On-line data archives

Digital libraries and other large archives of electronically retrievable and manipulable material are becoming widespread in both commercial and scientific arenas. Advances in networking technologies have led to a greater proliferation of wide area distributed data warehousing with associated data management challenges. We review tools and technologies for supporting distributed online data archives and explain our key concept of "active" data archives, in which data can be processed on-demand prior to delivery. We are developing wide-area data warehousing software infrastructure for geographically distributed archives of large scientific data sets, such as satellite image data, that are stored hierarchically on disk arrays and tape silos and are accessed by a variety of scientific and decision support applications. Interoperability is a major issue for distributed data archives and requires standards for server interfaces and metadata. We review present activities and our contributions in developing such standards for different application areas.