Case Study of Distributed System

Definition of Distributed System

A distributed system is a network that consists of autonomous computers that are connected using a distribution middleware.

They help in sharing different resources and capabilities to provide users with a single and integrated coherent network.

Block Diagram of Distributed System

Examples of Distributed Systems

1. Intranets

A single authority protected access – a firewall.

Services:

  • Infrastructure services
  • File service
  • Name service
  • Application services

2. Resource Sharing

Resource Sharing and the Web Hardware resources (reducen costs) Data resources (shared usage of information) Service resources search engines computer-supportedncooperative working Service vs. server.

Goals Of Distributed System

  1. Making resources accessible
  2. Distribution transparency
  3. Opennessn Scalability
  4. Security
  5. System design requirements

1. Making Resources Accessible

  • Naming Access control
  • Security
  • Availability
  • Performance
  • Mutual exclusion of users

2. Transparency

Distribution in users viewpoint: a single unified system.

3. Concurrency

  • Several simultaneous users.
  • Integrity of data
  • Mutual exclusion
  • Synchronization

4. Openness

  • Making the network easier to configure and modify.
  • Openness facilitates
    • Interoperability,
    • Portability,
    • Extensibility,
    • Adaptivity

5. Security

Security is a big challenge in a distributed environment, especially when using public networks.

6. Scalability

Distributed systems should be scalable with respect to geography, administration or size.

7. Reliability

Compared to a single system, a distributed system should be highly capable of being secure, consistent and have a high capability of masking errors.