Advance Operating System (CS G623)

Agenda

• Course Overview• Distributed System Basics• Multiprocessor Systems (Basic

Architecture)• Motivation behind Distributed Systems• Distributed System Architecture Types• Distributed Operating System• DOS Issues

• Text Book“Advanced Concepts in

Operating Systems: Distributed, Database and Multiprocessor Operating

Systems”, Tata McGraw Hill, 2001.

By

M. Singhal & N. Shivaratri

• Reference Books R1: P. K. Sinha, “Distributed Operating

Systems” Pearson Education, 1998.R2: Andrew S Tanenbaum and Martin Steen,

“Distributed Systems : Principles and Paradigms” ISBN: 978-81-203-3498-4

R3: Distributed Systems-Concepts and Design by G. Coulouris, AW

Plan of StudyS.No TOPIC CHAPTER

REF (Text)

No of Lectures

1.        

Overview of Advanced O.S: Design approaches, Motivation, Types of Advanced OS.

Ch 1 2

2.        

Architecture: Motivation, Issues, Communication Networks, Communication Primitives.

Ch 4 2

3.        

Theoretical Foundations: Limitations, Lamport’s logical clock, vector clock, causal ordering, global state, Cuts.

Ch 5 3

4.        

Distributed Mutual Exclusion: Lamport, Recart-agrawala, and Maekawa’s algorithms; Suzuki-kasami broadcast algorithm, and Raymond’s tree based algorithm .

Ch 6 4

5.        

Distributed Deadlock Detection: Resource Vs. Communication deadlock, Strategies to handle deadlock, Ho-Ramamoorthy, Path-Pushing, Edge-Chasing, Diffusion Computation-based algorithms.

Ch 7 4

6.        

Agreement Protocols: System model, Classification of agreement problems, Solutions to Byzantine agreement problems.

Ch 8 4

Plan of StudyS.No TOPIC CHAPTER REF

(Text)No of

Lectures

7.        

Distributed File Systems: Mechanisms for building DFSs, Design Issues, Sun DFS, and Sprite DFS.

Ch 9 4

8.        

Distributed Scheduling: Issues in Load Distribution, Components of a load distribution algorithm, Load Distribution Algorithms, V-system, Sprite, and Condor.

Ch 11 4

9.        

Distributed Shared Memory: Algorithms for implementing DSMs, Memory Coherence, and Coherence Protocols, IVY.

Ch 10 4

10. Recovery: Classification of failures, Synchronous and Asynchronous Checkpointing and Recovery.

Ch 12 3

11. Fault Tolerance: Commit Protocols, Voting Protocols, Failure Resilient Processes.

Ch 13 3

12.     Protection and Security: Access Matrix Model, Implementation of access matrix, Unix, and Amoeba, Introduction to Data Security.

Ch 14 3

Distributed Systems

“ A Distributed System is a collection of independent computers that appears to its users as a single coherent system ” [Tanenbaum]

“ A Distributed System is - a system having several computers that do

not share a memory or a clock- Communication is via message passing- Each computer has its own OS+Memory

[Shivaratri & Singhal]

Multiprocessor System Architecture Types

• Tightly Coupled Systems

• Loosely Coupled Systems

Tightly Coupled Systems

• Systems with a single system wide memory• Parallel Processing System , SMMP (shared

memory multiprocessor systems)

CPU Shared memory

CPU CPU CPU

Interconnection hardware

Loosely Coupled System• Distributed Memory Systems (DMS)• Communication via Message Passing

CPU

Localmemory

CPU

Localmemory

CPU

Localmemory

CPU

Localmemory

Communication network

Motivation

• Resource Sharing

• Enhanced Performance

• Improved Reliability & Availability

• Modular expandability

Distributed System Architecture Types

• Minicomputer Model

• Workstation Model

• Workstation – Server Model

• Processor Pool Model

• Hybrid Model

Mini-computer

Mini-computer

Mini-computer Communication

network

Terminals

MINICOMPUTER MODEL

WORKSTATION MODEL

Workstation

Communicationnetwork

WorkstationWorkstation

WorkstationWorkstation

Workstation

Communicationnetwork

WorkstationWorkstation

WorkstationWorkstation

Mini-computerused asfileserver

Mini-computerused asdatabaseserver

Mini-computerused asprintserver

. . .Mini-computerused asfileserver

WORKSTATION SERVERMODEL

Fileserver

Runserver

Communicationnetwork

Pool of processors.

...

Terminals

Processor Pool Model

Hybrid Model

• Based upon workstation-server model but with additional pool of processors

• Processors in the pool can be allocated dynamically

• Gives guaranteed response time to interactive jobs

• More expensive to build

Distributed OS

“A distributed OS is one that looks to its users like an centralized OS but runs on multiple, independent CPUs. The key concept is transparency. In other words, the use of multiple processors should be invisible to the user. “

[Tanenbaum & Van Renesse]

Issues

• Global knowledge• Naming• Scalability• Compatibility• Process Synchronization• Resource Management• Security• Structuring