Sunday, February 27, 2011

Job and Process Status


Using the process state diagram, explain why there is no transition:

  • ·         From the READY to WAITING.
  • ·         From the WAITING to RUNNING.

We can somehow describe the flow of the diagram by identifying the specific duties of its “States” in the process management. When a particular job is formed it will be engaged in the “Hold State”. The “Holding” queue will then pass on a job scheduler before reaching the “Ready State”. The “Ready” queue will move to the “Running State”. The “Running” queue will be checked if there will be an interrupt or an I/O request. If there are, it will be brought to the “Waiting State”. “Waiting” queue will send signals to the “Ready State” to continue the process and it will be then process again. But if there are non, then the “Running” queue will proceed to another “Job Scheduler” before making into the “finished”. 
Transition is the process through which an existing circumstance, condition, or relationship (real or imagined) is acted on in a manner that produces a new and different circumstance or condition.

From the READY to WAITING.
            I will explain this particular situation by giving an appropriate example. Let just say that job X will be the one that will be process based on the diagram.
            When job X is in the “Ready State” it must first passed the job scheduler. The job scheduler will be the one that will allow a particular job (such as job X) to be process and move to the “Ready State”. The “Ready” queue will soon make use of the CPU (Central Processing Unit) then after that the particular job (job X) will be move on the “Running State” but remember not all job can successfully passed the “Running State” most likely an interrupt will appear. An interrupt on the “Running” queue will be issued on the “Ready State”.
 But if happen that the “Running” queue will be waiting for a device (such as an I/O request) in order to work it will eventually brought to the “Waiting State”. And that how a job processed from the “Ready” to “Waiting State”. As you can observe, no transition happen because the system has been divided on its specific duties in the process management which allows the operation of system to perform accountably.

From the WAITING to RUNNING.
            When job X is supposedly in the “Waiting State” it will release signals to the “Ready State” to continue the processing of the given job. The “Ready State” will recognize the signals and so the “Waiting” queue (job X) will be back then on the “Ready State”. This is because, all incoming jobs in system must go primarily into the “Ready state” and jobs can only enter the “Running state” by passing through the “Ready state”. Shifting directly from “Waiting” to “Running State” without passing through “Ready State” will cause error in the processing of jobs.
            When the “Ready” queue (job X) is set it will directly go to the “Running State”. The “Running” queue waits for any interrupt. If no interrupt or I/O request appears it will then go through another “Job Scheduler” before reaching the “Finished” which is the end of the process. Still no transition has been made because there is no manner that produces a new and different circumstance or condition in process management.   

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