A data communication system for distributing music data files between a server and a client removably connected to the server. The system transfers music data files and corresponding management data from a client to a server. The server then determines whether the music data files were previously stored in the server on the basis of the corresponding management data transferred from the client and a management data file in the server. If it is determined that the music data files were previously stored in the server, the music data files transferred from the client are stored into their previous locations in the server. In this manner, the music data files may be repeatedly moved to and from the server and maintain their ordering on the server.