To create DAM files, areas to be used as the DAM files must be allocated with damload command or a UAP that handles offline work. The name to be used for this allocation must be the pathname of the character type special file allocated as the OpenTP1 file system. The file identified by this pathname is referred to as the physical file and the file name is referred to as the physical file name. The physical file name is used when creating initial data in the allocated DAM file and updating the contents of the file in an offline environment.

When DAM files are used from SUPs, SPPs, or MHPs in online mode, the logical files given names in the system definition are accessed. These files are referred to as logical files and their names are referred to as logical file names. Logical and physical file names are in one-to-one correspondence. This correspondence is specified in the DAM service definition.

Since logical and physical files are defined at each node, DAM files are managed at each node independently of other nodes. This means that UAPs cannot use DAM files located at other nodes. To use DAM files, a UAP process in the node (machine) must access the files with the file names defined in the node.