A No-Compromises Architecture for Digital Document Preservation

The Multivalent Document Model offers a practical, proven, no-compromises architecture for preserving digital documents of potentially any data format. We have implemented from scratch such complex and currently important formats as PDF and HTML, as well as older formats including scanned paper, UNIX manual pages, TeX DVI, and Apple II AppleWorks word processing. The architecture, stable since its definition in 1997, extends easily to additional document formats, defines a cross-format document tree data structure that fully captures semantics and layout, supports full expression of a format's often idiosyncratic concepts and behavior, enables sharing of functionality across formats thus reducing implementation effort, can introduce new functionality such as hyperlinks and annotation to older formats that cannot express them, and provides a single interface (API) across all formats. Multivalent contrasts sharply with emulation and conversion, and advances Lorie's Universal Virtual Computer with high-level architecture and extensive implementation.