The kernel is responsible for creating and destroying processes and handling their connections (input and output) with the outside world. The communication between different processes (through signals, pipelines or communication primitives between processes) is the basis of the whole system function and is also handled by the kernel. In addition, the scheduler that controls how a process uses the CPU is part of process management. More generally, the process management activities of the kernel realize the abstraction of multiple processes on a single CPU or several CPUs.