Lecture Requirement engineering Chapter 5 Requirement specification

Lecture Requirement engineering Chapter 5 Requirement specification. This chapter presents the following content Introduction, general description, system features, external interface requirement, non functional requirements, other requirements.

Requirement Specification

Requirement specification

systematically organize the requirements

arrived during requirements analysis into a Software Requirements Specification (SRS) document

document requirements properly

Developing Software Requirement

Specification, focus of the project 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

The SRS precisely states the functions

and capabilities that a software system

must provide and the constraints that it must respect

SRS document is a contract between the development team and the customer

The SRS is the basis for:

validating the stated requirements and resolving stakeholder conflicts, if any

SRS document concentrates on:

what needs to be done

carefully avoids the solution (“ how to do ”) aspects

The SRS document serves as a contract

between development team and the

customer

Should be carefully written

Modifiable

 changing requirements easily modified when

specifying, designing, coding, implementing

Traceable

A traceable requirement can be linked backward to its origin and forward to the design elements and source code that implement it and to the test cases that verify the implementation as correct

Every software development organization

should adopt one or more standard SRS

templates for its projects

Many people use templates derived from the one described in IEEE Standard 830-1998

This template is suitable for many kinds of

projects, but it has some limitations and

confusing elements

Table of Contents

I Introduction

II General Description

III System Features

IV External Interface requirement

V Non Functional Requirements

VI Other Requirements

I Introduction:The introduction presents an

overview to help the reader understand

how the SRS is organized and how to use it

I Introduction:

Purpose: Identify the product or application whose

requirements are specified in this document

Ex: This SRS describes the software functional and nonfunctional requirements for release 1.0 of the Cafeteria Ordering System (COS) This document is intended to be used by the members of the project team that will implement and verify the correct

functioning of the system Unless otherwise noted, all requirements specified here are high priority

and committed for release 1.0

I Introduction:

Project Scope:Provide a short description of the software being specified and its purpose

Ex: The Cafeteria Ordering System will permit

employees to order meals from the company

cafeteria on-line to be delivered to specified

campus locations A detailed project description is

available in the Cafeteria Ordering System Vision and Scope Document [1] The section in that

document is titled "Scope of Initial and Subsequent Releases"

I Introduction:

Document Conventions: Describe any

standards or typographical conventions, including text styles, highlighting, or

significant notations

I Introduction:

Intended Audience and Reading

Suggestions: List the different readers to

whom the SRS is directed Describe what the rest of the SRS contains and how it is

organized Suggest a sequence for reading

the document that is most appropriate for each type of reader

I Introduction:

References: List any documents or other

resources to which this SRS refers, including

hyperlinks to them if possible

II Overall Description

Product Perspective: Describe the product's

context and origin

Product features: the major features the product contains or the significant functions that it

II Overall Description

Product Perspective:

This defines the relationship this product has in

the entire spectrum of products

It defines who will be responsible for the product

and what business purpose it serves

It also defines what interfaces it may have to

other systems

II Overall Description

Product Perspective sample

 The Cafeteria Ordering System is a new

system that replaces the current manual and telephone processes for ordering and picking up lunches in the Process Impact cafeteria

II Overall Description

Product Features:

List the major features the product contains or

the significant functions that it performs

It provides a summary of all the functions of the

software

A picture of the major groups of requirements

and how they are related, such as a top-level data flow diagram, a use-case diagram, or a class

diagram, might be helpful

II Overall Description

User Classes and Characteristics

 Identify the various user classes that you

anticipate will use this product and describe their characteristics

 List the users involved with the proposed

system including the general characteristics of eventual users (for example, educational

background, amount of product training)

III System features

Functional Requirements

IV External Interface Requirements :

User Interfaces

References to GUI standards

Screen layout or resolution constraints

Message display conventions…

Hardware Interfaces:

the characteristics of each interface between the

software and hardware components of the system

Software Interfaces

 the connections between this product and other software components including databases, operating systems

V Other Requirements:

Define any other requirements that are not covered elsewhere in the SRS

Examples: internationalization requirements

(currency, date formatting, language, international regulations, and cultural and political issues) and

legal requirements

 You could also add sections on operations,

administration, and maintenance to cover

requirements for product installation, configuration, startup and shutdown, recovery and fault tolerance, and logging and monitoring operations