Abstract: A tape drive assembly for performing a backup operation has a tape receiving station to receive a data storage unit including a tape to store data in a data backup operation. A write head writes data to the tape in a data backup operation. A non-volatile memory unit records data in a data backup operation and communicates data to the write head. An input connected to a data host machine passes data to the memory unit such that, in use in a data backup operation, the data are communicated from the data host machine to the input and recorded in the memory unit prior to the data being passed from the memory unit to the write head for writing to the tape.

Abstract: A plurality of computers in a network each have a processor and a non-volatile data storage device such as a hard disk, a raid array, or the like. Each data storage device is divided into a first data storage area and a second data storage area. The first data storage area is reserved for use by at least one processor to which it is assigned, whereas the second data storage area is hidden from use by the file system of the computer, and is used to store replicated data of other ones of the plurality of computer entities. In the event of failure of any one of the data storage devices, data can be recovered from the second data storage areas of the other data storage devices.

Abstract: A plurality of computers in a network each have a processor and a non-volatile data storage device such as a hard disk, a raid array, or the like. Each data storage device is divided into a first data storage area and a second data storage area. The first data storage area is reserved for use by at least one processor to which it is assigned, whereas the second data storage area is hidden from use by the file system of the computer, and is used to store replicated data of other ones of the plurality of computer entities. In the event of failure of any one of the data storage devices, data can be recovered from the second data storage areas of the other data storage devices.

Abstract: A number of virtual areas with virtual addresses of storage locations within the virtual areas are allocated to a data storage array, having a total physical storage capacity. Physical addresses are allocated by an array controller for the disc storage array to the virtual addresses only as data are to be written to the respective virtual addresses.

Abstract: A data storage device has a non-volatile memory-storing data content, and a control processor for evaluating selected data content of the memory to establish whether there is a match between a characteristic of, or a derivative of, the data content and a reference data content characteristic, or derivative. The processor takes an action in response to the match.

Abstract: A sequence of data blocks written onto a medium of a data storage system includes first and subsequent appended data blocks having an append point code for identifying the first appended data block location. For data blocks having a running block number or frame number, the block or frame number of the first appended data block is stored as the append point code. The appended point code identifies the most recently append point location and aids in processes, such as tracking calibration, data integrity confirmation and track positioning.

Abstract: The availability of requested network resources in a network of servers, each having associated network-servable resources of a specific kind is maintained. Resource data and resource-serving application software serve out the resource data and dynamically distribute capacity to serve out servable resources between the resource servers dependent on demand for the resources. The capability of the network as a whole to serve out a particular resource dependent upon the level of demand for the particular resource is thereby varied. The capacity to serve out servable resources is distributed between the resources without necessarily moving the resource data itself between the servers by distributing: resource-serving application software and/or installation software adapted to install resource-serving application software.

Abstract: A demand on a server farm or local area network for a farm or network resource is satisfied. The farm or network has a demand director server, a first resource server having a first resource, and a second resource server having a second, different, resource. The director server is aware of what resources are held on the first and second resource servers. In response to a request for one of the first and second resources, one of the first and second resource servers is selected to serve out the requested resource and direct the request to the selected one of the first and second resource servers. The demand server selects an appropriate one of the resource servers to receive the request using its knowledge of where the requested resource is located.

Abstract: A method of serving out video over a network of video servers includes evaluating a capacity of the network as a whole to serve out specific video items by establishing, for each video server in the network, an established ability of each server to serve out the specific items that are potentially servable from each video server. The method further includes using the established abilities of each video server to evaluate an overall capability of the network as whole to serve out each of the specific video items. The method also includes varying the overall capability to serve out at least a selected one of the specific video items in accordance with the overall capability of the network.

Abstract: A tape is associated with a semiconductor memory storing the end position of the last data of a data set recorded on the tape. The end location is stored in the memory before the last data are written to the tape. In a further operation mode, data identifying the location of one or plural successfully written data sets which have already been written to the tape are stored in the memory while user data are written to the tape.

