Interface Specification

Software systems must be able to work with systems that are already implemented and installed. Thus, interfaces between them must be precisely specified. Specifications related to interfaces must be included in the requirements document as early as possible.

Types of interfaces

1. Procedural interfaces

Application Programming Interfaces (API) are the procedural interfaces. Any service offered by a program or sub-system can be accessed by invoking an interface procedure.

2. Data structures

A sub-system may pass data structures to another sub-system. To describe these structures, Java or C++ automatically generated descriptions or graphical data models are used.

3. Representations of data

The way data is represented, for example, bit ordering, can be used as an interface. Most of the real-time embedded systems use these interfaces. Moreover, Ada also supports them.