Memory Allocations for Multiprocessor Systems That Incorporate Content-Addressable Memories

For associative processing and relational data bases characterized by sequential memory search, it is convenient to store a sequence of data files in a content-addressable memory since it can perform two concurrent data base operations at a time (search and update, search and delete, etc.) and the sequential nature of its operation is in conformity with the sequential nature of maintenance and update of data files. To take into account various communication delays introduced by the communication network in transferring updated words to the content-adressable memory assume that a sequence of data words contained in the same data file is stored with a shifting distance from one another, d ¿ 1, where the d integer is selectable by a programmer, and a pair of adjacent data words from the same file may have a constant or variable d. (A particular case, d = 1, means consecutive word storage.) In this paper, we discuss various memory allocation algorithms that allow formation of a multiprocessor system that incorporates several content-addressable memories and is designated for fast data base applications. All memory allocation schemes introduced in this paper are described by a Diophantine equation whose solution, x, shows the distance between any two processors that are not in conflict when they access the same content-addressable memory. The paper presents a technique for finding a maximal set of noninterfering processors and conflict-free allocation techniques for various structures of data files.