through Kernel) System A

Processor

Kernel

Process 1(Browser)

Process 2(DNS)

Process 3(Email)

Process 4 (FTP)

Process 5 (Ping)

www.yahoo.com what is IP ?

IPC (Through Kernel) System A

Processor

Kernel

Process 1(Browser)

Processing …

Process 3(Email)

Process 4 (FTP)

Process 5 (Ping)

IP is 202.154.11.91

IPC (Through Kernel) System A

Processor

Kernel

Process 1(Browser)

Process 2(DNS)

Process 3(Email)

Process 4 (FTP)

Process 5 (Ping)

Local Procedure Call

• Is a method in which a procedure calls another procedure which is reside on another system within/outside of the Network.

Processor

Kernel

Process 1(Browser)

Process 2(DNS)

Remote Procedure Call

• Is a method in which a procedure calls another procedure which is reside within the system.

Processor

Kernel

Process 1(Browser)

P 2(Local DNS)

Processor

Kernel

Process 1(Browser)

P 2(Local DNS)

LAN/WAN LAN/WAN