Introduction Chapter 1 Agenda - Definition -Hardware concept -Software concept -The Client-Server model Definition of a Distributed System (1) A distributed system is: A collection of independent computers that appears to its users as a single coherent system.
A distributed system organized as middleware.Note that the middleware layer extends over multiple machines.
Different forms of transparency in a distributed system.
Examples of scalability limitations.
An example of dividing the DNS name space into zones.
Different basic organizations and memories in distributed computer systems
General interaction between a client and a server.
-Vertical distribution Model : where the tiers corresponded directly with the logical organization of the apps (The previous architectures)
-Horizontaldistribution Model: where the application layers are physically split up into logically equivalent part
-> This is how high-performance web services (e.g., Google, Amazon, E-bay..)