Updated April 4, 2023
Introduction to Software Requirement Specification
The requirement is nothing but a condition needed by the user to solve a problem or achieve an objective. It is the first step in the development of a system. Software requirements specification lists out all the requirements stated by the user inconsistent manner. Great software can be created only from a great specification. Systems and software these days are so complex that to get on with the design before knowing what you are going to build is foolish and risky. Software documentation is also called a software requirements specification.
Software Requirement Specification Components
Software requirements specification includes the following details
- Functionality: It addresses what software supposed to do
- Performance: It addresses the speed, response timings, availability, recovery time, software function, etc.
- External interface: It addresses how does the software interact with people, the system’s hardware, other hardware, and other software.
- Attributes: It addresses the portability, correctness, security, reliability, maintainability, etc.
- Design constraints imposed on an implementation: It addresses the required standards in effect, implementation language, policies for database Integrity, resource limits, operating environments, etc.
Characteristics of Software Requirement Specification
Characteristics of software requirements specification are as follows:
- Correct: This is like motherhood and apple pie. Of course, you want the specification to be correct. No one worries about a Specification that they know is incorrect. Correct and ever correcting, i.e. keeping the specification up to date when you find things that are not correct.
- Unambiguous: A requirement specification is unambiguous if and only if every requirement stated therein has only one interpretation. Spending time on this area before releasing the requirements specification can be a waste of time. But as you find ambiguities, fix them first.
- Complete: A simple judge of this is that it should be all that the software designer needs to create the software.
- Consistent: The software requirements specification should be consistent within itself and consistent with its reference documents. If you call an input Start and Stop in one place, don’t call it Start or Stop in another.
- Verifiable: Don’t put in requirements like – it should provide the user with a fast response, or the system should never crash. Instead, provide a quantitative requirement like – every keystroke should provide a user response within 1000 milliseconds.
- Ranked for importance: Very often, a new system has requirements that are really marketing wish lists. Some may not be achievable. It is useful to provide this information in the requirements specification.
- Modifiable: Having the same requirements in more than one place may not be wrong but tends to make the document not maintainable.
- Traceable: Often, this is not important in a non-politicized environment. However, in most organizations, it is sometimes useful to connect the requirements in the requirements specification to a higher-level document.
- Software requirements specification form the basis for agreement between customers and development organization on what the software product is expected to do. A complete description of the software’s function that is expected is specified in the requirements specification. This will help end-users to verify whether the software meets the specified needs or not. If not, then how the software must be manipulated to meet the requirements.
- Software requirements specification reduces development efforts. Preparing the requirement specification forces various stakeholders to think thoroughly of all their requirements before the design begins, thus reducing the efforts needed for redesigning, recoding, and retesting. Careful inspection of the requirements specified can reveal the left-outs and inconsistency early in the development. Thus it becomes easier to correct these problems.
- Software requirements specification provides a baseline for verification and validation. The software development team can develop its verification and validation plans or test plans much more effectively from a well-prepared requirements specification document. As it provides a baseline against which requirement confirmation can be measured.
- It forms a base for cost estimation and project scheduling. As a complete description of the product to be developed is specified in the software requirements specification, it helps in estimating the project costs and can be used to obtain approval from the customer for the decided price estimates.
- It facilitates the transfer of new software to new environments. Software requirements specification makes it easier to transfer the software product to new clients or new hardware machines. So that developers feel easier to transfer the software to new clients and customers feel easier to transfer the software to other systems of their organization.
- It serves as a basis for software improvement. Requirements specification describes the product features and not the process of project development; therefore, it serves as a basis for enhancement by allowing the developers to do any later modification if required on the finished product. But then requirements specification needs to be altered in that case, I.e. it forms a base FO continuous product evaluation.
This is a guide to Software Requirement Specification. Here we have discussed the basics of the software requirements specification with its benefits and compliance. Here we have also discussed how it will help in the development life cycle. You may also have a look at the following articles to learn more –