A spinal correction system includes at least one longitudinal element extending between a first portion and a second portion. A magnetic recording media made by forming at least a magnetic coat and an overcoat on a substrate of non-magnetic magnetic disk on which surface a liquid lubricant having a structure of perfluoropolyether is coated, wherein average roughness of overcoat surface Ra is less than 0. The encoding employs modulo arithmetic. These vectors may contain elements that indicate one or more actions performed involving other objects.