Abstract: Systems, methodologies, components, and other embodiments associated with controlling access to a storage device are described. One example system embodiment comprises an access controller configured to control access requests to the storage device by metering access to data within a first region within the storage device and by allowing unmetered access to data within a second region within the storage device.

Abstract: An approach for efficiently managing logical volumes of data includes subdividing logical volumes of data into relatively small pieces that are spread over several physical disks. When a determination is made that a particular disk drive is to store more than one piece of a volume, a plurality of pieces of the volume are selected to be stored on the particular disk drive based at least in part on how far apart the pieces are within an address space of the volume. In response to an addition of one or more new drives to a system that contains a plurality of disk drives, at least a piece of each of the plurality of volumes may be moved from a drive of the plurality of disk drives to at least one of the one or more new drives.

Abstract: A method and mechanism for implementing variable sized extents for a logical volume or file is disclosed. Instead of using extents which all have the same size to form a logical volume, a logical volume includes extents having different extent sizes. A relatively small extent size is used for extents allocated for the first portion of a logical volume, which increases to a larger extent size for extents allocated to a second portion of the logical volume, which again increase one or more times for extents allocated for later portions of the logical volume.

Abstract: Techniques are provided for managing caches in a system with multiple caches that may contain different copies of the same data item. Specifically, techniques are provided for coordinating the write-to-disk operations performed on such data items to ensure that older versions of the data item are not written over newer versions, and to reduce the amount of processing required to recover after a failure. Various approaches are provided in which a master is used to coordinate with the multiple caches to cause a data item to be written to persistent storage. Techniques are also provided for managing checkpoints associated with the caches, where the checkpoints are used to determine the position at which to begin processing recovery logs in the event of a failure.

Abstract: Methods are provided for communicating with and regulating access to a storage system contained within a file system. Storage access keys are used to communicate to the file system changes in location of data stored in the storage system. Fence keys are used to regulate access to the storage system.

Abstract: An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated.

Abstract: A high voltage electrode and method of construction is provided including a multi-layered composition to optimize dielectric strength, dielectric constant, structural strength and durability. The high voltage electrode can be utilized as a submergible drop-in unit for easy installation within a fluid holding tank such as a water cooling tower. The submergible generator includes a channel that houses a charged electrode, and functions as a ground electrode to the charged electrode, and also functions as a fluid diverter.

Abstract: A system and method for managing storage from multiple data storage devices are disclosed. The system and method provide improved load balancing, reduction or elimination of fragmentation, and efficient changes in hardware configurations. I/O load and data are spread relatively evenly across many data storage devices in the storage system. Dynamic reorganization can be performed for the data stored on the data storage devices.

Abstract: Methods are provided for communicating with and regulating access to a storage system contained within a file system. Storage access keys are used to communicate to the file system changes in location of data stored in the storage system. Fence keys are used to regulate access to the storage system.

Abstract: An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated.

Abstract: A packaging system (1) includes a telescoping platform assembly (100) having a guide mount (30) and an extension platform (40). The packaging system (1) incorporating the telescoping platform assembly (100) includes a panel (22) and a flap member (26). The flap member (26) is connected to the panel (22) along a pivot axis (27) and is adapted to move between a first position with respect to the panel (22) and a second position with respect to the panel (22). The guide mount (30) includes a guide mount slot (33) whereas the flap member (26) includes a flap guide slot (28) extending outwardly from the pivot axis (27) through the flap member (26). The extension platform (40) is mounted on the guide mount (30) and the flap member (26) and is adapted to slide between a stowed position and a deployed position along guide mount slot (33) and the flap guide slot (28).

Abstract: Methods are provided for communicating with and regulating access to a storage system contained within a file system. Storage access keys are used to communicate to the file system changes in location of data stored in the storage system. Fence keys are used to regulate access to the storage system.

Abstract: A system and method for managing storage from multiple data storage devices are disclosed. The system and method provide improved load balancing, reduction or elimination of fragmentation, improved redundancy schemes, and efficient changes in hardware configurations. Redundancy methods are employed to prevent loss of data from an occurrence of a multiple disk failure.

