resource usage | allows others to efficiently plan hardware upgrades |  |
has example you could specify that no more than a certain amount of memory is to be used by the system, and that the system must consume less than 10% of the CPU's time |  |
is a subtopic of 4.5 - Types of Requirements |  |
is specified in terms of the maximum amount of these resources that the system will consume |  |
is a kind of measurement |  |
is a kind of non-functional requirement |  |
non-functional requirement | describes a constraint that must be adhered to during development |  |
must be verifiable by measuring various aspects of the system and seeing if the measurements conform with the requirement |  |
restricts 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 |  |
requirement | can be gathered from various stakeholders, other software systems and any documentation that might be available |  |
changes regularly |  |
has part problem statement |  |
indicates how the system is to behave |  |
is expressed as a fact |  |
is grouped with other requirements into a requirements document |  |
is normally expressed in 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 |  |
may be given a unique number for traceability |  |
may be shown as a diagram |  |
must be agreed upon by all stakeholders |  |
should be analysed if there is any doubt whether it is realistic |  |
should be changed whenever the benefits of doing so outweigh the costs |  |
should be cut if cost-benefit analysis shows that it will have minimum benefit but still cost a lot to develop |  |
should be expressed using clear and consistent notation, using language that the customers can understand, and consistent with the other requirements |  |
should have benefits that outweigh the costs of development |  |
should help solve a customer's problem |  |
should lead to a system of sufficient quality - one that is sufficiently usable, safe, efficient, reliable and maintainable |  |
should not indicate how it will be implemented in order to give the designer as much freedom as possible to make decisions |  |
should not over-constrain the design of the system |  |