The following describes data control block fields containing information that defines the data characteristics and device requirements for a data set. Each of the fields described shows the values that result from specifying various options in the DCB macro. These fields can be referred to by the problem program by a DCBD macro that creates a dummy control section (DSECT) for the data control block. Fields that contain addresses are 4 bytes long and are aligned on a fullword boundary. If the problem program inserts an address into a field, the address must be inserted into the low-order 3 bytes of the field without changing the high-order byte.
The contents of some fields in the data control block depend on the device and access method being used. A separate description is provided when the contents of the field are not common to all device types and access methods.
For diagnosis purposes, z/OS DFSMSdfp Diagnosis describes more fields.