Lesson 6

Question 1

The descriptions of what the system should do —the services that it provides and the constraints on its operation

Answer 1

Requirements

Question 2

reflect the needs of customers for a system that serves a certain purpose such as controlling a device, placing an order, or finding information

Answer 2

Requirements

Question 3

The process of establishing the services that a customer requires from a system and the constraints under which it operates and is developed.

Answer 3

Requirements Engineering

Question 4

The system requirements are the descriptions of the system services and constraints that are generated during the requirements engineering process.

Answer 4

Requirements Engineering

Question 5

high-level abstract requirements

Answer 5

User Requirements

Question 6

statements, in a natural language plus diagrams, of what services the system is expected to provide to system users and the constraints under which it must operate

Answer 6

User Requirements

Question 7

more detailed descriptions of the software system’s functions, services, and operational constraints (what the system should do)

Answer 7

System Requirements

Question 8

(sometimes called a functional specification) should define exactly what is to be implemented

Answer 8

System Requirements

Question 9

It may be part of the contract between the system buyer and the software developers

Answer 9

System Requirements

Question 10

What are the Readers of Different Types of Requirements Specification?

Answer 10

The readers of the user requirements are not usually concerned with how the system will be implemented and may be managers who are not interested in the detailed facilities of the system

The readers of the system requirements need to know more precisely what the system will do because they are concerned with how it will support the business processes or because they are involved in the system implementation

Question 11

Any person or organization who is affected by the system in some way and so who has a legitimate interest

Answer 11

System Stakeholders

Question 12

What are the types of stakeholders?

Answer 12

• End users
• System managers
• System owners
• External stakeholders

ESSE

Question 13

statements of services that the system should provide

Answer 13

Functional Requirements

Question 14

It may explicitly or not states what the system should and should not do

Answer 14

Functional Requirements

Question 15

These requirements depend on the type of software being developed, the expected users of the software, and the general approach taken by the organization when writing requirements

Answer 15

Functinal Requirements

Question 16

usually described in an abstract way that can be understood by system users o More specific functional system requirements describe the system functions, its inputs and outputs, exceptions, etc., in detail

Answer 16

Functional user requirements

Question 17

Varies from general requirements covering what the system should do to very specific requirements reflecting local ways of working or an 11 organization’s existing systems

Answer 17

Functional system requirements

Question 18

functional requirements specification of a system should be both what?

Answer 18

Complete and concise

Question 19

means that all services required by the user should be defined

Answer 19

Completeness

Question 20

means that requirements should not have contradictory definitions

Answer 20

Consistency

Question 21

Requirements that are not directly concerned with the specific services delivered by the system to its users

Answer 21

Non-Functional Requirements

Question 22

They include timing constraints, constraints on the development process, and constraints imposed by standards

Answer 22

Non-functional Requirements

Question 23

often apply to the system as a whole, rather than individual system features or services

Answer 23

Non-functional requirements

Question 24

Failing to meet a non-functional requirement can mean what?

Answer 24

the whole system is unusable

Question 25

What are the types of non-functional requirements?

Answer 25

* Product requirements, * organizational requirements, * external requirements **POE**

Question 26

# type of non-functional requirements These requirements specify or constrain the behavior of the software.

Answer 26

Product Requirements

Question 27

# type of non-functional requirements These requirements are broad system requirements derived from policies and procedures in the customer’s and developer’s organization

Answer 27

Organizational Requitements

Question 28

# type of non-functional requirements This broad heading covers all requirements that are derived from factors external to the system and its development process

Answer 28

External Requirements

Question 29

An official statement of what the system developers should implement

Answer 29

Software Requirements Specification Document

Question 30

The process of writing down the user and system requirements in a requirements document

Answer 30

Requirements Specification

Question 31

The user and system requirements should be what?

Answer 31

clear, unambiguous, easy to understand, complete, and consistent **CUECC**

Question 32

What should you not do when writing user requirements?

Answer 32

You **should not** use software jargon, structured notations, or formal notations. You **should** simply describe the external behavior of the system and its operational constraints

Question 33

Invent a standard format and ensure that all requirement definitions adhere to that format

Answer 33

Natural Language Requirements Specification Guidelines

Question 34

How should you pick out key parts of the requirement?

Answer 34

text highlighting (bold, italic, or color)

Question 35

How should you write mandatory and desireable requirements?

Answer 35

Mandatory requirements are requirements that the system must support and are usually written using **‘shall’** Desirable requirements are **not essential** and are written using **‘should'**

Question 36

What is The Requirements Engineering Process?

Answer 36

* Feasibility study * Requirements elicitation and analysis * Requirements specification * Requirements validation * Requirements management **FESVM** or **FRRRR**

Question 37

an iterative process that can be represented as a spiral of activities

Answer 37

Requirements elicitation and analysis

Question 38

What are the activities in Requirements elicitation and analysis?

