If you are opening an existing file, most file systems linked into the run-time system will be searched for the named file. If, however, you are creating a new file, you will need to tell the run-time system which file system to use. You accomplish this with the following ACUFH configuration variable:
DEFAULT_HOST filesystem
This variable will designate the file system to be used for newly created files that are not individually assigned. If this variable is not given a value, the EXTFH file system is used.
Examples
DEFAULT_HOST DB2
means that all new files will be DB2 files unless individually assigned to another file system.
DEFAULT_HOST ORACLE
means that all new files will be Oracle files unless individually assigned to another file system.