Difference between centralized and distributed computing
Main basic differences are:
- distrib-systems have no global state
- no shared memory
- no shared variables
- distrib-systems have no shared time clock
- therefore order of events is difficult
- distrib-systems can have race conditions
- race conditions see http://en.wikipedia.org/wiki/Race_condition
So "computing" in a distrubuted environment is very difficult. Do you have concret question about programing models or whatever?
Centralized
A system with centralized multiprocessor parallel architecture.In the late 1980 s Centralized systems have been progressively replaced by distributed systems.
characteristics of centralized system
- Non autonomous components
- usually homogeneous technology
- Multiple users share the same resources at all time
- single point of control
- single point of failure
Distributed
set of tightly coupled programs executing on one or more computers which are interconnected through a network and coordinating their actions. These programs know about one another and carry out tasks that none could carry out in isolation
characteristics of distributed system
- autonomous components
- Mostly build using heterogeneous technology
- System components may be used exclusively
- Concurrent processes can execute
- Multiple point of failure
Requirement of distributed system
- Scalability- possibility of adding new hosts
- openness- easily extended and modified
- Heterogeneity-supports various H/W S/w platforms
- Resource sharing- H/w, S/W and data
- fault tolerance- ability to function correctly even if faults occur
Centralized: all calculations are done on one particular computer (system). Example: you have a dedicated server for calculating data.
Distributed: the calculation is distributed to multiple computers. Example: when you have a large amount of data then you can divide it and send each part to particular computers which will make the calculations for their part.