When the application program is opening an existing file or creating a new file, you need to tell the runtime which file system to use. You accomplish this with one of two configuration variables: DEFAULT_HOST or filename_HOST.

DEFAULT_HOST filesystem

designates the file system to be used for files that are not individually assigned. If this variable is not given a value, and if you have not individually assigned a file system (with filename_HOST), the Vision file system is used.

Note: The DEFAULT_IDX_FILESYSTEM variable is a synonym for DEFAULT_HOST.