Safety-related systems in machinery:Variety of software

The need for using software also in safety-critical applications is increasing. Programs are getting larger and and the software still has about as many defects as 30 years ago. All this is a challenge for current software designers. New challenges or possibilities are effective software developing methods, such as, iterative and agile methods. They are not yet used much for safety-critical software development. Standards use typically V-model to present the requirements, whereas companies have picked some ideas from agile or iterative methods, mainly for non-safety-critical applications, thus using slightly different approach. The systems are getting so complex that it is difficult to understand the complete performance of a system. Different and perhaps new methods are required for developing complex software. Complex software will be applied soon in safety applications too