Means for maintaining the identification of defective minor loops in a magnetic bubble memory

A bubble domain memory system having a plurality of major/minor loop arrays suitable for the storage and guided movement of bubble domains, the system comprising:

• a plurality of minor loops in each of said arrays adapted for the storage of bits of data encoded as the presence or absence of bubble domains, said plurality of minor loops containing defective minor loops, a bit of data from the same position in each of said plurality of minor loops in each array represents a block of data,
• a plurality of pointers for said plurality of minor loops in each array that identify said defective loops,
• at least one block in each of said arrays reserved for the storage of said pointers, said pointer block and said data blocks containing a reserved portion as a notch means wherein the reserved portion includes a marker bit pattern to distinguish said the data from said data blocks, and
• a read-write memory system associated with said blocks and adapted to have the data from said blocks communicated to said read-write memory system during initialization wherein during the read/write operations of said bubble domain memory said read-write memory system enables the data positions to be skipped that correspond to said defective loops.