Software Architect's Handbook

S-type systems

An S-type system is specifiable in that it has a well-known, exact specification and can be developed to that specification. It can be described formally and the solutions to such systems are well understood. It is not only possible to definitively determine whether the program is correct, it is also possible to provide a completely correct solution. The requirements of S-type systems are unlikely to change and they do not evolve.

An example of such a system is a calculator program or a program that performs very specific mathematical computations. These types of program have logic that will not change. Systems of this type are the simplest of the three types and are rare. As there is little chance of change with these systems, ...