23. Assume a disk subsystem with the following components and MTTF: - 10 disks, each rated at 1,000,000-hour MTTF - 1 ATA controller, 500,000-hour MTTF - 1 power supply, 200,000-hour MTTF - 1 fan, 200,000-hour MTTF - 1 ATA cable, 1,000,000-hour MTTF Assume that the failures are independent. We add one redundant power supply and one redundant fan to the system. By adding these two redundant components, the system becomes 8000 times more reliable. What is the improvement for the overall system