The present invention provides a user configurable computer interface for managing inventory. The applied drain voltage while sensing the data of one of the storage parts depends on the data stored at the other storage part. The bead seals on each side of a selected hole may be at different distances from the hole. The target may be in a container or under a surface. A method for updating the forgetting factor includes determining the gradient of the error signal, determining a value of the forgetting factor, and updating the value of the forgetting factor based on comparing the gradient of the error signal to the forgetting factor.