Abstract: A storage controller and associated disk or disk portion where after the controller terminates its access to said disk or disk portion, data integrity problems in the disk or disk portion can be detected. Before host data associated with a write command is written from the cache memory to the disk or disk portion, an identity of the storage controller as a current user of the disk or disk portion and indication that the controller is operating in a mode it stores data in a cache is recorded on the disk or disk portion. If the storage controller is shut down abnormally, the record of the identity of the controller and the indication are not cleared. The storage controller is restarted or rebooted and the record is read to learn that the controller was using the disk or disk portion and operating in the foregoing mode before the shutdown.

Abstract: A method for operating a storage controller and associated disk or disk portion such that after the storage controller terminates its access to said disk or disk portion, data integrity problems in the disk or disk portion can be detected. The storage controller is coupled to one or more host computers to receive write commands to write host data onto the disk or disk portion. The storage controller receives a write command from the host and writes host data associated with the write command into a cache memory in the storage controller. Before the host data is written from the cache memory to the disk or disk portion, the following is recorded on the disk or disk portion—an identity of the storage controller as a current user of the disk or disk portion and an indication that the storage controller is operating in a mode in which it stores data in a cache before writing the data to the disk or disk portion.