The PARALLEL command initiates parallel task scheduling wherein multiple tasks are processed concurrently. When you use parallel processing, commands may not process in the order in which they appear in the input stream. The PARALLEL command is effective only when the required system resources (virtual storage, DASD, or tape volumes) are available. If there are resource conflicts (multiple tasks that use the same DASD or the same tape volume) or if there is not enough virtual storage that is available for all of the tasks to run concurrently, some tasks can be delayed until the resources are available (other tasks end).

DFSMSdss attempts to delay the initiation of additional tasks if there are insufficient available resources to initiate the tasks. DFSMSdss is not able to accurately assess which additional resources that a task might later require. If you attempt to run too many tasks in parallel for the available resources, it can result in unpredictable failures. In such cases, the user must establish a safe upper boundary on the number of tasks that can be supported as parallel tasks.

>>-PARallel----------------------------------------------------><