Magnetic memory organization

DETAILED DESCRIPTION FIG.
1 shows a schematic diagram of an illustrative embodiment 10 of this invention.
The memory comprises a layer 11 of magnetic material in which magnetic bubbles can be moved.
Such a layer typically comprises a single cyrstal film of rare earth ions garnet grown epitaxially on a substrate of nonmagnetic garnet.
Amorphous layers of bubble material are also knwon in the art.
The movement of bubbles in layer 11 is determined by a pattern of magnetic elements which responds to a magnetic field which reorients in the plane of layer 11 in the illustrative field access type of bubble memory.
Representative ones of such elements are shown in FIG.
2.
In FIG.
1, the paths of bubble movement are represented by line diagrams characteristic of major/minor bubble organizations.
Block 13 represents a source of rotating field.
The major/minor organization characteristically includes a major loop into which bubble patterns are moved from permanent storage in an associated set of minor loops.
In FIG.
1, two major loops 20 and 21 are shown.
Each major loop has associated with it a minor loop 23 and 24 respectively.
The organization shown is intended primarily to make of an essentially square chip area.
As a general principle, the squarer the chip, the easier it is to handle.
The illustrative embodiment of the invention includes a bubble memory in which data is transferred to major loops 20 and 21 from the sets of minor loops in an operation similar to a familiar data swap.
The implementation of a transfer function in a magnetic bubble memory is disclosed, for example, in U.
S.
Pat.
No.
4,007,453, of the present invention issued Feb.
8, 1977.
The specific form of the implementation used in experimental circuits is shown in FIG.
2 and may be appreciated by those skilled in the art to be operative as a swap function.
As can be seen from the Figure, asymmetric mushroom-shaped elements define major loop 20 as represented by element 36.
An electrical conductor 50 overlies the permalloy elements (separated by a suitable insulating layer)