Browse Prior Art Database

Multidimensional Dynamically Ordered Bubble Memory Store

IP.com Disclosure Number: IPCOM000080820D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 63K

Publishing Venue

IBM

Related People

Beausoleil, WF: AUTHOR [+2]

Abstract

U.S. Patent 3,766,534 which issued on October 16, 1973 to W.F. Beausoleil and B.E. Phelps describes a data storage unit, in which average and worst-case access times are significantly improved. The magnetic bubble memory implementation described herein can be advantageously used in that memory.

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Multidimensional Dynamically Ordered Bubble Memory Store

U.S. Patent 3,766,534 which issued on October 16, 1973 to W.F. Beausoleil and B.E. Phelps describes a data storage unit, in which average and worst-case access times are significantly improved.

The magnetic bubble memory implementation described herein can be advantageously used in that memory.

In the data storage, words of data including the word addresses are stored in groups of shiftable matrices. The groups of matrices are operable on a signal requesting access, to repetitively shift their contents to other matrix positions in various loops, some of which include a position from which a word may be accessed and some of which exclude the access position. The bits in a data word are distributed among groups of matrices, each group generally containing only one bit of a given word. Each group is logically divided into a plurality of sectors, with each sector containing bits from several words.

Controls are provided for varying the shifting in the various loops such that the positions of some or all of the sectors are dynamically reordered, so that the proximity of each of the sectors to the access position is approximately, or exactly, the order in which the sectors were last requested, and so that the word bits within the sectors are also positioned so that their proximity to the access position is approximately, or exactly, the order in which they were last requested. This reduces the average access time in programs involving considerable repeated reference to a limited group of sectors and/or words in the memory, and substantially reduces worst-case access time for all situations.

The figure shows a detailed layout of the magnetic structure. Bubble positions (small circles) are shown at the normal rest position 4 used when powering down or up; or other inactive periods. Control lines are normally not energized except for the Read/Write line which is normally energized.

Bubble labels A, B, C---indicate ordering wherein A is the most-recently used data and I the least-recently used. The left parallel register A,B,...is assumed to have a higher order than the right parallel register A1, B1, C1...

Assume that the data in position "C" is required for I/O. Two full counterclockwise (CCW) shifts will be taken to place C at bottom of the parallel registers.

When the desired C bubbles reach the position occupied by bubbles A in the figure, the regular clockwise (CW) or counterclockwise shift pattern will be ignored and a shift made from the original 4 direction directly to 2 moving all bubbles downward. Bubbles C and C1 will thus be moved out of the parallel regi...