سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 6500)

(1) A computer is a set of resources for the movement, storage, and processing of data and for the control of these functions. The OS is responsible for managing these resources. (2) Can we say that it is the OS that controls the movement, storage, and processing of data? From one point of view, the answer is yes: By managing the computer’s resources, the OS is in control of the computer’s basic functions. But this control is exercised in a curious way. Normally, we think of a control mechanism as something external to that which is controlled, or at least as something that is a distinct and separate part of that which is controlled. For example, a residential heating system is controlled by a thermostat, which is separate from the heat-generation and heat-distribution apparatus.) This is not the case with the OS which as a control mechanism is unusual in two respects: • The OS functions is the same way as ordinary computer software; that is, it is a program or suite of programs executed by the processor. • The OS frequently relinquishes control and must depend on the processor to allow it to regain control. (3) Like other computer programs, the OS provides instructions for the processor. The key difference is in the intent of the program. The OS directs the processor in the use of the other system resources and in the timing of its execution of other programs; But in order for the processor to do any of these things, it must cease executing, the OS program and execute other programs. Thus, the OS relinquishes control for the processor to do some “useful” work and then resumes control long enough to prepare the processor to do the next piece of work. What was the writer’s main purpose?