Abstract: In a digital data storage system providing two or more levels of interleaved Reed-Solomon error correction coding together with a track checksum, the track checksum is calculated according to an algorithm which has no correlation with the Reed-Solomon codeword generation rules. This allows miscorrections at the C2 correction level to be determined reliably thereby enhancing the correction rate. Also disclosed is a system which uses the enhanced ability to identify C2 miscorrections, to mark C2 miscorrections to the third level of error correction thereby allowing double error correct at the third level.

Abstract: In one embodiment, the present invention is directed to a system for managing a moveable media library. The system may comprise at least one robotic mechanics and a controller. The controller may comprise a processor for executing instructions and nonvolatile memory for storing at least: code for controlling the at least one robotic mechanics; and code for responding to commands received from host systems to retrieve a moveable medium of a plurality of moveable media, the code for responding is operable to receive the commands addressed with multiple device identifiers according to a device access protocol, and the code for responding is operable to associate each device identifier of the multiple device identifiers with at least one respective library partition.

Abstract: A sequence of data blocks written onto a medium of a data storage system includes first and subsequent appended data blocks having an append point code for identifying the first appended data block location. For data blocks having a running block number or frame number, the block or frame number of the first appended data block is stored as the append point code. The appended point code identifies the most recently append point location and aids in processes, such as tracking calibration, data integrity confirmation and track positioning.

Abstract: Utilisation by hosts of a data storage array is billed by allocating to the array a number of areas to which data can be written. A table of area usage is formed for each area. An area or areas are allocated to hosts as required. In response to data being written by a host to a sector of an area, a record of used sector is written to the respective table. On the basis of the information in the area usage tables, hosts are billed for the actual level of utilisation of the allocated area or areas.

Abstract: In a data storage system in which a sequence of data blocks is written onto a medium, appended data is distinguished by including in the first and subsequent appended data blocks an append point code uniquely identifying the location of the first appended data block. Where the data blocks have a running block number or frame number, the block or frame number of the first appended data block is stored as the append point code. This clearly identifies the most recent append point location which will aid in processes such as tracking calibration data integrity confirmation and track positioning.

Abstract: A management data distribution apparatus has, a control unit, a buffer memory element, at least one input port, and a telecommunications output. The at least one input port is arranged to receive management data from devices located within a network and to pass the management data to the control unit. The control unit is arranged to control output of the management data via the telecommunications output to a remote monitoring site over a telecommunications network. The control unit is also arranged to store management data arriving at the at least one input port when the said telecommunications output is in use in the buffer memory element, temporarily.

Abstract: A monitoring appliance for a data storage array used by plural hosts to store data responds to stored metadata to interrogate the data storage array at intervals to establish the amount of usage of the data storage array. Each host can use the file system(s) and/or database(s) of its choice in portions of the data storage array allocated to it. The monitoring appliance has basic knowledge of all file systems/databases used by the hosts, and the metadata structure of those file systems/databases.

Abstract: A number of virtual areas with virtual addresses of storage locations within the virtual areas are allocated to a data storage array, having a total physical storage capacity. Physical addresses are allocated by an array controller for the disc storage array to the virtual addresses only as data are to be written to the respective virtual addresses.

Abstract: A data storage device comprises a removable and replaceable magnetic tape cassette provided with a software control write protect switch. The switch is adapted to have a first condition in which data may be written to said magnetic tape and a second condition in which said switch is adapted to cause the blocking of a write operation to said tape. The switch is contained within a non-volatile electronic memory device and is electronically configurable between its first and second conditions remotely via a control signal.

Abstract: A tape drive assembly for performing a backup operation has a tape receiving station to receive a data storage unit including a tape to store data in a data backup operation. A write head writes data to the tape in a data backup operation. A non-volatile memory unit records data in a data backup operation and communicates data to the write head. An input connected to a data host machine passes data to the memory unit such that, in use in a data backup operation, the data are communicated from the data host machine to the input and recorded in the memory unit prior to the data being passed from the memory unit to the write head for writing to the tape.