Fault Tolerance:Redundancy 提高MTTF:避免，容忍，预测 -故障“难以消除(eliminate),只能掩盖(mask) 。 容错计算系统：出现一定限度的失效时，依然能够提供所 需要的服务. 一服务降级：使之不影响系统的正常使用 冗余 Information redundancy Eg,a Hamming code can be added to transmitted data to recover from noise on the tansmission line. Time redundancy is especially helpful for transient or intermittent faults. ·Eg,using transactions(▣滚，rollback) Physical redundancy Eg,747s have four engines but can fly on three ·RAID 容错能力：检错（发现，定位），纠错Fault Tolerance：Redundancy • 提高MTTF：避免，容忍，预测 – 故障“难以消除（eliminate），只能掩盖（mask）” • 容错计算系统：出现一定限度的失效时，依然能够提供所 需要的服务. – 服务降级：使之不影响系统的正常使用 • 冗余 – Information redundancy • Eg, a Hamming code can be added to transmitted data to recover from noise on the tansmission line. – Time redundancy • is especially helpful for transient or intermittent faults. • Eg, using transactions(回滚，rollback) – Physical redundancy • Eg, 747s have four engines but can fly on three • RAID • 容错能力：检错（发现，定位），纠错