Requirements Engineering Lecture 6 Jerzy Nawrocki Requirements Engineering Lecture 6 Standard SRS Jerzy.Nawrocki@put.poznan.pl www.cs.put.poznan.pl/jnawrocki/mse/require/ Copyright, 2000 © Jerzy R. Nawrocki Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 Plan of the lecture Introduction Requirements document Good practices in describing requirements Use scenarios J. Nawrocki, Requirements Eng., Lecture 6

Computer-based systems Jerzy Nawrocki Computer-based systems Software Hardware People Database Documentation Procedures J. Nawrocki, Requirements Eng., Lecture 6 Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 Restraining factors Assumptions Simplifications Limitations Constraints Preferences J. Nawrocki, Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 A good SRS Unambiguous (one interpretation) Verifiable (one can check that req. are met) Complete (responses to invalid input) Consistent (no conflicts between req.) Modifiable (changes are not a big problem) Traceable (origin of each req. is clear) Usable during the Operation and Maintenance Phase J. Nawrocki, Requirements Eng., Lecture 6

Source Documents for Requir’s SRS SRS Ver. n+1 Manual Ver. n J. Nawrocki, Requirements Eng., Lecture 6

Source Documents for Requir’s SD4R: Source document for requirements Types of SD4R: Email Video File Audio Hard(copy) . . . Advice: Try to keep all the SD4Rs as text files J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (1) 1. Introduction 1.1 Purpose of the document 1.2 Scope of the product 1.3 Definitions, acronyms and abbreviations 1.4 References 1.5 Overview of the document J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (2) 2. General description 2.1 Product perspective 2.2 Viewpoints 2.2.1 Stakeholders 2.2.2 Users 2.2.3 Domain 2.2.4 Components 2.3 System architecture and use cases in UML 2.4 General constraints 2.5 Assumptions and dependencies J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (3) 3. Technical requirements 3.1 Functional requirements 3.1.1 Requirement 1 3.1.1.1 Introduction Viewpoint and source(s) Firmness and importance Verifiability and clarity 3.1.1.2 Inputs 3.1.1.3 Processing 3.1.1.4 Outputs J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (4) . . 3.2 External interface requirements 3.2.1 User interfaces 3.2.2 Hardware interfaces 3.2.3 Software interfaces 3.2.4 Communication interfaces 3.3 Performance requirements J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (5) 3.4 Design constraints 3.4.1 Standards compliance 3.4.2 Hardware limitations . . . 3.5 Attributes 3.5.1 Security 3.5.2 Maintainability J. Nawrocki, Requirements Eng., Lecture 6

Requirements document (6) 3.6 Other requirements 3.6.1 Database 3.6.2 Operations 3.6.3 Site adaptation 3.6.4 Training . . . 3.7 Non-technical requirements Appendixes Index J. Nawrocki, Requirements Eng., Lecture 6

Davis’ Principles for RE Understand the problem before you begin to create the analysis model Develop prototypes showing how the human-machine interaction will occur Record the origin of and the reason for every requirement Use multiple views of requirements (data, functional, and behavioural) Prioritise requirements Work to eliminate ambiguity J. Nawrocki, Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 Jerzy Nawrocki Further readings IEEE Guide to Software Requirements specification, ANSI/IEEE Standard 830-1984 I. Sommerville, P. Sawyer, Requirements Engineering, John Wiley & Sons, Chichester, 1997  J. Nawrocki, Requirements Eng., Lecture 6 Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 Jerzy Nawrocki Homework Write SRS for a personal library system. J. Nawrocki, Requirements Eng., Lecture 6 Requirements Eng., Lecture 6

J. Nawrocki, Requirements Eng., Lecture 6 Quality assessment 1. What is your general impression? (1 - 6) 2. Was it too slow or too fast? 3. What important did you learn during the lecture? 4. What to improve and how? J. Nawrocki, Requirements Eng., Lecture 6