Distributed Systems
Last updated
Last updated
Systems where software and hardware components, placed in a network, communicate and coordinate their actions by passing messages.
DS Coulouris
A set of independent computers that are presented to the user as a single integrated system. DS Tanembaum
Collection of autonomous computing elements.
Global clocks.
Membership management.
Open.
Close.
Single coerent system.
Available services:
Communication (eg. RPC).
Transactions.
Service composition.
Reliability.
Support of resource sharing.
Transparent distribution (application and user)
Openness.
Scalability.
| Transparancy | Description |
|---|---|
Access | Hides the differences in data representation and in the method of access. |
Localization | Hides where an object is located |
Relocation | Hides the fact that an object can be moved to another location while in use. |
Migration | Hides the fact that an object can be moved to another location. |
Replication | Hides the fact that an object can be replicated |
Concurrency | Hides the fact that an object can be shared between concurrent users. |
Flaws | Hides the flaws in recoveries of an object. |
"Being open".
Using components that can be used, or integrated, into other systems.
Interoperability.
Composition.
Extensibility.
Size.
Geographic.
Administrative.
The Network is reliable
The Network is secure
The Network is homogenous
The topology is inmutable
Zero latency
Infinit bandwith
No cost of transport
There is a single administrator
