Magnetic Bubble Memory Architectures for Supporting Associative Searching of Relational Databases

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.