Patent ID: 7934067

Claim:
A data update history storage apparatus that stores update data, the apparatus comprising: a buffer pool that temporarily stores the update data; a page management unit that sets authorized access for each buffer address for buffer data stored in the buffer pool; an address management unit that manages the correlation between a buffer address where the update data is stored in the buffer pool and a data area address where the relevant update data is stored; an I/O (input/output) command catcher that changes, when an I/O command is issued in order to store arbitrary update data in a data area address corresponding to a buffer address storing the arbitrary update data, the authorized access that has been set for the arbitrary update data in the page management unit to be readable; and a page exception catcher that issues a page exception report when the authorized access set for the arbitrary update data is changed to readable, acquires the data area address corresponding to the buffer address that stores the arbitrary update data from the address management unit, and stores the update data and an update history of the update data in an update queue.