Operating System

Scheduling (Algorithms) Policies (Priority): These are the following different types  of common policies or algorithms: 1)       First Come First Served (FCFS) scheduling: This is non-preemptive technique. A single queue of ready processes is maintained, and the dispatcher always picks the first one. This method does not emphasize throughput, since long processes are allowed to monopolize CPU, For the same reason, the response time with FCFS can be high (with respect to execution time), especially if there is a high variance in process execution times. This is also known FCFS scheduling. Consider the following example of two processes- In the several processes come on different job p1, p2 and p3 respectively, here p2 and p3 jobs required less than or comparatively p1 process (job), but computer run p1 process in the process of FCFS scheduler. P2 and p3 process has in ready queue in waiting process state. Advantages: These are the following advantag...

  Scheduling:              Scheduling is a fundamental operating system function. All computer resources are scheduled before use. Since Microprocessor is one of the primary computer resources, its scheduling is central operating system design. Scheduling refers to a set of policies and mechanisms supported by operating system that controls the order in which the work to be done is completed. A scheduler is an operating system program that selects the next job to be admitted for execution. The main objective of scheduling is to increase CPU utilization and higher throughput is the amount of work accomplished in a given time interval. CPU scheduling is the basis of operating system which supports multiprogramming concepts. By having a number of programs in computer memory at the same time, the CPU may be shared among them. This mechanism improves the overall efficiency of the computer system by getting more work done in less...

  Inter-process Communication and Process Synchronization:             Inter-process communication is a set of programming interfaces that allow a programmer to coordinate activities among different program processes that can run concurrently in an operating system. There are applications that involve each executing multiple processes concurrently. Processes work together to perform application-specific tasks. They are referred to as cooperating processes. Cooperating processes are “loosely” connected in the sense that they have independent private address spaces and run at different speeds. The relative speeds of the processes are not normally known. From time to time, they interact among themselves by exchanging information. An exchange of information among processes is called an interposes communication.             It is stated in that one process cannot access elem...