Issue No. 11 - November (1980 vol. 29)
K.L. Doty , Department of Electrical Engineering, University of Florida
A memory organized around a major/minor loop magnetic bubble storage unit contains database information in relational form. An external marker memory, consisting of an M-bit shift register or an M X 1 RAM, provides, in conjunction with an assumed processing element, an associative search capability. Each bit accumulates search results of a query applied to its corresponding bubble page. The number of pages M equals the minor loop length and N, the page size, equals the number of minor loops in the bubble memory. A systematic series of performance-improving access strategies and architectural modifications are applied to an existing major/minor loop bubble device to determine the effects of each change. In all cases data access-time formulas reveal that positioning a marked page for access is a linear function of the minor loop length M, while outputting the marked pages via the bubbles serial output bus is a quadratic function of M. An evaluation and relative comparison of these architectures indicate that a segmented, nondestructive major/minor loop transfer function can enhance current magnetic bubble memory (MBM) performance in relational data processing by an order of magnitude.
search time, Associative retrieval, associative search, information retrieval, magnetic bubbles, major/minor loops, memory architectures, memory-scan, query, relational database
J. Greenblatt, K. Doty and n. Stanley Y.W. Su, "Magnetic Bubble Memory Architectures for Supporting Associative Searching of Relational Databases," in IEEE Transactions on Computers, vol. 29, no. , pp. 957-970, 1980.