1) Speed
it is measured in terms of screen refresh time, user or event response time, the number of transactions being processed per second.
2) Portability
Percentage of statements directly dependent on the targets to be achieved.
A total number of target systems available.
3) Ease of Use
The total number of help frames required.
Time spent in training.
4) Robustness
Estimation of the amount of data that can get corrupted during the time of failure.
Percentage of events which may remain a cause for failures.
The time required in order to restart the system after a failure.
5) Size
The number of ram chip.
bytes
6) Reliability
Availability.
Meantime to failure.
Rate of occurrence of failure.
Probability of unavailability.
These metrics may be used fruitfully during the system testing in order to ensure that the systems meet all its specified non-functional requirements.
User Requirements:
1. Both functional and nonfunctional requirements are described briefly and without any technical details in the user requirements so that they can be understood by system users.
2. The details should only provide the external behavioral aspects of the system.
3. Hence, it should not include its implementation details which may frustrate the nontechnical users.
4. The details should be concluded by encompassing diagrams, forms, tables, etc., to a major extent.
5. Apart from this, there may be certain other problems that may evolve due to the natural language used in writing these specifications.
6.Requirements Amalgamation: This problem usually whenever we club several requirements and specify it as one.
7.Lack of clarity: This specification often turnouts to be lengthy and the data may not include the required information.
8.Requirements confusion: This problem usually arises whenever we do not specify the clear distinction between non-functional, functional requirements, design information and also system goals respectively.
9. Also while writing user requirements, one has to remember that it should not be included along with the details of system requirements.
10. User requirements should be precise.
System Requirements:
1. System requirements are often termed to be the initial step in the system designing process.
2. They prescribe the implementation details of the user requirements.
3. Hence, they are a certain extent related to them, but at the same time, they are more detailed than them.
4. The data within the system requirement should be complete as well as consistent.
5. While dealing with system requirements one has to remember the fact that, it should only describe the operational a well as the behavioral aspects of the systems.
6. It has got nothing to do with the implementation as well as the design details of the system.
7. But whenever we come across a large and complex system we cannot just avoid the design details in the system requirements.