Describes an approximate document ranking process that uses a compact array of in-memory, low-precision approximations for document length. Combined with another rule for reducing the memory required by partial similarity accumulators, the approximation heuristic allows the ranking of large document collections using less than one byte of memory…

Describes the unique reliability problems of very large databases that necessitate specialized techniques for hardware problem management. The discussion covers the use of controlled partial redundancy to improve reliability, issues in operating systems and database management systems design, and the impact of disk technology on very large…

Presents an access method for temporal data called the Snapshot Index that reconstructs a past state of a time-evolving collection of objects. Previous approaches to temporal access methods are reviewed, and migrating data to write-once optical disks are discussed. (Author/LRW)

Discussion of local area networks and multiple file servers for concurrent information retrievals provides a rationale for workload and data allocation and presents an analytical model which will attain effective allocation policies. Nonlinear integer programming is discussed, and computational results show the effectiveness of the heuristic.…