You should keep these considerations in mind for existing Query/38 applications.
Existing Query/38 applications, if they are to query remote files, must be re-created in all cases, even if the target server is an iSeries™ server or a System/38™. If the target server is an iSeries server or a System/38, the re-created application that uses a DDM file is defined and run as if the remote file is a local file. The optimization feature can be used to get the records from the target iSeries server or the target System/38.