这个缓存层通过将数据保留一段时间(或者随即预先读取数据以便在需要是就可用)优化了对物理设备的访问。
This caching layer optimizes access to the physical devices by keeping data around for a short time (or speculatively read ahead so that the data is available when needed).
根据一段时间运行试验数据可优化某些故障判据，逐渐完善系统。
The malfunction criterions of some parts can be improved by more experiment data to improve the whole system.
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