Abstract: Embodiments of the invention relate to diagnosing error-correcting retries of an upper system by using a disk drive under control of the upper system. In one embodiment, a microprocessor can operate in any of at least two operation modes. One is normal operation mode while the other is pseudo failure operation mode. Mode switching is made by a switch. Strictly, the pseudo failure operation mode includes three different operation modes: 1) pseudo logical error report mode in which a pseudo logical error is reported to the upper system without performing disk control; 2) pseudo component circuit failure mode in which a control circuit is forced to cause a failure by setting invalid control values to the control circuits; and 3) pseudo interface failure mode in which a pseudo interface failure in the system comprising multiple disk drives is reported by setting an invalid control value to the interface control circuit.

Abstract: Embodiments of the invention relate to diagnosing error-correcting retries of an upper system by using a disk drive under control of the upper system. In one embodiment, a microprocessor can operate in any of at leas two operation modes. One is normal operation mode while the other is pseudo failure operation mode. Mode switching is made by a switch. Strictly, the pseudo failure operation mode includes three different operation modes: 1) pseudo logical error report mode in which a pseudo logical error is reported to the upper system without performing disk control; 2) pseudo component circuit failure mode in which a control circuit is forced to cause a failure by setting invalid control values to the control circuits; and 3) pseudo interface failure mode in which a pseudo interface failure in the system comprising multiple disk drives is reported by setting an invalid control value to the interface control circuit.