THE SOFTWARE REQUIREMENTS DOCUMENT

THE SOFTWARE REQUIREMENTS DOCUMENT:
The software requirements document/specification (or SRS) is an official statement of what the system developers should implement. It should include both the user requirements for a system and a detailed specification of the system requirements. Sometimes, the user and system requirements are integrated into a single description. In other cases, the user requirements are defined in an introduction to the system requirements specification. If there are a large number of requirements, the detailed system requirements may be presented in a separate document.

Persons in SRS:

The requirements document has a diverse set of users, ranging from the senior management of the organization that is paying for the system to the engineers responsible for developing the software. The diversity of possible users means that the requirements document has to be a compromise between communicating the requirements to customers, defining the requirements in precise detail for developers and testers, and including information about possible system evolution. Information on anticipated changes can help system designers avoid restrictive design decisions and help system maintenance engineers who have to adapt the system to new requirements.
The level of detail that you should include in a requirements document depends on the type of system that is being developed and the development process used. Critical systems need to have detailed requirements because safety and security have to be analyzed in detail. When the system is to be developed by a separate company (e.g., through outsourcing), the system specifications need to be detailed and precise. If an in-house, iterative development process is used, the requirements document can be much less detailed and any ambiguities can be resolved during development of the system.