Final answer:
The mean time to failure of a mirrored disk depends on both the mean time to failure of individual disks and the mean time to repair, as both factors contribute to the overall reliability and recovery capability of the mirrored disk setup.
Step-by-step explanation:
The mean time to failure of a mirrored disk depends on both, the mean time to failure of individual disks and the mean time to repair. A mirrored disk setup, commonly known as RAID 1, is designed to provide fault tolerance by writing the same data onto two separate disks. This means that if one disk fails, the system can continue to operate using the second disk.
The mean time to failure of individual disks is a measure of how long a disk is expected to operate before experiencing a failure. Therefore, the reliability of each disk will directly impact the overall reliability of the mirrored setup. If one disk fails, the system continues to rely on the remaining operational disk until the failed one is replaced or repaired.
The mean time to repair is also a critical factor as it determines how quickly a failed disk can be brought back to operation, restoring the full redundancy of the mirrored setup. The shorter the repair time, the less time the system operates with a single disk, and hence, the lower the chance of a second disk failure leading to data loss.
So, the correct answer to the question is c) Both I and II, as the mean time to failure of a mirrored disk does indeed depend on both the reliability of the individual disks and how swiftly they can be repaired after a failure.