non-functional requirement | how it will be implemented in order to give the designer as much freedom as possible to make decisions | | if cost-benefit analysis shows that it will have minimum benefit but still cost a lot to develop | a natural language such as English (using present tense and active voice), sometimes supplemented by a formal mathematical language, and often by some form of diagram | benefits that outweigh the costs of development | all stakeholders | if there is any doubt whether it is realistic | verifiable by measuring various aspects of the system and seeing if the measurements conform with the requirement | various stakeholders, other software systems and any documentation that might be available | a customer's problem | requirement | 4.5 - Types of Requirements | a fact | a diagram | a constraint that must be adhered to during development | a system of sufficient quality - one that is sufficiently usable, safe, efficient, reliable and maintainable | other requirements into a requirements document | the freedom of software engineers as they make design decisions because it limits what resources can be used and sets bounds on aspects of the software's quality | a unique number for traceability | whenever the benefits of doing so outweigh the costs | problem statement | A requirement that constrains design of a system, but does not describe a service that the system is to provide | | clear and consistent notation, using language that the customers can understand, and consistent with the other requirements | the design of the system |
response time | how it will be implemented in order to give the designer as much freedom as possible to make decisions | instantaneous for some operations such as tracking the cursor, popping up of menus and echoing of input | if cost-benefit analysis shows that it will have minimum benefit but still cost a lot to develop | a natural language such as English (using present tense and active voice), sometimes supplemented by a formal mathematical language, and often by some form of diagram | benefits that outweigh the costs of development | all stakeholders | if there is any doubt whether it is realistic | more than 15-20 seconds unless the user interface warns the user so the user can do something else while waiting or choose not to perform the operation | various stakeholders, other software systems and any documentation that might be available | a customer's problem | non-functional requirement | 7.5 - Usability Principles | a fact | a diagram | a constraint that must be adhered to during development | a system of sufficient quality - one that is sufficiently usable, safe, efficient, reliable and maintainable | other requirements into a requirements document | the freedom of software engineers as they make design decisions because it limits what resources can be used and sets bounds on aspects of the software's quality | a unique number for traceability | whenever the benefits of doing so outweigh the costs | problem statement | The time that elapses from when a user issues a command to when the system provides enough results so the user can continue his or her work | the slowest hardware that end-users are likely to encounter | clear and consistent notation, using language that the customers can understand, and consistent with the other requirements | the design of the system |