A distributed model and algorithm for binary search

As part of the design of a roamer validation system for the cellular telecommunications industry, the authors consider parallel binary search techniques. They construct a hybrid parallel processing model by adding several dozen bytes of CRCW memory to a distributed memory system. A modified binary search algorithm for this model yields performance equal to that obtainable on a CRCW PRAM. The environment consists of a static sorted search list of 2ⁿ elements, and a distributed memory system with 2^p computers, where it is assumed for simplicity that p divides n. The authors use a modified divide and conquer approach, where the search list is distributed such that, for any current search interval, the left endpoint of each of the 2^p sub-intervals is contained in a separate computer. These endpoints are compared against the search key causing the incremental generation of the subscript corresponding to the search key. They build this subscript from the left, one base 2^p digit per cycle