Magnetic bubble memory having by-pass paths for defective loops

摘要

A magnetic memory of the type storing information in the form of the presence or absence of magnetic domains at specified locations therein. The manufacturing yield of such memories is improved by providing alternate paths in a transfer loop to allow domains in the transfer loop to by-pass defective ones of a plurality of memory loops. The normal path in the transfer loop carries a domain past the entrance of all successive memory loops. Alternate paths are provided from the entrance of a memory loop subsequent to the successively positioned memory loop. If the successively positioned memory loop is defective, a semi-permanently stored domain is entered into a postion which effectively places the alternate path into the transfer loop and effectively removes a normal path from the transfer loop.