Browse Prior Art Database

Structure to Allow Redundancy in a Bubble Memory

IP.com Disclosure Number: IPCOM000080199D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Chang, H: AUTHOR

Abstract

In magnetic bubble domain systems, redundant shift registers are provided on the chip which are normally not selected because the selection current loops in their decoding lines are shorted. When a shift register in the main array is found defective, its selection current-loop pattern is duplicated in a replacement shift register by burning off the short circuits in its decoding line. Thus, there is no need for a memory to keep record of bad shift registers and their replacement.

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Structure to Allow Redundancy in a Bubble Memory

In magnetic bubble domain systems, redundant shift registers are provided on the chip which are normally not selected because the selection current loops in their decoding lines are shorted. When a shift register in the main array is found defective, its selection current-loop pattern is duplicated in a replacement shift register by burning off the short circuits in its decoding line. Thus, there is no need for a memory to keep record of bad shift registers and their replacement.

A structure which allows redundancy in a magnetic bubble memory is illustrated. The output of all shift registers are tied together by a common connector. The selection of a shift register for readout is done by a decoder (not shown in the figure). Through a common connector, the delay between the time a shift register is selected for readout and the time the signal appears at the detector will be the same for all shift registers, thus eliminating any extra accommodation when a defective shift register is replaced. References 1. Chang, et al., "Self-Contained Magnetic Bubble Domain Memory Chip", IEEE Trans. on Mag., June 1972. 2. Bobeck, A Chevron Propagator/Expander, Electrochemical Society Meeting, Houston, Texas, May 1972.

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