the time Step 2 - Develop a Logical Data Viewer (a restore program to restore the data). This is an application program that reads the UVC object code and the bit stream and invokes the emulator to execute the UVC program i.e. the program controls the UVC and all input/output interaction between it Step 3 - Write a restore program to restore the schema. Since the logical view for the schema information is fixed a single restore program may actually support all applications. If the future client already knows the logical view for the documents being restored then the schema does not necessarily needs retrieving. Furthermore, the schema only needs to be requested once for a collection of documents of the same type UVC convention The UVC convention includes the information items that need to be archived today, and preserved indefinitely to enable the retrieval of digital objects in the future. Included in the convention are; The UVC architecture document The interface to the UVC emulator (Logical Data Viewer) The definition of the logical data schema or LDS (the schema to read schemata) The convention must be 'written in stone'. It can be saved digitally, on paper and/or in micrographic media. Preservation System Components UVC-based preservation as the central idea of the UVC-based preservation method is based on four different components. These are: UVC program (format decoder) Logical data Schema (LDS) with information type description Universal Virtual Computer Logical data viewer (UVC interface) UVC interpreter Restoration program Fig. 2 UVC and its components Description of method The UVC program decodes the file format of a digital object. This format decoder program runs on the UVC, which is the platform-independent layer, independent of future hard- and software changes. Executing the format decoder delivers the element tags. These elements build the Logical Data View (LDV) of the data, which is quite similar to XML. The LDV is an instantiation of the LDS, describing the structure and meaning of the tags as parts of a specific information type. All these components are controlled by a Logical Data Viewer simply called viewer. For reconstruction, the viewer starts the UVC and feeds it with the data of the digital object to a format decoder running on top of the UVC. In return it retrieves an LDV and reconstructs a specific representation of the original object’s meaning. Performance The architecture relies on concepts that have existed