Patent Number: 6,253,294

Title: Shared device access protection

Abstract: A method, system, and computer program product for protecting data of a shared access data storage system from being overwritten, where the data storage system includes a device which is shared by separate hosts over at least two logically or physically distinct communication paths. An overwrite protection facility operates the data storage system controller processor independently of the hosts to automatically protect the device upon the occurrence of a write command for the device. The protection allows only the communication path issuing the write command, and communication paths in the same group as the issuing communication path, to issue commands resulting in movement of the media on the device. Commands not resulting in movement of the media are allowed from any communication path. The protection continues until specifically released by a "MEDIA REMOVAL" command. The protection, in one embodiment, is by means of a prime protected attribute for the device-communication path pair. The protection permits normal initialization activities of attached hosts to occur without impediment, but blocks actions which could result in unintentional data overwrites (and data loss) in shared environments.

Inventors: Dahman; Kirby Grant (Tucson, AZ), Brogan, Jr.; James Jules (late of Pomerene, AZ), Brogan; by Irene (Pomerene, AZ)

Assignee: International Business Machines Corporation

International Classification: G06F 3/06 (20060101); G06F 012/00 ()

Expiration Date: 06/26/2018