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 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: Techniques are described herein for returning a repository to a prior state. The repository may be, for example a database, and the prior state may be, for example the consistent state that the database had at a particular point in time in the past. When a operator-caused error has been introduced to the database by changes made by an already-committed transaction, the techniques described herein may be used to recover from the error by returning the database to a point in time prior to the commit time of the transaction that introduced the error. The techniques involve the generation of “physical undo” information, and the use of the physical undo information in conjunction with physiological undo and physiological redo to efficiently return a repository to the prior state.

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: 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: 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: Systems, methods and apparatus are provided through which in some embodiments, and database of images have categorized levels of severity of a disease or medical condition is generated from human designation of the severity. In some embodiments, the severity of a disease or medical condition is diagnosed by comparison of a patient image to images in the database. In some embodiments, changes in the severity of a disease or medical condition of a patient are measured by comparing a patient image to images in the database.

Abstract: Systems, methods and apparatus are provided through which in some embodiments, and database of images have categorized levels of severity of a disease or medical condition is generated from human designation of the severity. In some embodiments, the severity of a disease or medical condition is diagnosed by comparison of a patient image to images in the database. In some embodiments, changes in the severity of a disease or medical condition of a patient are measured by comparing a patient image to images in the database.

Abstract: Systems, methods and apparatus are provided through which in some embodiments, and database of images have categorized levels of severity of a disease or medical condition is generated from human designation of the severity. In some embodiments, the severity of a disease or medical condition is diagnosed by comparison of a patient image to images in the database. In some embodiments, changes in the severity of a disease or medical condition of a patient are measured by comparing a patient image to images in the database.

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 method, system, and program for allocating disk space and performance is disclosed. Stipples are interleaved throughout a disk to share space and performance characteristics.

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: A method for providing data integrity of a database system. A standby database is selected to replace a failed primary database. At least one redo log file having at least one data transaction is selected to be applied to the selected standby database. The selected standby database is updated with the data transaction from the selected redo log file if an identification code in the redo log file matches an identification code in the standby database.

Abstract: Pieces of data are stored among storage devices based on a cycle value, which is computed for each storage device as the total capacity of all storage devices divided by the individual capacity of the storage device. Next, a storage device for a current piece of data is selected to be the storage device with the smallest key value; followed by determination of a new key value based on at least (a) the cycle value and (b) a sequence number of the current piece. After allocation, if the number of storage devices changes, reallocation is done similarly except that selection is first from a preferred set and only if the preferred set is empty then from a remainder set. Storage devices are placed in the preferred set if a piece of data would be outside a shadow (based on cycle value) of another piece pre-existing in the storage device.

Abstract: A method and apparatus for creating a target database on a target platform based on a source database on a source platform is provided. A target database is created on the target platform based on data, metadata (for example, data in the system tablespace and control files), and external objects (for example, password files and externally stored tables) comprised within the source database. Data and metadata stored in tablespaces of the source database are converted to the format compatible with the target platform. The conversion of the data and metadata may be performed either at the source database or the target database. Redo information and undo information of the source database are not copied from the source database to the target database. Certain files, e.g., a password files, and links to externally stored object may be recreated on the target database.

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.