PikeOS
PikeOS is a microkernel-based real-time operating system made by SYSGO AG. It is targeted at safety and security critical embedded systems. It provides a partitioned environment for multiple operating systems with different design goals, safety requirements, or security requirements to coexist in a single machine.
If several programs having different criticality levels are to coexist in one machine, the underlying OS must ensure that they remain independent. Resource partitioning is a widely accepted technique to achieve this. PikeOS combines resource partitioning and virtualisation: Its virtual machine environments (VMs) are able to host entire operating systems, along with their applications. Since PikeOS uses paravirtualisation, operating systems need to be adapted in order to run in one of its VMs. Application programs, however, can run unmodified.
Since each VM has its own, separate set of resources, programs hosted by one VM are independent of those hosted by another. This allows for legacy (e.g. Linux) programs to coexist with safety-critical programs in one machine. Unlike other popular virtualisation systems, PikeOS features not only separation of spatial resources, but also strictly separates temporal resources of its client OSes. This allows for hard real-time systems to be virtualised, while still retaining their timing properties. The PikeOS scheduling method is patented.