Difference between loosely coupled and tightly coupled system

What is a loosely coupled system?

It is a concept of system design and computing where loosely coupled system is one in which every individual component has no knowledge of the definitions of other components.

In another meaning loosely coupled architecture or system means changes in one module / section that affect the other components and every module is somewhat independent of each other.

In a loosely coupled system, hardware and software may interact but they are not dependent on each other.

 

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What is a tightly coupled system?

It is a concept of system design and computing where every hardware and software components that are linked together in such manner that each component is dependent upon each other.

For example, in a tightly coupled system when a dependent class contains a pointer directly to a concrete class which provides the behavior of the object.

Tightly coupled architecture promotes interdependent applications and code. 

Tightly coupled architecture is fragile as the minor issue in one segment can bring the whole system down.

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Another example of tightly coupled system

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Difference:

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	Tightly coupled system	Loosely coupled system
1	It has shared memory concept	It has distributed memory concept
2	Contention is high in tightly coupled	Contention is low in loosely coupled
3	It has low scalability	It has high scalability
4	It has low delay	It has high delay
5	Data rate in tightly coupled system is high	Data rate in loosely coupled system is low
6	Cost of tightly coupled system is high	Cost of loosely coupled system is low
7	It has dynamic interconnection network	It has static interconnection network
8	It operates on Single Operating System	It operates on Multiple Operating System
9	In tightly coupled system cache memory assign according to the need of processing	In loosely coupled system, each process have its own cache memory
10	Throughput is high in tightly coupled	Throughput is low in loosely coupled
11	Security is high in tightly coupled	Security is low in loosely coupled
12	Low space in this architecture	High space in this architecture
13	Power consumption is lower than loosely coupled system	Power consumption is higher than tightly coupled system
14	Not reusable in the case of flexibility	Reusable in the case of flexibility
15	Ex., Zeon processor	Ex., Beowulf cluster