//SORTIN DD DSNAME=INPUT,DISP=SHR

This example shows DD statement parameters that define a previously cataloged input data set:

DSNAME

causes the system to search the catalog for a data set with the name INPUT. When the data set is found, it is associated with the ddname SORTIN. The control program obtains the unit assignment and volume serial number from the catalog and, if the volume is not already mounted, writes a mounting message to the operator.

DISP

indicates that the data set existed before this job step, that it should be kept after this job step, and that it can be used concurrently by several jobs (SHR). None of the jobs should change the data set in any way.