Output Produced by Dynamic Allocation

Certain data centers produce output using SVC99, or in other words, dynamic allocation. In these situations, there are no DD statements in the job’s JCL that represent the output. To have the output sent directly to CDAM, a modification in the dynamic allocation routine used in the data center is required to instruct the dynamic allocation routine to send the output to the CDAM subsystem instead of sending it to the system spool.

The problem that may arise when modifying the data center’s dynamic allocation program is that not all output produced by dynamic allocation should be sent directly to CDAM. This situation is especially obvious during the implementation process of Control-D. Control-D is usually implemented in stages. The implementation process does not take a long time, but it is still usually performed in stages.

A simple way of implementing the creation of output directly to CDAM when using dynamic allocation is to have the dynamic allocation program check if a specific DD statement appears in the job’s JCL. For example, the DD statement name can be CDAM and the DD statement could be a DD DUMMY statement. When a specific job (or job step) is required to produce output directly to CDAM, all that must be done is to add the special DD statement to the job’s JCL. The dynamic allocation program notices the special DD statement, and automatically perform the required modification. The required modification sends the output directly to the CDAM subsystem.

Using this method, the dynamic creation of output directly to CDAM can be on a job level (or even in specific job steps), while other output is sent to the system spool as before.