Unit 2 Key Points

Question 1

Functional requirement

Answer 1

A functional requirement specifies the behaviour of the system.
A functional requirement is something the system must do.

Question 2

User Story

Answer 2

Describes some functionality that is of value to the person writing the story.

‘As a customer I can see days, times and cost of flights to the destination’

Question 3

What are the nature of requirements?

Answer 3

Unstable - can change with the environment.

Many stakeholders with conflicting priorities.

Requirements are not clearly identifiable.

Question 4

What are Requirements properties and definitions?

Answer 4

Necessary and traceable.
Non-ambiguous and realistic.
Complete.
Consistent.
Verifiable and validated.

Question 5

actor

Answer 5

A representation of users of a software system in a particular role, when interacting with use cases. An actor can also represent the role of an external system that interacts

Question 6

Non-Functional requirement (NFR)

Answer 6

NFRs are qualities that the system must have - fast, secure, maintainable etc.
NFRs constrain the system architecture.

Question 7

What are the eight NFRs specified by Robertson and Robertson?

Answer 7

Look-and-feel requirements. 
Usability and humanity requirements. 
Performance requirements. 
Operational and environmental requirements. Maintainability and support requirements.
Cultural requirements. 
Legal requirements. 
Security requirements.

Question 8

What is an example of a Look and Feel Requirement?

Answer 8

Some examples of look-and-feel requirements are:

The product shall comply with the iOS human interface guidelines.
The product shall use only two colours.
The product should use a lot of animation.
The product shall use a large range of exciting sounds.

Question 9

What is an example of a performance requirement?

Answer 9

Some examples of performance requirements are:

The product shall calculate a guest’s bill in 2 seconds
The product shall handle up to 10 users simultaneously
The product shall report wind speeds within 5mph of the actual speed.
The product shall, on average, operate without failure for 20 days.

Question 10

What is an example of a usability and humanity requirement?

Answer 10

Some examples of usability and humanity requirements are:

A university graduate should be able to learn to use 50 per cent of the functionality of the product in 2 hours.
Ninety per cent of the general population should be able to place an order from a web interface within 5 minutes.
It should be possible to use the system to pay in different currencies.
The system should comply with the Disability Discrimination Act.

Question 11

What is an example of an operational and environmental requirement?

Answer 11

Some examples of operational and environmental requirements are:
The product shall be usable above an altitude of x, in icy and wet conditions, and both in the dark and in bright sunshine.
The product will be used in a standard office environment, except that high levels of background noise may occur.
The product will need to be installed at 58 locations around the proposed route of the race in 2 days by 3 semi-skilled workers.