DATA STORAGE METHOD AND QUEUING METHOD

摘要

PURPOSE: To provide a set of large capacity storing devices collectively functioning as one or more logical large capacity storage devices. CONSTITUTION: Comand queuing on the input/output controller of the parity drive of RAID levels 4 or 5 decides the logical block addresses of data drive and the parity drive in response to the reception of a writing instruction with additional data. When a parity cache entry coincides with a parity address, a cache hit is generated. In response to the cache hit, exchange parity data is calculated from parity data read existing at the position of a cache provided from the parity cache entry, data read from a data drive and additional data and newly calculated parity data are arranged in the cache. In order to write the exchange parity data next, a command is transmitted to the input/output controller of a drive in which the pavity data are arranged.