International Business Machines Corporation

Harold Glen Slone

William Frank Micka

Larry Richard Perry

Harry M Yudenfriend

Jeffrey Mark Nick

David B Petersen

Gregory E McBride

Gail Andrea Spear

David Michael Shackelford

Robert Frederic Kern

Gavin Stuart Johnson

Ronald Maynard Kern

Douglas Michael Zobre

Robert Vaughn Geiner

Luis Ricardo Urbanejo

Christopher John Hinrichs

A method for sending a message from one host () to at least one other host, both of which are attached to a hardware subsystem () that is bidirectionally coupled to a mass data storage unit () includes (a) transferring a Send Message command through a channel () from a first attached host to the hardware subsystem, the Send Message command having at least one second attached host as an intended recipient; (b) buffering () at least a message payload portion of the Send Message command at the hardware subsystem and generating an unsolicited interrupt in the at least one second attached host; and (c) in response to the unsolicited interrupt, transferring a Request Message command through a channel from the at least one second attached host to the hardware subsystem for obtaining at least the message payload portion buffered at the hardware subsystem. The Send Message command may be a point-to-point message having a single other attached host as an intended recipient, or it may be a point-to-multipoint message having a plurality of other attached hosts as intended recipients. The hardware subsystem need have no knowledge of the message contents sent between hosts.

Method and apparatus using attached hardware subsystem to communicate between attached hosts

An apparatus, system, and storage medium are disclosed for utilizing data protection by a storage device to minimize loss of sensitive data on a storage medium. The apparatus includes a monitor module, a verification module, and a process module. The monitor module recognizes a write-type command from a host connected to an electronic data storage device. The verification module determines a presence of a passkey associated with the write-type command. The process module processes the write-type command according to the determination of the presence of the passkey. The apparatus, system, and storage medium provide protection of sensitive data at the device level so that a designated protected area on the electronic data storage device is protected against an inadvertent data overlay.

Apparatus, system, and storage medium for data protection by a storage device

In a system including a host, a primary storage subsystem coupled to the host, a cache coupled to the host and separate from the primary storage system, a secondary storage subsystem, and a data mover coupling the primary and secondary storage systems, data is temporarily cached for future storage in the primary storage subsystem so as to preserve timestamp information and maintain data consistency for asynchronously mirroring the data at a secondary subsystem.

Adjusting timestamps to preserve update timing information for cached data objects

A database management system ensures consistency between primary and mirrored backup copies of a database, despite occurrence of a suspending condition interrupting the normal process of mirroring the primary database. One or more primary controllers are provided, each having a data storage unit with multiple primary data storage devices. Multiple secondary controllers each have multiple associated secondary data storage devices, each secondary controller being coupled to one primary controller. One or more primary databases reside on the primary devices, with a corresponding number of secondary databases residing on the secondary devices. Each secondary database mirrors a corresponding primary database. Either a host, attached to a primary controller, or one of the primary controllers itself, maintains a map cross-referencing each primary and secondary database with the primary and secondary devices containing portions thereof. If a predefined &ldquo;suspending condition&rdquo; affecting data mirroring occurs, the host or primary controller consults its map to identify all primary and secondary devices affected by the condition. Then, each primary controller stops all ongoing and future read/writes with each of its affected primary devices. Each primary controller also directs each secondary controller having an affected secondary device to stop mirroring the primary databases stored on that device. Then, the primary controller starts intermediate change recording and resumes read/writes with its primary devices. When the suspending condition ends, each primary controller applies the appropriate logged changes to its secondary database(s) and then reactivates each secondary database.

Database backup system ensuring consistency between primary and mirrored backup database copies despite backup interruption

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Los Gatos, CA, United States of America

Harold Glen Slone