a method and apparatus to manage files of a portable device such as an mp3 player , a mobile phone , or a game console , the method comprising copying files to be played from a source server and storing the files in a file system on a folder - by - folder basis ; determining the presence of files which have been changed in the portable device by checking the file system when the files are completely copied ; and creating a playlist of the files , folder - by - folder , according to file path information of the file system when there are the changed files .