Direct measurement of magnetoresistive head resistance in a storage system

A computer-implemented method, comprising:

• in a first AC mode:
• measuring a reference voltage across a reference resistance while applying a reference AC current to the reference resistance to generate an AC reference voltage signal across the reference resistance;
• measuring a second voltage across a magnetoresistive (MR) head while applying a second AC current to the MR head to generate a second AC voltage signal across the MR head wherein the second AC current has a known proportionality to the reference AC current;
• and
• calculating the MR head resistance as a function of a ratio of the measured second voltage to the measured reference voltage.

A computer system, comprising:

• a storage system having a storage drive having magnetoresistive (MR) heads;
• a host coupled to the storage system;
• a processor of at least one component of the computer system;
• and
• a computer program product for measuring resistance of an MR head of the storage system, wherein the computer program product comprises a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause operations, the operations comprising:
• in a first AC mode:
• measuring a reference voltage across a reference resistance while applying a reference AC current to the reference resistance to generate an AC reference voltage signal across the reference resistance;
• measuring a second voltage across an MR head while applying a second AC current to the MR head to generate a second AC voltage signal across the MR head wherein the second AC current has a known proportionality to the reference AC current;
• and
• calculating the MR head resistance as a function of a ratio of the measured second voltage to the measured reference voltage.