central idea of UVC-based preservation is that digital objects preserved in an archive can be reconstructed anytime in the future without losing the meaning of that object. The UVC architecture is influenced by the characteristics as a real existing computer. It contains a memory, registers and a set of low-level instructions. The architecture differs from a 'real' computer in that it never has to be physically implemented. Consequently there are no actual physical cost. The core element of the UVC is its segment-based memory. It uses segments of memory to store distinct parts of the data. This segment-based design prevents the allocated memory to be accidentally overwritten by other applications as it does not share its memory space. Conceptual model Together with the original data it is possible to reconstruct the meaning of each particular digital object. The UVC can be seen as the heart of the system. Like the Java Virtual Machine and the Common Language Runtime, the UVC is actually an emulator which allows a program to run on virtual instances of the necessary, usually obsolete, hardware, and will continue to emulate the necessary hardware as technology continues to evolve. Because we do not know at this time which hardware is available in the future, the UVC must be created at the time we want to access a particular document from the repository. The UVC forms the platform on which programs specifically written for the UVC can run. What needs to be done Different steps must be taken at archiving time (present) and retrieval time (future). At archiving time Step 1 - Define the appropriate logical schema for a given application Step 2 - Choose an internal representation and associate a UVC program P with the data. This is part of the normal design of an application Step 3 – Write the UVC program for data interpretation Step 4 - Archive the schema information by storing an internal representation of the schema information in the bit stream together with a UVC program Q to decode it. Since the structure of the schema is the same for all applications, a schema to read schemata is chosen once and for all. At retrieval time Step 1 - Create an emulator on the current platform. Because of the simplicity of the UVC concept, it is fairly easy for skilled software developers to construct a UVC emulator for a particular platform of