As general software use increases its use in safety critical systems increase as well. Preventive measures are taken during every software engineering project, especially for software intended for safety critical systems. Despite all precautions taken problems still manage to find their ways into news headlines. Many problems caused by faulty software have resulted in large losses of resources, money and life. Due to reluctance to utilize software in such systems it is crucial that every program constructed is done so with precision and care. Although impossible to eliminate every potential problem; genuine effort should be put into identifying them and potential problems should be put to rest.
1. Introduction to software safety.
Software is being used in more systems today than ever before, given that fact it comes as no surprise that software use in safety critical systems are also increasing. When the idea of computer programs controlling dangerous machinery came about it scared people and many were reluctant to use them. Early software projects didn't have the advanced process models that we use or the safety guidelines that we use. Because of these premature processes the end product was not efficient as it should have been. Some of the problems that followed had devastating aftermath. .
1.1. Accidents due to software failure.
There have been several software related accidents in the past few years; these are descriptions of a few of them and their causes. The Mars Climate Orbiter (MCO) was intended to orbit the mars atmosphere for a few weeks at low altitude and make various observations. The MCO was lost early and crashed into the Mars surface. The source of the MCO's failure was rather simple calculation errors, English measurements were used opposed to the metric units that were intended. .
The Titan IV B-32/Centaur TC-14/Milstar-3 was a satellite that was intended to orbit the earth and collect data.