Lecture 1 Flashcards
What is a socio-technical system?
Socio-technical system involves human, organisational, hardware and software components that interact and depend upon each other in **complex ways **
What is the definition of a requirement?
Is an expression of something required that is shared by the system under specification and its environment –
Each requirement statement shall express both the system and the environment – this is a minimum perquisite for a valid requirement
What is Common anatomy of a good requirement?
- *Actor type**: actor benefiting from the requirement
- *Result type**: the MAIN verb
- *Desirable state**: for actor to reach – normally an object and qualifier statement that hints at the **fit criterion **
Good requirements Examples
Actor type: the registered user… / The banking system
Result type: VERB …shall be able to purchase… / …shall authorise…
Object: … desired tickets… / …take payments…
Qualifier: EASE OF USE…easily / …reliably
Words to avoid when writing requirements
Ambiguous terms: “OR”
Conjunction words: “AND” + “or”
Let-out clauses: “if”, “when”, “but”, “except”, etc.
“usually”, “generally”, “often”
Possibilities: “may”, “might”, “should”, “could”, “probably”
What does EARS stand for?
Easy Approach to Requirements Syntax
VOLERE Template Explanation
Requirement: must be uniquely identified
Requirement Type: Categorises the TYPE of requirement
Description: describes the intent of the requirement
Rationale: the reason behind the requirements existence to help clarify and understand
Source: The name of the person or group who raised the requirement
Fit-criterion: Qualified goals that the product has to meet
Customer satisfaction: The satisfaction ranking
Performance requirement
- For example 1000 purchases measures the way the website system responds sufficiently quickly for 995 of the 1000 events.
- Defines which browsers, devices and interconnection speeds the specified performance should hold for.
- Measure elapsed time between two events using internal software monitor to produce a log that a human analyst can draw **conclusions **
Reliability requirement
Mean-times between failures or to failure over a period to fit criterion – assume that a failure log is generated and maintained using purposefully designed software, analysed by a human analyst to determine failure.
Usability requirement
Defines the events to measure, define what you are measuring and analyse a **compliance test **
Specifies the desirable property of the registered user rather than the system. This is based on the data collection from a **large number of registered users **
Functional requirements
Is an expression of something either a service. behaviour or function that a future product or system must do
Non-Functional
Express the desirable qualities of the product (For example, a portable computer should be light, cheap, reliable and robust)
