[摘录]发现一个经典的句子，层层套用。

The main idea of a memory hierarchy is that storage at one level serves as a cache for storage at the next lower level. Thus, the register file is a cache for the L1 cache, which is a cache for the L2 cache, which is a cache for the main memory, which is a cache for the disk. On some networked system with distributed file systems, the local disk serves as a cache for data stored on the disks of other systems.
这个句子层层套用，一共用了3个定语从句来解释原理。
恰恰有意思的是，此处解释的原理正是硬件存储结构的分层原理，不知道如此的句式是否有利于我们理解普遍存在于计算机科学中的分层原理呢。
哈哈，看到这里不禁会心一笑啊。