When You Run a Job

At the start

You may leave the decision of when to execute your job to the computer. Or, within limits, you may increase the priority of your job in the job queue in order to have it execute sooner.

Alternatively, you may specify a time (a time of day, a day of the week, a week of the month, even another year) for your job's execution. And at that time, if the computer has resources available, it will execute your job.

The command to start a job executes almost immediately, and, just as quickly, the computer returns control of your terminal to you.

Before returning control of your terminal to you, the computer will display the job identification number assigned to your job. It might be J345, meaning that yours is job number 345 in a sequence of jobs that were launched since the job counter was reset.

This done, you may continue with other work. You have only to wait for the job to execute and finish and then examine the job listing on your printer.

	Worth Remembering: Record the job identification number of your job. While the job is running, this number is your link with the job. You may want to do several things that are possible if you know the job number. Among them are: monitor the job status (SHOWJOB) suspend the job (BREAKJOB) resume the job (after suspending it) RESUMEJOB terminate the job (ABORTJOB) obtain status reports on any spool files associated with your job (LISTSPF)

These and other commands, along with the JOB command, are discussed in greater detail in &USING; and in the &help;.

Your job--your list of commands for execution--is transformed into an input spool file and, like all other input spool files, waits its turn to execute. It may wait a few seconds, a few minutes, or even a few hours before executing. In the meantime, you may continue with other work on your terminal.

Job priority

Jobs are executed in the order of their priority, and priorities range from 1 (the lowest) to 13, with HIPRI (the highest) reserved for your system manager or system operator. If you do not specify a priority when you create your job file, your job will be assigned a priority of 8, which is just above the halfway point in the range of priorities.

If two jobs have equal priority, the job that was started earlier takes precedence. Here, "started" means that a job was sent to the computer for processing by using the STREAM command.

Getting over the fence

Your system manager or system operator will use the JOBFENCE command to set the priority limits for jobs. If the jobfence is set at 7 and your job has a priority of 8, it will eventually execute, but only after jobs having a priority of 9 or greater have executed. If your job has a priority equal to or less than 7 (the same as the jobfence), it will not run.

If the jobfence is set at HIPRI, no jobs except those given HIPRI priority will execute. Only a system administrator or a system operator is able to assign HIPRI to a job.

JOBFENCE gives your system manager or system operator a means of controlling the flow of job traffic on your system.

When you create a job, you may use the JOB command and its ;INPRI keyword to increase the input priority of your job, even before you launch it. Decreasing the input priority to 1 insures that the job will never run--occasionally useful if you want to put a job "on hold."

You may use the SPOOLF command with the ;ALTER and ;PRI= parameters to increase (or decrease) the output priority of the spool files that are generated by your job.

	TIP: It is tempting to give your jobs (or output spool files) the highest possible priority and race to the head of the line. Some jobs truly do deserve higher priority--but only some.

Scheduling

The STREAM command includes the keywords ;AT, ;DAY, ;DATE, and ;IN. These keywords permit you to set the start time for a job at a particular time, on a particular day, on a particular date, or in a number of days, hours, or minutes (from now).

Errors and your job listing

If there are errors in your job file--or if the computer cannot complete an instruction in the job file--the computer will display on your video terminal nothing more than a message telling you that your job terminated in an error.

During a session, the computer displays error messages on your terminal ($STDLIST for a session). During a job, however, $STDLIST is redirected to the printer connected to your MPE/iX system, and that is where your error listing appears.

This redirection of information is, in fact, quite sensible. Your computer has no way of knowing whether you will be at your terminal when your job executes, whether your terminal will even be turned on, or whether you will have gone home for the evening.

To find the source of an error in your job, you must go to your printer and examine the job listing. The job listing is the printed report that your job delivers whether the job completed successfully or failed at some step along the way. It gives you confirmation of each command in the job, telling you whether the command executed successfully or failed--and if it failed, what error caused the failure.