DBH-specific files are session-related files which the DBH creates and which are permanently associated with just that DBH.
The default ID for DBH-specific files is the same as the startup ID for the DBH. The system administrator, however, can ensure that DBH-specific files other than the cursor files are created under a different ID. In this event, he/she must assign the appropriate link names to the files before starting the DBH.
The media catalog
The DBH's media catalog contains storage information for the following DBH-specific files:
the transaction log files (2 TA-LOG files)
the restart log file (WA-LOG file)
the cursor files
The media catalog describes the volumes on which these files are to be stored, as well as the catalog IDs under which they are to be stored, and the storage statements used to store them.
The information in the media catalog is only evaluated if a file has not already been created at the start of the session.
The DBH-specific files are only created on the specified medium if they are not already located on a different medium at the start of the session.
System administrators create the media catalog with the DBH option MEDIA CATALOG. The media catalog does not exist in the form of a file. It is only valid for the duration of a DBH session and is maintained in the DBH's memory.