Subject: Distributed Operating System

1. Subject: Distributed Operating System Topic: Limitation Of Distributed Operating System Prepared By: Prof. ImranAhmad. Anjuman College Of Engineering & Technology Department Of Computer Science & Engineering.

2. Syllabus • Fundamentals: Introduction, Models and Features, Concept of Distributed Operating system, Issues in Design of a Distributed Operating System. Foundations of Distributed System: Limitations of Distributed Systems, Lamport’s logical clocks, Vector clocks, Causal ordering of messages, Global state recording, Cuts of a Distributed Computation, Termination Detection. • Distributed Mutual Exclusion: Requirement of Mutual Exclusion Algorithm, Non Token Based Algorithms: Lamport’s Algorithm, Ricard-Agrawala Algorithm, Maekawa’s Algorithm, Token Based Algorithms: Suzuki-Kasami’s Broadcast Algorithm, Singhal’s Heuristic Algorithm, Raymond’s Tree-Based Algorithm, Comparative Performance Analysis. • Distributed Deadlock Detection: Introduction, Deadlock Handling strategies in Distributed System, Centralized and Distributed Deadlock Detection AlgorithmsAgreement protocols: Introduction, System Model, Classification of Agreement Problms, Solutions to the Byzantine Agreement Problem. • Distributed File system: Introduction to Distributed File System, Architecture, and Mechanism for Building Distributed File System, Distributed Shared Memory: General Architecture of DSM systems, Algorithm for Implementing DSM, Memory coherence and Coherence Protocols. • Distributed Scheduling: Introduction, Issues in Load Distributing, Components of a Load Distributing Algorithm, Load Distributing Algorithms: Sender-Initiated Algorithm, Receiver-Intiated algorithm, Symmetrically Initiated Algorithm, Adaptive Algorithm, Requirements for Load Distributing Task Migration, Issues in Task Migration. • Failure Recovery: Recovery in concurrent systems, Consistent set of Checkpoints, Synchronous check pointing and Recovery, Asynchronous check pointing and Recovery, Fault Tolerance: Introduction, Commit Protocols, Static Voting Protocol, Dynamic Voting Protocol.

3. CourseOutcome • Explain the basic fundamentals of Distributed OS . like models, features, concept ,design issues and fundamentals of distributed system. • Analyze the mutual exclusion • Demonstrate the deadlock detection and agreement protocol of distributed OS. • Describe the distributed file system and distributed shared memory. • Explain various Distributed scheduling algorithm and load distributed algorithm. • Identify fault tolerance and failure recovery.

4. Limitation of Distributed system. • Defination: • Distributed system is a collection of autonomous computer that are interconnected via some communication networks or Internet.

5. Limitation of Distributed system. Cont... There are certain limitations of distributed systems that leave impact on the diesign of distributed systems Following are limitations of Distributed System : • No global clock. • No shared Memory.

6. No global clock. • Possible solutions • Common clock for all distributed computers • Disadvantage: Unpredictable and variable transmission delays make it impractical • Synchronized clocks, one for each computer • Disadvantage: Each clock will drift at a different rate, making it impractical • Conclusion • No system-wide physical common (global) clock can be implemented

7. No shared Memory. • No single process can have complete,uptodate state of entire distributed system i.e.global state • Any operating system or process cannot know accurately the current state of all processes in the distributed system

8. No shared Memory. Cont… • An operating system or process can only know • The current state of all processes on the local system • The state of remote operating systems and processes that is received by messages • These messages represent the state in the past • Implementation of mutual exclusion and avoidance of deadlock and starvation become much more complicated

9. Thank you.