| 摘要 |
An XOR controller which is capable of performing the XOR operations necessary to generate a new parity value corresponding to new data being written to a disk storage device from a host computer without the intervention of the storage subsystem microprocessor. In one embodiment the storage subsystem microprocessor controls the loading of the new data from the host and old data and parity from a disk storage device into cache memory, if such data is not already in cache memory, and creates the appropriate data structures. The storage subsystem microprocessor then loads the XOR controller with a pointer to a table in cache memory containing information needed by the XOR controller to perform the XOR operations. The XOR controller, upon completion of the XOR operations on all the data, informs the storage subsystem microprocessor of such completion. Thereafter, the microprocessor causes the new data and new parity to be written to the disk storage device from the cache memory. |
