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Browse Prior Art Database

Multidimensional Dynamically Ordered Bubble Memory Store

IP.com Disclosure Number: IPCOM000080821D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 4 page(s) / 54K

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 magnetic bubble memory shown in the drawing contains no separate distinct I/O register. Instead, during I/O operations the bottom bubble positions of all main (parallel) registers are: switched out of the main registers and combined to form an independent I/O register. It comprises a set of a number of main shift registers arranged in parallel on a magnetic bubble chip. (There may be more than one set on a chip.) Data in the main registers is ordered by most recent use. During search operations, the bubbles move around the main registers as described in the IBM Technical Disclosure Bulletin, Vol. 16, No. 9, February 1974, Pages 2973 to 2975.

When the desired data (bubble positions) are in the bottom position of the main registers, the bottom positions may be effectively disconnected from the main registers and caused to act together as an I/O register by the proper energization of a control line (Separation Control). With this (Separation) control line energized, the main registers function as before except that they are one position shorter. Bubbles in the I/O register formed from the bottom positions of the main registers, can now be read out, and reordered and rewritten if and as required. When the I/O operation is complete, reordering of the main registers may be accomplished. De-energi...