Abstract: A data replication system is disclosed in which replication functionalities between a host computer, an interconnecting computer network, and a plurality of storage devices are separated into host elements and a plurality of storage elements. The host computer is connected to one or more host elements. The host element is responsible for replicating data between the storage devices, which are each connected to an associated storage element, and for maintaining data consistency. Further, the host element instructs a storage element whose associated storage device does not contain up-to-date data to recover from another one of the plurality of storage elements and its associated storage device. The storage elements and their associated storage devices may be located in any combination of diverse or same geographical sites in a manner to ensure sufficient replication in the event of a site or equipment failure.

Abstract: A data replication system is disclosed in which replication functionalities between a host computer, an interconnecting computer network, and a plurality of storage devices are separated into host elements and a plurality of storage elements. The host computer is connected to one or more host elements. The host element is responsible for replicating data between the storage devices, which are each connected to an associated storage element, and for maintaining data consistency. Further, the host element instructs a storage element whose associated storage device does not contain up-to-date data to recover from another one of the plurality of storage elements and its associated storage device. The storage elements and their associated storage devices may be located in any combination of diverse or same geographical sites in a manner to ensure sufficient replication in the event of a site or equipment failure.

Abstract: The present invention is an apparatus for generating random bits from a computer system. The apparatus comprises a rotating storage device operating within the computer system. A rotational latency of the rotating storage device is associated with the computer system accessing information from the storage device with the rotational latency causing the accessing of the information to have an entropy. An extraction mechanism extracts random bits derived from entropy of the rotational latency of the storage device.

Abstract: A system for scheduling read-requests for a serpentine data tape. The transit time between arbitrarily selected locations in the tape is not a linear function of distance between the locations. Despite this non-linearity, a model has been developed which accurately predicts such transit times. Using the model, a list of read-requests is re-organized into a sequence requiring a minimal, or at least smaller, total time to execute.