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Distributed Operating Systems (Unit 5) Bus Multiprocessor              States of Cache Block Switched Multiprocessor Ring Based Multiprocessor Consistency Models Strict Casual PRAM Weak Release Entry Page Based Distribution Replication Granularity Finding Owner Finding Copies Page Replacement

  Distributed Operating Systems (Unit 4) Scheduling Normal time-sharing scheduling algorithms could lead to latency issues. When a processor tries to call another processor which will only get executed in the next time slice, it only increases the execution time. Co-Scheduling  - Uses a conceptual matrix in which each particular processor which is being called is in a particular row. This makes a round-robin scheduling algorithm with all processors running first the processor for a fixed time then, the next, and so on. Real-time Static Dynamic Fault Classifications Component Faults Transient - Can occur once and then disappear. Intermittent - Can occur, disappear, and reoccur later. Permanent - They stay till the component is repaired. System Failures - Processor Faults Fail Silent - Just stops upon fault and does not respond. Byzantine - Continues to run and gives malicious or wrong output. Synchronous - Responds to a message within known finite bound if working. Asynchronous Redundan

Distributed Operating Systems (Unit 3) Synchronize 2 Clocks Physical Time Services Broadcast Based - Server time is the main. It is broadcast and other systems follow this time. Simple Approach Berkeley Algorithm Request Driven Clock Synchronization Algorithms Mean-time - The clocks are set to the mean-time of the initial representation of the clocks. Centralized Algorithms Cristian's Berkeley Decentralized Algorithms Averaging - Network Time Protocol Lamport Timestamps Multiple External Time Sources Mutual Exclusion Algorithms Centralized Distributed Token Ring Election Algorithm Bully Algorithm Recogniser of no coordinator starts election. A message is sent to all higher numbers. No response makes them the coordinator. Ring Algorithm The process which recognizes failure starts a stack of numbers and tells the next. The next process which encounters this acknowledges by adding its number and passing. Properties of Transactions Atomic - Indivisible Consistent - No violation of basi