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Bubble Memory Storage and Encoding

IP.com Disclosure Number: IPCOM000079328D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR [+2]

Abstract

Conventional bubble domain storage arrays employ uniformly spaced bit positions. Moreover, if the spacing between bubble positions is allowed to vary, then the amount of data stored in a given area can be increased. For example, in an "Angel Fish" device, under the restriction that two adjacent bubbles must be spaced apart by at least three triangles, eight triangles can accommodate thirteen possible word patterns with variable spacing, while fixed spacing can only accommodate less than eight patterns.

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Bubble Memory Storage and Encoding

Conventional bubble domain storage arrays employ uniformly spaced bit positions. Moreover, if the spacing between bubble positions is allowed to vary, then the amount of data stored in a given area can be increased. For example, in an "Angel Fish" device, under the restriction that two adjacent bubbles must be spaced apart by at least three triangles, eight triangles can accommodate thirteen possible word patterns with variable spacing, while fixed spacing can only accommodate less than eight patterns.

In one coding scheme, four data bits are stored for a group of eight triangles. The first seven positions of the triangles represent data, whereas the eighth position is used to provide the necessary minimum distance between bubbles at word boundaries. In a specific case, whenever two words are linked in the bubble shift register such that the pattern of the first word has a bubble in position 7, and the pattern of the second word has a bubble in position 1, then those two bubbles are replaced by a single bubble in position 8 of the first word.

The figure shows the bubble patterns representing a series of four data bits.

In another approach, the length of a triangle may be made half of the diameter of a bubble, rather than equal to the diameter of a bubble. In such case, the minimum number of triangles between the bubbles is established at four. As a result, data storage density is increased. Further reductions in size of the tria...