Understanding Requirements - Requirements Engineering and Management for Software Development Projects - page 14

Fig. 2.2 Ancillary functionality requirements

processes using the software becomes tedious. That is the reason, I have not used
the ''functional and non-functional'' classification of requirements.
In almost all cases of software development, core functionality is addressed
completely. The customer provides core functionality in project scenario. It is
defined by the project team or domain experts in the case of a product development
scenario. But when it comes to ancillary functionality, it is common to miss out on
some of the ancillary functionality. In many cases where the end product of
software development is panned by the critics, the criticism stems from the fact
that all relevant ancillary functionality is not fully or not efficiently implemented.
Various classes of statutory functionality requirements is depicted pictorially in
Fig. 2.2 .
The following are the ancillary functionalities that need to be included in the
overall requirements for the project:

1. Statutory functionality—This functionality is required because of regulations/
standards of government, or industry associations or professional associations.
In software development industry we have Institute of Electrical and Electronics
Engineers (IEEE), Software Process Improvement Networks (SPINs), Soft-
ware Project Managers Networks (SPMNs) in addition to governments.