System Requirements Specification

In this topic, you will learn about, System Requirements Specification (SRS).

SRS is a set of complete and stated properties along with the of the system that the software must satisfy. A well-designed software requirement specification establishes a boundary and solution of a system to develop.

The SRS should specify only the external behaviour of the system and not to the internal details.

We can also think of SRS as an agreement between the client and the developer that what is to be developed and what problems are to be solved.

Characteristics of SRS:

  1. Unambiguously: all the requirements must be stated unambiguously that is every requirement stated should have only one interpretation.
  2. Complete: the definition should include all the function and constraints intended by the system user.
  3. Realistic: the requirements should be realistic and achievable with current technology.
  4. Verifiable and consistent: the requirements should be verifiable and they are to be verified by the system tester during testing. It makes sure that no requirements conflict with any other requirements.
  5. Modifiable: the structure and style of the SRS should be such that any necessary change to the requirements can be made easily, completely and consistently.
  6. Traceable: it should be traceable to the other requirements and related documents. The origin of each requirement must be clear.
  7. Useable: it must be useable during the operation and maintenance of the system.

Structure of a typical SRS Documents:

  1. Introduction.
  2. An informative description of the system.
  3. A functional description of the system.
  4. Test and validation criteria.
  5. Dictionary.
  6. Bibliography.
  7. Appendix.
See also  Stages of system development life cycle


  1. System reference and business objective of the documents are implemented
  2. Goals and objectives of the system describing in the context of the computer-based system are documented.
  3. The scope of the document.

An informative description of the system:

  1. Structure representation.
  2. Description of sub-systems and system interface.
  3. A detailed description of the problem of the problem that the software must be solved.
  4. Details of information flow, content and its structure are documented.

A functional description of the system:

  1. The functional description of every module is defined.
  2. Restriction and limits to every module are defined.
  3. A diagram to represent the overall structure and all the basic structure of the software graphically.

Test and validation criteria: here we document the expected software response under various conditions.
Glossary (Dictionary): Definition of all technical or software specific terms used in the documents.
Bibliography: List and reference of all documents that relate to the system (software).
Appendix: supplementary information of the system is documented.

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