1. A method for implementing a directory structure of a host system, comprising: a plurality of basic computing units interconnecting to construct a system computing unit set; wherein each of the basic computing units comprises a protocol processing chip and a system resource management firmware; dividing a part implementing a logic function in the protocol processing chip into a static part and a dynamic part in advance, wherein the dynamic part can be reconstructed; constructing a system cache directory storage architecture through the dynamic part; the method further comprising: when a cache directory is stored with a system internal storage, configuring the dynamic part into a high-capacity on-chip memory to cache the cache directory, and when the cache directory is stored with a local double data rate synchronous random access memory (DDR), configuring the dynamic part into a plurality of memory controllers to access the cache directory stored in the local DDR.