Abstract: A system and method for managing storage from multiple data storage devices are disclosed. The system and method provide improved load balancing, reduction or elimination of fragmentation, and efficient changes in hardware configurations. I/O load and data are spread relatively evenly across many data storage devices in the storage system. Dynamic reorganization can be performed for the data stored on the data storage devices.

Abstract: A method and apparatus for managing access to resources is provided. When a process requires access to a resource, the process requests a lock on the resource from a lock manager unit that resides on the same node as the process. If a resource object for the resource does not exists, one is created in the lock manager unit, but not on lock manager units on other nodes. Because each lock manager unit does not have to store all resource objects, and resource objects are only created for resources that are actually used, the overhead of the lock management system is significantly reduced. Resources are grouped in recovery domains. When a lock manager unit that supported a recovery domain fails, the recovery domain is marked invalid. All resources in the recovery domain are considered invalid unless it would have been impossible for a failed instance to have held an exclusive lock on the resource. A snapshot of lock information is made before cleanup is performed on invalid resources.

Abstract: A packaging device (1) including a flap retention arrangement (30). The packaging device incorporating the flap retention arrangement (30) includes a panel (22) and a flap member (26). The flap member (26) is connected to the panel (22) and adapted to move between a first position and a second position with respect to the panel (22). The flap retention arrangement (30) includes a retention member (33) and a capture element (37). The retention member (33) is mounted on one of the flap member (26) or the panel (22) while the capture element (37) is located on the other one of the flap member (26) or the panel (22). Regardless of which portion of the flap retention arrangement (30) is mounted on one of the flap member (26) or the panel (22), the retention member (33) and the capture element (37) are situated so as to make contact with each other when the flap member (26) is moved to the second position. This contact retains the flap member (26) in the second position.

Abstract: An apparatus and method for accessing a data item from a storage system having a plurality of data storage devices are disclosed. I/O operation requests are submitted to multiple data storage devices for each data item to be accessed. The I/O operation requests are issued to copies of the data items that reside on a plurality of data storage devices. More I/O operation requests are submitted than the number of data items that are to be accessed, written, or updated.

Abstract: Every node in a multi-node parallel database system maintains a logical clock for generating timestamps. The logical clocks are synchronized by attaching a current timestamp to every message that is sent by a node. When a node receives an incoming timestamp that is greater than the value indicated by the associated logical clock, it sets the associated logical clock forward to at least the value of the timestamp. Each node continually sends and receives a message including a timestamp at least once in a prescribed period of time. Moreover, each node maintains a high watermark that represents a time greater or equal to the highest time of any logical clock in the multi-node parallel database system.

Abstract: A method and apparatus identifies backup files that will restore a file in a transactional system. A reset stamp and filename is used to identify all backup files of the file having the filename since the file was last restored. A smaller number of files necessary to restore the file are selected from these backup files by sorting the list of files and selecting certain files in sort order. If necessary, earlier reset stamps are identified and more files are identified and selected, until a file is selected that contains a full backup or datafile copy of the file. For the backup files selected, information such as the location of the file is stored in the order in which the backup files are selected. The information, such as the location of each file selected, is provided in an order that is the reverse of the order in which the files were selected so that the oldest file is listed first. The files may be restored in the order provided.

Abstract: A system and method backs up computer files to backup drives connected to multiple computer systems. Each file in a backup set is allocated to one or more backup subsets for each of the multiple computer systems. The files can be allocated in an even number across each subset, allocated to evenly spread the number of bytes to each subset, or, using the capacity of each of the multiple computer systems, allocated so that each computer system can complete backing up the files allocated to it in approximately the same amount of time. The system can restrict the number of bytes continuously required from a single disk by one of the backup machines from exceeding a threshold limit. Each of the multiple computer systems is then directed to, and the computer systems do, back up files in one or more subsets, which may be allocated to that computer system.