Linux in Safety-Critical Applications

Modern society depends on a range of systems that need to guarantee the safety of their users and the environment. Therefore it is crucial which operating system is used for such safety-critical systems. This thesis examines the potential use of the operating system kernel Linux, and the GNU/Linux operating system for safety-critical systems. To gain confidence that GNU/Linux can be used as a platform for safety-critical applications, it was examined how Linux is developed and tested by assembling information from relevant literature. This Open Source development model was compared to traditional software development models. It was analyzed, if the current state of development can fulfil the requirements of existing safety-related standards. To further improve the relevance of Linux for safety-critical systems, two projects have been implemented. The first one is a fully automatic test suite for kernel-level software RAID-1 systems, the second one is a wrapper file system that detects and corrects faulty data on hard disks. It turns out that the Open Source development approach taken by the GNU/Linux community is not a limiting factor for its use in safety-critical applications. Most standards that deal with safety-critical systems are flexible enough to certify systems that are developed in new and open ways. As a result, Linux should be considerd as a platform for safety-critical systems. The development of Linux made large progress during the last years, which makes Linux fit for safety-critical systems.