Understanding Solution Non-functional Requirements in VCE Innovative Solutions
What it does: Uptime percentage is a measurable non-functional quality, matching this description. Non-functional requirements describe qualities like speed, security, or reliability. Load time is a quality measure, while logging in is a specific action — a functional requirement. Non-functional requirements are established during design, alongside functional requirements. Availability describes how consistently a system can be accessed, making it a non-functional quality.
Common mistakes: Describing a specific action is a functional requirement, not a non-functional one. Non-functional requirements can absolutely be measured, such as by checking load time in seconds.
Quick Questions
1. Does a non-functional requirement describe how well a system performs?
Non-functional requirements describe qualities like speed, security, or reliability.
2. Which is a non-functional requirement: 'must load in 2 seconds' or 'must let users log in'?
A. Must load in 2 seconds ✓
B. Must let users log in
Load time is a quality measure, while logging in is a specific action — a functional requirement.
3. Can non-functional requirements be measured or tested?
Non-functional requirements, like response time or uptime, can be measured and tested.
4. Is security a common example of a non-functional requirement?
Security, along with speed and reliability, is a classic non-functional quality.
5. Are non-functional requirements the same as functional requirements?
Functional requirements describe actions; non-functional requirements describe qualities — they're different.
Fill in the Blanks
1. The system must be fast
Hint: Type the quality describing quick performance
2. The system must respond within 2 seconds
Hint: Type the unit of time the system must respond within
3. A non-functional requirement describes
quality
Hint: Type the word for how well something performs
4. Non-functional requirements describe
qualities
Hint: Type the plural word for the qualities being described
5. Response time is a non-functional requirement
Hint: Type the word for this kind of specification
Spot the Error
Question 1
A
A non-functional requirement describes a specific action to perform.
B
A non-functional requirement describes how well a system performs.
C
It focuses on qualities like speed or reliability.
D
It differs from a functional requirement.
Line A — Describing a specific action is a functional requirement, not a non-functional one.
Question 2
A
"The system must load within 2 seconds" is non-functional.
B
Non-functional requirements can never be measured.
C
It describes a measurable quality, not an action.
D
Non-functional requirements can be tested and measured.
Line B — Non-functional requirements can absolutely be measured, such as by checking load time in seconds.
Question 3
A
Security is a common non-functional requirement.
B
"The system must encrypt passwords" relates to security.
C
Reliability is another example of a non-functional quality.
D
Security requirements only apply to functional requirements.
Line D — Security requirements are a classic example of non-functional requirements, not functional ones.
Question 4
A
"The system must let users log in" is non-functional.
B
Non-functional requirements describe qualities of a system.
C
Examples include speed, security, and usability.
D
These qualities affect the overall user experience.
Line A — Letting users log in describes a specific action, making it a functional requirement, not non-functional.
Question 5
A
Availability describes how often a system is accessible.
B
Availability describes a single user action a system performs.
C
"The system must be available 99% of the time" is an example.
D
Availability is measured as a percentage of uptime.
Line B — Availability describes a system quality, not a single action a system performs.
