Long-term preservation of complex processes

A sequence of bits ingested, say, in 2005, is meaningless in 2055 if it cannot be interpreted at that time to produce the same essential information that was available to a 2005 user. Such an interpretation requires a program (a format interpreter). In a method initially proposed in Refs. I through 3, the format interpreter is written, in 2005, for a Universal Virtual Computer (UVC) that can be easily emulated in the future. A current implementation of the UVC exists and interpreters have been written for a variety of formats including JPEG and GIF, and (partially) Excel, Lotus 1-2-3, and PDF. However, these applications only handle static features of the formats and do not involve general interaction with the outside world. The purpose of this paper is to show how the UVC method can preserve more complex objects by exploiting its communication facility (between the UVC program and a new 2055 application). If the format interpreter needs some input, it communicates with the new application program which interacts with the outside world in a way en vogue in the future. Since the new application can receive parameters from the user and transfer them to the UVC program, the latter can compute new results, therefore supporting dynamic objects. To capitalize on the fact that the whole functionality of the original application can potentially be executed on the UVC, it is important to think about how existing code can be transferred to the UVC with a minimal effort. The involvement of format owners may be the key to success.