Digi-data Corporation

William F Renner, Jr

This invention is a software-based method for facilitating the recovery of a RAID storage system from the simultaneous failure of two or more disks (catastrophic failure). It involves the identification of the logical address and length of the failed areas of the failed disks and the writing of this information into a bad region table which is replicated on each disk. This makes it easier and less expensive to identify the problem areas and make the necessary repairs.

Multiple-channel failure detection in raid systems

This invention provides a software-based method for determining the identity of a failed (hanging) channel in an array of multiple, buffered, synchronized data channels. A hanging channel may stem from a failed storage unit in the channel, a faulty connection within the channel, or a fault in the interface circuitry which connects the channel with the synchronization hardware. It is necessary and useful to identify a hanging channel in order to isolate it (as in a RAID 2-5 system) or for repair. The hanging channel is detected by examination of the byte content of the buffers. If the system is in a read mode, the buffer serving the hanging channel will contain substantially more bytes than the other buffers. If the system is in the write mode, the buffer serving the hanging channel will contain substantially fewer bytes than the other buffers.

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Baltimore, MD, United States of America

William F Renner, Jr