A distributed system is a collection of processing components that communicate with each other and appear to the external users as a single system.

Goals of Distributed Computing

• Resources accessibility
• Distribution transparency
• Openness
• Scalability

Resource Accessibility

Distributed computing, as the name suggests, facilitates access to resources geographically distributed inside and outside the enterprise

Distribution transparency

The actual location of resources used during processing is transparent to the user who sees one single system.

Levels of transparency: Access, Location, Migration, Replication, Concurrency, Failure

Openess

A distributed system is open if it is based on widely accepted standards. Examples: SOAP, WSDL, IIOP, UDDI, XML

Scalability

Scalability represents the capability of a distributed system to handle increasing amounts of work in a gracefull manner