Investigation on SIL and the efforts to certify an RTOS according to the different SIL levels

Abstract

In this master thesis work the possibility to certify a real time operating system (RTOS) according to the international standard IEC 61508 has been investigated. The standard is concerned with functional safety in electrical/electronic/programmable electronics in safety related systems. The standard covers both hardware and software. This thesis has focused on the software part of the standard, as applicable to developing an RTOS. The report shows that it is not possible to certify software according to the standard since it does not perform a safety function. It is possible to certify that the software has been developed according to the requirements in IEC 61508, which would be sufficient when using the software in a safety related system. The assessment of the finished system would benefit from this certification, requiring less time and cost during the final certification. There is no need for big changes to the development process, but there is a need to add routines and documentation to be able to claim conformance to the standard.