Static Inspection: Tapping the Wheels of Software

Static inspection is about the removal of obvious fault or inconsistency before a prod uct is even tested. It forms an indispensable part of all conventional engineering disciplines except for software engineering. For example, when a microcomputer is reviewed, the reviewer will inevitably remove the case, exposing the boards to inspect their quality of build, and make astute judgemen t s as to the long-term behaviour of the machine. Before a person buys a house, it is inspected for struct ur al and many other problems. It would be nice to think that all software engineering was subject to the same degree of care. It would be nice to think that after careful rumination by an impressive number of qualified people who together comprise a standar d s committee, the resulting program ming language came into the world in a safe, well-defined and unambiguous manner, suitable for use by program m e r s necessarily less knowledgeable about the language. It would be nice to think that any resulting transgressions to this safe, complete and unambiguous language definition, would be immediately detected by a compiler before they can cause any damage, and the program m er responsible informed of this fact in a straightforwar d manner. In such a world, elephant s fly and dreams always become reality. In our world, nothing could be farther from the truth. In spite of the best efforts of our language experts, we continue to produce program ming languages, which are not only unsafe, but frequently fail to acknowledge the fact. Compiler-writers compoun d the misery by providing compilers which are allowed to turn a blind eye to safety in obeisance to the great one-eyed god "Performance". Modern languages such as Ada, Fortran 90 and C+ + further compoun d the misery by being very complex, and consequently exceedingly difficult to understa nd, and therefore difficult for which to write high-quality dependable compilers. As a result, much of the world's software in various languages is released full of inconsistencies, waiting for the right opport u nity to develop into a real failure. These work in consort with inaccuracies in capturing the specification to reduce the reliability and safety of our software in an era when software becomes ever more pervasive with many tens of thousand s and sometimes millions of lines of code in autom obiles, televisions, fire alarms, medical scanners and aircraft. To …