Introduction%20to%20Distributed%20Computing - PowerPoint PPT Presentation

About This Presentation



Lecture 6: Introduction to Distributed Computing Distribute Systems and Distributed Computing Contents Introduction of Distributed Systems Distributed Computation ... – PowerPoint PPT presentation

Number of Views:94
Avg rating:3.0/5.0
Slides: 15
Provided by: tns53
Learn more at:


Transcript and Presenter's Notes

Title: Introduction%20to%20Distributed%20Computing

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
  • Clock in Asynchronous Distributed Systems and
    Snapshot algorithms
  • Fault-Tolerant Algorithms

Construction of Distributed Systems
  • Units of A Distributed System
  • Units/Nodes (Computers, sensors, )
  • Network
  • Software

What Is Distribute Systems?
  • There is no unique definition for distributed
    systems. Similar terms are
  • Networked system
  • parallel systems
  • Concurrent systems
  • Decentralized systems

Enslows Definition Distributed System
Distributed hardware Distributed control
Distributed data
Distributed Hardware
Physically shared/distributed memory and
logically shared/distributed memory
Logically shared Logically distributed
Physically shared Common memory Simulated message passing
Physically distributed Distributed shared memory message passing
  • Distributed System Software
  • Cooperating the actions of units (computers,
    sensors, )
  • Supporting system resources (hard ware and
    software) sharing.
  • Supporting data sharing.

  • 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.

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 mans
    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,.)

Distributed Computational models
  • Processes never mind in which unit they are.
  • Communicating links communication channels

  • 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).

  • Communication Links
  • Bidirectional
  • Asynchronous
  • Infinite FIFO queue
  • Without fault (no massage losing, alteration)

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

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.

  • 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.
Write a Comment
User Comments (0)