ABSTRACT TREEDUPL duplicates all directories and files in an MS-DOS directory tree rooted at some point to a directory tree rooted at some other point. If old versions of the files from the source directory tree are present in the target directory tree, they are replaced by the files from the source; if files in the target directory tree are not present in the source directory tree, the files in the target directory tree may optionally be deleted. In a DECnet-Rainbow or DECnet-DOS environment, TREEDUPL may be used to back up a local hard disk to a network virtual disk, and to restore the local hard disk from the network virtual disk.