Abstract: A method for identifying cell coupling in a memory system includes generating a two-dimensional pseudorandom binary sequence array. The method also includes performing an erase operation on a plurality of cells of a memory block of the memory system. The method also includes performing a write operation on the plurality of cells using the two-dimensional pseudorandom binary sequence array. The method also includes performing a read operation on the plurality of cells to identify a voltage value for each cell of the plurality of cells. The method also includes identifying cell coupling between respective cells of the plurality of cells using the voltage value for each of the cells of the plurality of cells.

Abstract: A disk drive is disclosed having a disk, and a head actuated over the disk, the head comprising a magnetoresistive (MR) element. Control circuitry within the disk drive sets an operating bias current for the MR element by computing a target voltage for the MR element, applying a bias current to the MR element, measuring a voltage across the MR element corresponding to the bias current, and adjusting the bias current applied to the MR element until the measured voltage substantially equals the target voltage.

Abstract: A method is disclosed for setting an operating bias current for a magnetoresistive (MR) element. A bias current is applied to the MR element, and a voltage across the MR element is measured corresponding to the bias current. The bias current is then adjusted in response to the bias current multiplied by a ratio of a target voltage and the measured voltage. The adjusted bias current is then applied to the MR element. In one embodiment, the bias current is adjusted until the measured voltage substantially equals the target voltage.

Abstract: A disk drive is disclosed comprising a disk having top and bottom surfaces, and top and bottom heads actuated over the top and bottom surfaces, respectively. Control circuitry detects a warping of the disk by writing a first test pattern to the top surface, reading the first test pattern to generate a first read signal, monitoring a first read signal value proportional to an amplitude of the first read signal, writing a second test pattern to the bottom surface, reading the second test pattern to generate a second read signal, monitoring a second read signal value proportional to an amplitude of the second read signal, and processing the first and second read signal values to detect a negative correlation between the amplitudes of the first and second read signals.