Answer 38

— requirements discovery, requirements classification and organization, requirements negotiation, and requirements documentation **DCND**

Question 39

# Requirements elicitation and analysis This is the process of interacting with stakeholders of the system to discover their requirements

Answer 39

Requirements discovery

Question 40

# Requirements elicitation and analysis Domain requirements from stakeholders and documentation are also discovered during this activity

Answer 40

Requirements discovery

Question 41

# Requirements elicitation and analysis This activity takes the unstructured collection of requirements, groups related requirements, and organizes them into coherent clusters

Answer 41

Requirements classification and organization

Question 42

# Requirements elicitation and analysis This activity is concerned with prioritizing requirements and finding and resolving requirements conflicts through negotiation

Answer 42

Requirements prioritization and negotiation

Question 43

# Requirements elicitation and analysis Usually, stakeholders have to meet to resolve differences and agree on compromise requirements

Answer 43

Requirements prioritization and negotiation

Question 44

# Requirements elicitation and analysis The requirements are documented and input into the next round of the spiral

Answer 44

Requirements specification

Question 45

# Requirements elicitation and analysis Formal or informal requirements documents may be produced

Answer 45

Requirements specification

Question 46

The process of checking the requirements for validity, consistency, completeness, realism, and verifiability

Answer 46

Requirements validation

Question 47

It is the process of checking that requirements actually define the system that the customer really wants

Answer 47

Requirements validation

Question 48

It overlaps with analysis as it is concerned with finding problems with the requirements

Answer 48

Requirements validation

Question 49

Why is Requirements validation important?

Answer 49

is important *because errors in a requirements document can lead to extensive rework costs* when these problems are discovered during development or after the system is in service

Question 50

What are the different types of checks used in requirements validation?

Answer 50

* Validity Checks * Consistency Checks * Completeness checks * Realism Checks * Verifiability **VCCRV**

Question 51

# Requirements validation A user may think that a system is needed to perform certain functions. However, further thought and analysis may identify additional or different functions that are required. Systems have diverse stakeholders with different needs and any set of requirements is inevitably a compromise across the stakeholder community

Answer 51

Validity checks

Question 52

# Requirements Validation Requirements in the document should not conflict

Answer 52

Consistency Checks

Question 53

# Requirements Validation There should not be contradictory constraints or different descriptions of the same system function

Answer 53

Consistency checks

Question 54

# Requirements Validation The requirements document should include requirements that define all functions and the constraints intended by the system user

Answer 54

Completeness checks

Question 55

# Requirement Validation Using knowledge of existing technology, the requirements should be checked to ensure that they can actually be implemented

Answer 55

Realism Checks

Question 56

# Requirements Validation These checks should also take account of the budget and schedule for the system development

Answer 56

Realism Checks

Question 57

# Requirements validation To reduce the potential for dispute between customer and contractor, system requirements should always be written so that they are verifiable

Answer 57

Verifiability

Question 58

# Requirements Validation This means that you should be able to write a set of tests that can demonstrate that the delivered system meets each specified requirement

Answer 58

Verifiability

Question 59

Business, organizational, and technical changes inevitably lead to changes to the requirements for a software system

Answer 59

Requirements management

Question 60

Requirements management is the process of understanding, managing and controlling changes to system requirements

Answer 60

Requirements management

Question 61

What are the several reasons why change is inevitable?

Answer 61

1. **The business and technical environment of the system always changes after installation** - New hardware may be introduced, it may be necessary to interface the system with other systems, business priorities may change (with consequent changes in the system support required), and new legislation and regulations may be introduced that the system must necessarily abide by 2. **The people who pay for a system and the users of that system are rarely the same people System customers impose requirements because of organizational and budgetary constraints ** - These may conflict with end-user requirements and, after delivery, new features may have to be added for user support if the system is to meet its goals 3. **Large systems usually have a diverse user community, with many users having different requirements and priorities that may be conflicting or contradictory ** - The final system requirements are inevitably a compromise between them and, with experience, it is often discovered that the balance of support given to different users has to be changed

Question 62

When should you apply Requiremnts Change Management?

Answer 62

Requirements change management should be applied to all proposed changes to a system’s requirements after the requirements document has been approved

Question 63

Why is Requirements Change Management essential?

Answer 63

Change management is essential because you need to decide if the benefits of implementing new requirements are justified by the costs of implementation

Question 64

What are the stages of Requirements Change Management?

Answer 64

1. Problem Analysis and Change Specification 2. Change Analysis and Costing 3. Change Implementation **PCC**

Question 65

# Principal stages of Requirements change management The process starts with an identified requirements problem or, sometimes, with a specific change proposal

Answer 65

Problem analysis and change specification

Question 66

# Principal stages of Requirements change management During this stage, the problem or the change proposal is analyzed to check that it is valid

Answer 66

Problem analysis and change specification

Question 67

# Principal stages of Requirements change management This analysis is fed back to the change requestor who may respond with a more specific requirements change proposal, or decide to withdraw the request

Answer 67

Problem analysis and change specification

Question 68

# Principal stages of Requirements change management The effect of the proposed change is assessed using traceability information and general knowledge of the system requirements

Answer 68

Change analysis and costing

Question 69

# Principal stages of Requirements change management The cost of making the change is estimated both in terms of modifications to the requirements document and, if appropriate, to the system design and implementation

Answer 69

Change analysis and costing

Question 70

# Principal stages of Requirements change management Once this analysis is completed, a decision is made whether or not to proceed with the requirements change

Answer 70

Change analysis and costing

Question 71

# Principal stages of Requirements change management The requirements document and, where necessary, the system design and implementation, are modified

Answer 71

Change implementation

Question 72

# Principal stages of Requirements change management You should organize the requirements document so that you can make changes to it without extensive rewriting or reorganization

Answer 72

Change implementation

Question 73

As with programs, changeability in documents is achieved by minimizing external references and making the document sections as modular as possible

Answer 73

Change implementation