Types of scheduling - Long and medium term scheduling
In single task operating systems the issue of scheduling is trivial: after the system has set up the execution environment of a process, CPU control is given to it until the process itself exits. In a pun, the system is not operating at all during the program's execution, save for providing services through subroutine calls. It's only with multi-tasking operating systems that scheduling becomes a top entry in a designer's agenda.
In many multitasking systems the processor scheduling subsystem operates on three levels, differentiated by the time scale at which they perform their operations. In this sense we differentiate among:
In single task operating systems the issue of scheduling is trivial: after the system has set up the execution environment of a process, CPU control is given to it until the process itself exits. In a pun, the system is not operating at all during the program's execution, save for providing services through subroutine calls. It's only with multi-tasking operating systems that scheduling becomes a top entry in a designer's agenda.
In many multitasking systems the processor scheduling subsystem operates on three levels, differentiated by the time scale at which they perform their operations. In this sense we differentiate among: