CASE # 6

WHY IS THERE IS NO TRANSITION FOR

READY TO WAITING

 AND

WAITING TO RUNNING?

The diagram explains that the job before execution will be called or stayed as in ready state. When execution or during execution the said job is now in the running state. If during the execution an interrupt will occur, it will be sent back to in a ready state. But if not, the job’s execution will continue until it is done in its execution. Yet, if during the execution an input/output request page fault will be seen, the CPU will then sent the said job to waiting state. Then as the CPU send a command or a signal for the job on the waiting state to be processed again, from waiting state the job will then change to ready state.

From ready to waiting state:

            In the diagram, we could see that there is no transition to ready state to waiting state. Well, there is no transition for ready to waiting state due to all failed required devices are to be sent to hold. A job can be in the ready state when the said job is okay in all aspects. When it is now ready the CPU then execute the job or from ready state it is now in the running state. It is impossible to have a transition from ready to waiting because from ready state the job will automatically be sent on a running state. If during the execution (like what I have said awhile ago) an interrupt issued, because in executing jobs we cannot say that there will be no interruption, from the running state will turn back to ready state. After the interruption the job that is sent back to ready state will be loaded or executed again.

From waiting to running:

            It is impossible for a transition from waiting to running state, if we look at the diagram. Why? Because the CPU cannot send signals to job in the waiting state to automatically send in the running state whatever happens. It only means that a job can be on the running state if and only if it is ready or in the ready state. During at the waiting state, the CPU can only send signals that command the job to be at the ready state before its actual execution or the running state.