CSDDISP

The CSDDISP parameter specifies the disposition of the data set to be allocated to the CSD.

CSDDISP={OLD|SHR}
If no JCL statement for the CSD exists when it is opened, the open is preceded by a dynamic allocation of the CSD using this disposition. If a DD statement exists in the JCL of the CICS startup job, it takes precedence over this disposition.
OLD
The disposition of the CSD is set to OLD if dynamic allocation is performed.
SHR
The disposition of the CSD is set to SHR if dynamic allocation is performed.

This parameter is effective only on a CICS cold or initial start. On a warm or emergency restart, file resource definitions for the CSD are recovered from the global catalog.