GNU Mach is the microkernel upon which a GNU Hurd system is based. It provides an Inter Process Communication (IPC) mechanism which the Hurd uses to define interfaces for implementing in a distributed multi-server fashion the services a traditional operating system kernel provides. Mach is particularly well-suited for SMP and network cluster techniques. Thread support is provided at the kernel level, and the kernel itself takes advantage of that. Network transparency at the IPC level makes resources of the system available across machine boundaries.
SCHED_DEADLINE is an implementation of a new scheduling class for the Linux kernel. It implements the real-time scheduling algorithm called Earliest Deadline First (EDF). A key feature is that it ensures "temporal isolation", which means that the temporal behavior of each task (i.e., its ability to meet its deadlines) is not affected by the behavior of any other task in the system. In other words, even if a task misbehaves, it is not able to exploit larger execution times than the amount it has been allocated. Each task is characterized by a "budget" and a "period" equal to its deadline. At any instant of time, the system schedules the task having earliest deadline.