Abstract: A magnetic bubble memory device with major/minor loops includes at least one boot loop and a plurality of minor loops. Data stored in the boot loop in the form of bubbles are controlled by the reading out of the data independently from the minor loops. Header data are stored in the boot loop. Faulty loop data of the minor loops are stored in the minor loops with a certain positional relationship based on the header data. This results in allowing the device to be applied to a memory having a larger capacity, a higher production yield, and a high-speed detection time for faulty loop data.

Abstract: Disclosed herein is a method of testing a magnetic bubble device which guarantees allowable variation ranges for a variety of signal components of input signals applied to a magnetic bubble element when the magnetic bubble device is to be energized. A variety of signal components are varied in a testing cycle for writing, reading and collating information, whereby a plurality of combinations of the variety of signal components are obtained. The obtained input signals are continuously applied to the bubble element to effect the test.