12.2 System Specification Aspects

12.2.1 The Specification Problem – Again

The problems encountered in defining system requirements (specifications) have already been well and truly covered. But let's assume that we have managed to produce a complete statement of requirements (SOR) for a critical system (or so we think):

Figure 12.8: Sources of software-related faults

Now, at this point, some very important questions should be asked:

• Are the system specifications clear, understandable, and unambiguous?
• Can we be absolutely sure that they are consistent and complete?
• Can we, as the specifiers, be absolutely sure that the software designers correctly and fully understand these requirements?
• Can we review the proposed design to check its correctness (that is, does it meet its specification)?

Note well this last point: the check for correctness. To do this, we compare the program (text) whose syntax is defined formally...