Browse Prior Art Database

Quick Exit Path Feature for Magnetic Bubble Memories

IP.com Disclosure Number: IPCOM000052826D
Original Publication Date: 1981-Jul-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 57K

Publishing Venue

IBM

Related People

Rosenfeld, JL: AUTHOR

Abstract

A magnetic bubble memory is described having a major/minor loop configuration wherein the readout loop is divided into segments which each end in a switch to provide control paths for diverting the bubbles out of the active area.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Quick Exit Path Feature for Magnetic Bubble Memories

A magnetic bubble memory is described having a major/minor loop configuration wherein the readout loop is divided into segments which each end in a switch to provide control paths for diverting the bubbles out of the active area.

In a conventional major/minor loop magnetic bubble organization, when a record (or line) is read, bubbles are transferred from the minor loops to the major readout loop and shifted along this to a detector. The transfer may be performed by replicating bubbles from the minor loops onto the readout loop. Even if only part of the record is of interest, all bubbles in the readout loop must be propagated past the last minor loop (to be detected and then destroyed) before another read operation may be performed, since bubbles cannot be transferred into the readout loop while other bubbles occupy space there.

The present magnetic bubble organization divides the readout loop into s segments. Each segment ends with a switch. When the switches are in the normal position, the bubbles propagate normally along the readout loop from segment to segment, and from the last segment to the detector. When the switches are in the ``dump'' position, the bubbles are diverted to paths that lead out of the active array area. These switches are activated in parallel after the useful information has been sensed. The control unit is responsible for returning the switches to their normal positions after all bubbles have been diverted to the paths leading out of the active area. Thus, after desired data from the readout loop have been detected, the rest of the bubbles in the readout loop may be diverted out of the active area. Another read operation into the empty readout loop can occur as soon as the s segments are empty. The extra cycles to propagate all bubbles past the last minor loop are not required. If s is a large number, the segments are small, and the number of cycles required to empty the segments is also small.

Fig. 1 shows a part of a magnetic bubble memory with a conventional major/minor loop organization. When it is desired to read the record at the tops of the minor loops 10, the replicate line 12 is pulsed, which causes all bubbles at the tops of the minor loop 10 to be replicated onto the readout loop 14. During the following memory cycles, they are propagated along the readout loop to the detector (not shown). A second read operation cannot be performed until all bubbles have been propagated beyond the...