What do we mean by distributed systems?

Authors Avatar

CAS546- Distributed SystemsLecture 1 - What are Distributed Systems?

What do we mean by distributed systems?

  • Distributed Operating Systems?
  • Distributed Applications?
  • Distributed Databases?
  • Networked Systems?
    -Wide Area?
    -Local Area?

These are all loosely coupled distributed systems and are what we are interested in. Tightly coupled systems such as array processors i.e. those which generally share memory are of little interest on this course. The World Wide Web is very loosely coupled distributed computing environment, based on the transmission and reception of messages. Bank Automatic Teller Machines (ATM) are components of another distributed system. The Sun Operating System, Solaris is another which offers distributed file storage and process execution.

Join now!

What are the characteristics of Distributed Systems?

These characteristics are taken from the book Distributed Systems - Concepts and Design:

  • Networks - they are all networked one way or another
  • Communication - often message passing
  • Resource sharing - files, data, processors
  • Openness - UNIX, Java, CORBA
  • Concurrency - components of the system may execute simultaneously
  • Scalability - increasing the size of a system should have no effect other than an increase in performance or capacity.
  • High Availability and fault tolerance - acheived through the natural redundancy  of multiple replicated components.
  • Transparency ...

This is a preview of the whole essay