Abstract: The invention is about a modular system for filing, automatically selecting and playing digital disks infinitely expandable in all the three dimensions with a corresponding increase in the number of digital disks filed. A microcomputer (PC) controls the servomechanisms utilized by the system to move around the digital disks, with the use of information files describing the stored digital disks contents and the system topology. The system can be expanded by adding an infinite number of three basic structural unit modules in all the three dimensions and updating the system information files at the same time. In such a system the user stores each digital disk once and, after that, uses his information records, by manipulating the related data base, to form selection sequence files to be played. The user can customize the system according to his/her needs either by increasing its storage capacity or by modifying its topology.