ABSTRACT
One of the goals of SE is completeness, that is, to make sure that every aspect of the system has been covered and incorporated into the design. An interface is a boundary between two system elements. Yet it is much more; interfaces are one of those completeness areas which, in traditional engineering, suffer from insufficient treatment, with resultant risk and possible harmful consequences. Alexander (1964) says that a good system is one with the fewest number of misfits. In addition, Rechtin (1991, p. 29) points to the importance of interfaces in the architecting of a system. But, of course, we know that any system should meet its top-level requirements as well, as discussed in Section 4.2.
