A mechatronic system is a synergistic integration of mechanical, electrical, electronic and software technologies into electromechanical systems. Unfortunately, mechanical, electrical, and software data are often handled in separate Product Data Management (PDM) systems with no automated sharing of data between them or links between their data. Presently, this is a significant drawback with regard to supporting the collaborative and integrated design of mechatronic systems. One underlying research question to be addressed is: “ How can such domain-specific PDM systems be integrated and what are the standards needed for this?” Our starting point for addressing this question is to look into how engineering data is stored today. We believe that the more intelligent and sophisticated the mechanisms for file management are, the more Computer-aided Engineering systems will benefit from them in terms of making integrated cross-disciplinary product development more efficient. However, while Computer-Aided Design and Engineering (CAD/CAE) systems and related tools such as, for example, Product Data Management (PDM), Engineering Data Management (EDM), etc. have significantly matured over the past ten years, most of their associated database systems are still based on traditional file systems and hierarchical directory structures. In light of this context, we will initially discuss a number of disadvantages of current file management systems. In the body of the paper our main contribution is presented. That is, a formal mathematical model of a new semantic file system, SIL ( Semantics Instead of Location), that allows engineers to access data based on semantic information rather than storage location is proposed. A major difference between our approach and previous related work is that we do not aim at yet another point solution and, instead, propose an approach that may be employed by next generation engineering data processing systems on a larger scale. In addition, a corresponding programming interface along with a graphical user interface used as a file browser is presented and the benefits of utilizing the proposed semantic file system for product data management in the field of integrated design of mechatronic systems are discussed.