1. Job scheduler is also called long term scheduler and CPU scheduler is called short term scheduler.
2. Job scheduler selects the processes from the job pool and load them in to the memory for execution. in other hand CPU scheduler selects among the processes that are in ready to execute and allocate the CPU to one of them.
3. CPU scheduler is faster than the process scheduler.
Read more: What_is_the_difference_between_the_job_scheduler_the_CPU_scheduler
1.) in preemptive scheduling we prempt the currently executing process, in non preemptive scheduling we allow the current process to finish its CPU burst time... 2.) in preemptive scheduling the process is forcibly sent to waiting state when a process with higher priority comes to CPU, in non preeemptive scheduling the process at running state can not be forced to leave the CPU until it completes........
In Non-Primitive CPU Algo. once a process is given to the CPU it cannot be preempt,but in primitive Algo. it can be.
Preemptive scheduling allows a process to be interrupted in the midst of its execution, taking the CPU away and allocating it to another process.Non-preemptive scheduling ensures that a process relinquishes control of the CPU only when it finishes with its current CPU burst.
Preemptive scheduler reruns scheduling decision when process becomes ready. If the new process has priority over running process, the CPU preempts the running process and executes the new process. Non-preemptive scheduler only does scheduling decision when running process voluntarily gives up CPU. In effect, it allows every running process to finish its CPU burst.
The priority scheduling algorithm is a kind of CPU scheduling algorithm where the processes that wait for the CPU are scheduled according to their priority..
the objective of multiprograming is to have some processs running at aal time,so as to maximizing cpu utillization .this process is called scheduling.
Non pre-emptive means once CPU starts executing one process, it will not be taken out of the CPU until it is terminated or it has to wait for some event. In preemptive SJF scheduling, current running process is moved to the ready queue when a new process with a shorter CPU burst joins the ready queue.
The difference between a 32 bit and 64 bit CPU is the speed in which a computer will read and process the information. A 64 bit CPU will read much quicker and can handle the memory usage better than a 32 bit.
By far the simplest CPU-scheduling algorithm is the first-come, first-served (FCFS) scheduling algorithm. With this scheme, the process that requests the CPU first is allocated the CPU first. The implementation of the FCFS policy is easily managed with a FIFO queue. When a process enters the ready queue, its PCB is linked onto the tail of the queue. When the CPU is free, it is allocated to the process at the head of the queue. The running process is then removed from the queue. The code for FCFS scheduling is simple to write and understand. The average waiting time under the FCFS policy, however, is often quite long. Consider the following set of processes that arrive at time 0, with the length of the CPU-burst time given in milliseconds:
So that CPU utilise all the resources of OS
Under non-preemtive scheduling ,once the CPU has been allocated to process ,the process keeps CUP until it release CPU either terminating or switching to the waiting state . Bharat Rawal
Under non-preemtive scheduling ,once the CPU has been allocated to process ,the process keeps CUP until it release CPU either terminating or switching to the waiting state . Bharat Rawal