lecture7:Distributed system architecture

The architecture include:
The division of responsibilities between system components.
The placement of the components on computers in the network.

Client-server model:

Most important and most widely distributed system architecture.
Client and server roles are assigned and changeable.
Servers may in turn be clients of other servers.
Services may be implemented as several interacting processes in different host computers to provide a service to client processes:
Servers partition the set of objects on which the service is based and distribute them among themselves (e.g. Web data and web servers)
Provides a shared cache of web resources for client machines at a site or across several sites.
Increase availability and performance of a service by reducing load on the WAN and web servers.
All processes play similar roles without destination as a client or a server.
Interacting cooperatively to perform a distributed activity.
Communications pattern will depend on application requirements.

1.Distributed Computing Systems
Many distributed systems are configured for High-Performance Computing
Example : Cluster Computing: Essentially a group of high-end systems connected through a LAN.

2.Distributed Information Systems
The vast amount of distributed systems in use today are forms of traditional information systems, that now integrate legacy systems. Example: Transaction processing systems.

3.Distributed Pervasive Systems
There is a next-generation of distributed systems emerging in which the nodes are small, mobile, and often embedded as part of a larger system