from a legal perspective, the term "s.m.a.r.t." refers only to a signalling method between internal disk drive electromechanical sensors and the host computer. hence, a drive may be claimed by its manufacturers to include s.m.a.r.t. support even if it does not include, say, a temperature sensor, which the customer might reasonably expect to be present. moreover, in the most extreme case, a disk manufacturer could, in theory, produce a drive which includes a sensor for just "one" physical attribute, and then legally advertise the product as "s.m.a.r.t. compatible".