Requirement Analysis

What is Requirement?

Requirements describe the system’s behavior. Every software development process starts with the requirements collection. The customer has some notation of what the system will do. We collect the customer needs for a software system and prepare the requirements documents according to the customer needs. Requirements document will give an understanding of the system, we can say a blue print of the system. A requirement is a feature of the system or a description of what the system is capable of doing in order to fulfill the system’s purpose.

Requirements depend upon the project; they differ from project to project. Mainly we are using two types of requirements, functional and nonfunctional requirements. Functional requirements describe an interaction between the system and its environment. For example, calculating total marks of student in all subjects, gives the grade and rank. Nonfunctional requirements describe a restriction of the system that limits our choices for constructing a solution to the problem. For example hardware and man power resources etc...

Requirements Volatility .

Requirements volatility often results in significant growth in requirements size from the time of initial requirements specification to final requirements of the system development. Requirements volatility is an important risk in software project success, which can occur in multiple points during the software development process. These changes take place while the requirements are elicited, analyzed and validated and after the system has gone into service, simply through the software development lifecycle.

Requirements Volatility Causes Because.

1.    Internal Factors

•  Not capturing requirements from all relevant stake holders
•  Not using right requirement capturing technique depending on the context
•  Not capturing all relevant details
•  Not having measures such as check-list to ensure completeness of requirements captured
•  Not having measures to ensure clarity

2.    External Factors

•     Market driven
•         Need to be handled and managed

Types of Requirements.

There are mainly four types of requirements. They are conscious, unconscious, undreamed and none functional requirements.

Ø   Conscious Requirements:

Conscious requirements are those that the stakeholders are particularly aware of.

Ø  Unconscious Requirements:

Unconscious requirements are those that the stakeholder knows the requirement so well that he thinks that it’s not worth mentioning.

Ø  Undreamed Requirements:

Undreamed requirements are those that the stakeholders do not ask for, either because he thinks they are not possible or because they are new ideas that have occurred to them.

Ø  Non Functional Requirements:

Non functional requirement basically talks about hardware and software requirement of an application. It also talks about application performance, number of normal and concurrent users, page response time. They address business risk. Non-functional requirements are properties the product/ project must have, such as the desired look and feel, usability, performance, cultural aspects, availability, reliability, maintainability, extensibility, security and so on. This section discusses the types of non-functional requirements, and shows you how to use the template, and other methods, to find the all-important qualitative requirements for your product/ project.