Abstract: An interface technology is disclosed by which an application program running on a host can invoke a command to cause a third party copy engine (“3PCE”) to carry out a desired copy operation without actually generating the command needed by the 3PCE. A first code arrangement is provided, receipt of which causes a processor to generate a second code arrangement representing a third party copy command and its corresponding parameters. Also, a liaison system and method are provided. The liaison system is interposed between an application program running on a host and a 3PCE external to the host. Such a liaison system comprises: an application program interface (“API”) to receive the first code arrangement (mentioned above); and a copy command generator to generate the second code arrangement representing the third party copy command and its corresponding parameters.