The system requirements are the descriptions of the system services and constraints that are generated during the requirements engineering process. It should be Complete and Consistent.

Types of Requirement

• User Requirements
  • Statements in natural language
  • Diagrams of the services the system provides and its operational constraints.
• System Requirements
  • A structured document
  • Detailed descriptions of the system’s function, services, and operational constraints.
  • Defines what should be implemented

Readers of Different Types of Requirement Specifications / Stakeholders

• User Requirements
  • Client Managers
  • Contractor managers
  • System end-users
  • Client engineers
  • System architects
• System Requirement
  • System end-users
  • client engineers
  • system architects
  • software developers.

Stakeholders in the Mentcare System

• Patients
• Doctors
• Nurses
• Medical Receptionists
• IT Staff

Agile Methods and Requirements

It argues that producing detailed system requirements is a waste of time as requirements change so quickly.

Agile methods usually use incremental requirements engineering and may express requirements as ‘user’ stories

This is practical for business systems but problematic for systems that require pre-delivery analysis (e.g. critical systems) or systems developed by several teams.

Functional and Non-Functional Requirements

• Functional Requirements

  Describe functionality or system services.

  • Services the system should provide
  • What system should not do?

• Non-Functional Requirements

  Define system properties and constraints.

  • Timing Constraints
  • Development Constraints
  • Standards.
  • Security, Reliability, Maintainability, etc.