Abstract: A warning against the possible failure is accurately sent from the magnetic disk device to a host device. In one embodiment, error indices per unit time are stored discontinuously/continuously for each magnetic head, and if the new index (partial integral error rate) updated with the stored multiple error indices as the items to be monitored satisfies required conditions, this state is diagnosed as an abnormality or a pseudo-abnormality, and reported to the host device. The partial integral error rate is updated with an increase in the number of sets of error indices. Each time a new set of error indices per unit time are stored, the oldest of the existing error indices to be monitored is discarded and one of the new error indexes is added. In this way, a new partial integral error rate is calculated from the fixed number of new sets of error indices to be monitored.

Abstract: A warning against the possible failure is accurately sent from the magnetic disk device to a host device. In one embodiment, error indices per unit time are stored discontinuously/continuously for each magnetic head, and if the new index (partial integral error rate) updated with the stored multiple error indices as the items to be monitored satisfies required conditions, this state is diagnosed as an abnormality or a pseudo-abnormality, and reported to the host device. The partial integral error rate is updated with an increase in the number of sets of error indices. Each time a new set of error indices per unit time are stored, the oldest of the existing error indices to be monitored is discarded and one of the new error indexes is added. In this way, a new partial integral error rate is calculated from the fixed number of new sets of error indices to be monitored.

Abstract: Heretofore, when an error occurs during data reproduction, a retry is repeated until the error is corrected, which leaves a possibility of data transfer being not completed within a specified time. Only one piece of error information on uncorrected errors is informed to a host system even if the errors have occurred in a plurality of unit data. To solve the problem, a magnetic disk drive is provided which can transfer data within a specified time because the number of retries executed when errors occur is limited to a range that data transfer can be finished within a specified time. The disk drive generates error information regarding all errors caused in reproduction and communicates error information along with reproduced data to a host system. The disk drive is capable of concurrent execution of data processing that allows of errors and data processing that does not allow of errors without demanding that the disk drive be furnished with high performance.

Abstract: A VTR capable of recording information signals, such as a time code, and more particularly providing a configuration for after-recording the information signals for controlling the operation of the VTR, which comprises an operation panel; a mode determination block for determining a mode to be next switched; an information signal processing block for recording and reproducing the information signals; and a recording period setting circuit for determining a recording period of the information signals. A mode signal inputted through the operation panel is recorded on a predetermined position on a magnetic tape. When such a magnetic tape is reproduced, the VTR is forcibly set in a mode determined by the mode signal at the time of detecting the mode signal.