1. Requirements Specification
Section Five
Version: 1.0
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Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

2. What
What is SRS?
The Software Requirements Specification (SRS) captures the software requirements for the complete system, or a portion of that system.
The SRS focuses on the collection and organization of all requirements surrounding your project.
The SRS package controls the evolution of the system throughout the development phase of the project, as new features are added or modified to the Vision document, they are elaborated within the SRS Package.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

3. What
What is SRS?
The SRS Package is not a frozen tome, it is an active, living artifact.
It serves as a basis of communication between all parties - i.e., between the developers themselves, and between the developers and the external groups (users and other stakeholders) with whom they must communicate.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

4. What
SRS Standards
Several recommended guides and standards exist to help define the structure of requirements documentation. Include
IEEE P1233/D3
IEEE Std. 1233
IEEE Std
ISO/IEC
IEEE Std Concept of Operations
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

5. SRS Outline (Based on RUP)
What
SRS Outline (Based on RUP)
Introduction         
Overall Description    
Specific Requirements
  Functionality     
  Usability     
  Reliability     
  Performance     
  Supportability     
  Design Constraints     
  Online User Documentation and Help System Requirements     
  Purchased Components     
  Interfaces     
  Licensing Requirements     
  Legal, Copyright and Other Notices     
   Applicable Standards     
Supporting Information    
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

6. Who
Who Uses SRS?
The following people use the Software Requirements Specification:
The system analyst creates and maintains the Vision and Supplementary Specifications, which serves as input to the SRS and are the communication medium between the system analyst, the customer, and other developers.
The requirements specifier creates and maintains the individual use case and other components of the SRS package,
Designers use the SRS Package as a reference when defining responsibilities, operations, and attributes on classes, and when adjusting classes to the implementation environment.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

7. Who
Who Uses SRS? (con.)
Implementers refer to the SRS Package for input when implementing classes.
The Project Manager refers to the SRS Package for input when planning iterations.
Testers use the SRS Package to verify system compliance.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

8. What
Vision
Defines the stakeholders view of the product to be developed, specified in terms of the stakeholders key needs and features.
The Vision provides a high-level, sometimes contractual, basis for the more detailed technical requirements.
It captures the "essence" of the envisaged solution in the form of high-level requirements and design constraints that give the reader an overview of the system to be developed from a behavioral requirements perspective.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

9. Supplementary Specification
What
Supplementary Specification
The Supplementary Specification artifact capture system requirements that are not readily captured in behavioral requirements artifacts such as use-case specifications.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

10. How
From Vision to SRS
The SRS Package is obviously related to the Vision document.
Vision document serves as the input to the SRS. But the two artifacts serve different needs and are written by different authors.
In SRS the focus of the document moves from the broad statement of user needs, goals and objectives, target markets and features of the system to the details of how these features are going to be implemented in the solution.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

11. Requirements identification
How
It is essential for requirements management that every requirement should have a unique identification
The most common approach is requirements numbering based on chapter/section in the requirements document.
Problems with this are:
Numbers cannot be unambiguously assigned until the document is complete
Assigning chapter/section numbers is an implicit classification of the requirement. This can mislead readers of the document into thinking that the most important relationships are with requirements in the same section
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

12. Requirements identification techniques
How
Dynamic renumbering
Some word processing systems allow for automatic renumbering of paragraphs and the inclusion of cross-references.
Database record identification
When a requirement is identified it is entered in a requirements database and a database record identifier is assigned. This database identifier is used in all subsequent references to the requirement
Symbolic identification
Giving each requirement a symbolic name. For example, EFF-1, EFF-2, EFF-3 for system efficiency requirements
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

13. Storing requirements
How
Requirements have to be stored in such a way that they can be accessed easily and related to other system requirements
Possible storage techniques are
In one or more word processor files - requirements are stored in the requirements document
In a specially designed requirements database
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

14. Word processor documents
How
Advantages
Requirements are all stored in the same place
Requirements may be accessed by anyone with the right word processor
It is easy to produce the final requirements document
Disadvantages
Requirements dependencies must be externally maintained
Search facilities are limited
Not possible to link requirements with proposed requirements changes
Not possible to have version control on individual requirements
No automated navigation from one requirement to another
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

15. Requirements database
How
Each requirement is represented as one or more database entities
Database query language is used to access requirements
Advantages
Good query and navigation facilities
Support for change and version management
Disadvantages
Readers may not have the software/skills to access the requirements database
The link between the database and the requirements document must be maintained
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

16. Object classes for requirements DB
What
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

17. Requirements DB - choice factors
What
The statement of requirements
If there is a need to store more than just simple text, a database with multimedia capabilities may have to be used.
The number of requirements
Larger systems usually need a database which is designed to manage a very large volume of data running on a specialised database server.
Teamwork, team distribution and computer support
If the requirements are developed by a distributed team of people, perhaps from different organisations, you need a database which provides for remote, multi-site access.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

18. Database choice factors
What
CASE tool use
The database should be the same as or compatible with CASE tool databases. However, this can be a problem with some CASE tools which use their own proprietary database
Existing database usage
If a database for software engineering support is already in use, this should be used for requirements management.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

19. A Sample Documentation Tool
What
SoDA is a flexible, powerful documentation tool that can help you publish project documents by retrieving information from your project software tools.
SoDA is an acronym for Software Documentation Automation.
SoDA is a report generation tool that supports reporting and formal documentation requirements for defining custom reports and documents.
The primary function of SoDA is to retrieve information from various sources and use it to generate a document or report according to a template.
SoDA comes with several predefined templates, or you can use its template-building component to build templates for your specific needs.
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory

20. SoDA for Word
What
Adds document generation to the capabilities of Microsoft Word
Performs incremental document regeneration to reduce turnaround time
Preserves data entered directly into the document from generation to generation
Enables extraction of data from multiple information sources, such as Rational Rose and Rational RequisitePro, to create a single document
Maintains consistency between documents and information sources
Amirkabir University of Technology, Computer Engineering Faculty , Intelligent Systems Laboratory