"The scheduler is the component of the kernel that selects which process to run next. The scheduler (or process scheduler, as it is sometimes called) can be viewed as the code that divides the finite resource of processor time between the runnable processes on a system. The scheduler is the basis of a multitasking operating system such as Linux. By deciding what process can run, the scheduler is responsible for best utilizing the system and giving the impression that multiple processes are simultaneously executing.
"The idea behind the scheduler is simple. To best utilize processor time, assuming there are runnable processes, a process should always be running. If there are more processes than processors in a system, some processes will not always be running. These processes are waiting to run. Deciding what process runs next, given a set of runnable processes, is a fundamental decision the scheduler must make..."
