Its the designing of a s/w s/m.
The s/m is divided into a set of functional units named modules,that can be composed into a large form of application.
A module represents a set of related concerns.
It can include a collection of related components such as features,views or business logic and pieces of infrastructures such as logging and authenticating users.
Modules are independent one another but can communicate in loosely coupled fashion.
Consider an online banking s/m, user can access variety of features such as transfer money btw accounts, paying bills and updating their personal information in a single user interface.However, behind these scenes each of these functions are discrete modules.
When a program is modularized its tasks are divided into several modules based on some characteristics.
Modules are set of instructions put together to achieve some task.
There are measures by which the quality and interaction of designs can be measured.These measures are called Coupling and Cohesion.

	Created by shanid m about 8 years ago

DEGREE SOFTWARE ENGG Note on MODULARITY, created by shanid m on 08/10/2016.