1 / 14

Lecture 6: Introduction to Distributed Computing

Lecture 6: Introduction to Distributed Computing. Distribute Systems and Distributed Computing. Wei Chen, Professor Tennessee State University. Contents Introduction of Distributed Systems Distributed Computation Models Synchronous Network Algorithms Asynchronous Network Algorithms

Download Presentation

Lecture 6: Introduction to Distributed Computing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lecture 6: Introduction to Distributed Computing

  2. Distribute Systems and Distributed Computing Wei Chen, Professor Tennessee State University • Contents • Introduction of Distributed Systems • Distributed Computation Models • Synchronous Network Algorithms • Asynchronous Network Algorithms • Clock in Asynchronous Distributed Systems and Snapshot algorithms • Fault-Tolerant Algorithms

  3. network Construction of Distributed Systems • Units of A Distributed System: • Units/Nodes (Computers, sensors, … ) • Network • Software

  4. What Is Distribute Systems? • There is no unique definition for distributed systems. Similar terms are • Networked system • parallel systems • Concurrent systems • Decentralized systems Enslow’s Definition Distributed System = Distributed hardware + Distributed control + Distributed data

  5. Physically shared memory Physically distributed memory processor processor processor processor processor processor memory memory memory Network Network memory Distributed Hardware Physically shared/distributed memory and logically shared/distributed memory

  6. Distributed System Software • Cooperating the actions of units (computers, sensors, …) • Supporting system resources (hard ware and software) sharing. • Supporting data sharing.

  7. Distributed Control • Master/Slave (fixed/dynamic) • Multi control points (homogenous/heterogeneous) • Distributed Data • Copies: Processors hold data copies. • Divided data: Data are divided and distributed to processors.

  8. Features of Distributed Systems • Resource sharing: hardware, software, data • Openness: openness of main interface of the system, scalability of the current system • Concurrency: concurrent execution of the processes, high performance, nice rate of price and performance (PC cluster = poor man’s supercomputer ) • Fault tolerance: ability to tolerate the fault of system units, availability( using potential redundancy to overcome the system fault). • Transparency: a distributed system can be looked as one computer (access transparency, position transparency, parallel transparency,….)

  9. Communication link Computer process Distributed Computational models • Processes: never mind in which unit they are. • Communicating links: communication channels

  10. Process • Generalized RAM (Random Access Machine) • CPU with program • Infinite memory • Message changeable with adjacent processes • Each process has a distinct ID. • Without fault (it will be considered in the model with fault).

  11. Receiving in order of A,B,C Sending in order of A,B,C • Communication Links • Bidirectional • Asynchronous • Infinite FIFO queue • Without fault (no massage losing, alteration)

  12. Synchronism • Running speed of each process • Transmission delay • Speed of the local clock in each process: constant upper and lower bounds

  13. Real clock Local clock Real time Local Clock of Synchronous Distribute Systems p(t): the value of the local clock of process p at moment t Typical synchronous distributed model: Round Model • Processes execute each round synchronously • Each round consists of message receiving, computation, and • message sending • Processes accept the message sent from the previous round.

  14. Complete asynchronous model • No assumption for the speed of processes. • No assumption for the transmission delay of communication links. • No assumption for the speed of local clocks.

More Related