IBM System/34 - Jobs and Job Queues

Jobs and Job Queues

In S/34 parlance, a job is any task the computer has been asked to do. A job has a job number, which for a program is the Workstation ID plus the time in HHMMSS format. For a printout, there's a spool job, which is "SP" and a four-digit suffix which is incremented by 1.

Sometimes a needed report should be run in the background so as not to delay the users. If the parameters of the report are defined, it shouldn't occupy the user's time or occupy that valuable area on the CRT. For this reason, the Job Queue was invented. Imagine the program standing in line waiting to use the computer processor. A job queue has a size (the number of jobs that can be in line) and a value for concurrency (how many lines there are, or, more accurately, job queue jobs that can run at the same time.)

JOBQ OCL

The JOBQ OCL statement causes the job queue job to be initialized, but it won't begin immediately if there's a lineup. This allows some greater control of system resources.

EVOKE OCL

The EVOKE OCL statement also causes the job to run in the background, but EVOKE causes the called module to start immediately as a new job, while the procedure that EVOKEd the called module continues to run. There is no delay as there can be when JOBQ is called.