Interchangeable magnetic bubble memory

An interchangeable magnetic bubble memory device having first and second interchangeable memory bubbles, each of the modules including a magnetic bubble memory having at least one major loop or non-recirculating track, each major loop or track including a plurality of minor loops for storing magnetic bubbles. There are no more than n defective minor loop locations indicated by an error map. A detector produces data signals indicating the presence or absence of magnetic bubbles in the minor loops and a microprocessor provides control signals for controlling the transfer of the data signals between the data memory and the microprocessor. A driver is included and is responsive to the enable control signals from the microprocessor for transferring, replicating, generating and/or destroying the bubbles with low power consumption. A control store is provided for storing error map instructions for encoding the error map such that the modules can be interchanged regardless of the locations of the defective minor loops in each of the modules.