Abstract: The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns.

Abstract: The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns.

Abstract: A device including an array of aligned conductive channels. The conductive channels are operable for directional transport of species selected from the group consisting of electrons, ions, phonons, and combinations thereof. The conductive channels are provided for by nanofibers in a form selected from the group consisting of ribbons, sheets, yarns, and combinations thereof.

Abstract: The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns.

Abstract: Managing a multi-version data record database is provided. A mapping is maintained between a logical record identifier and committed and uncommitted physical record identifiers corresponding to data records using an indirection mapping table. Entries are updated within an index to point to the logical record identifier instead of the committed and uncommitted physical record identifiers. The committed physical record identifier corresponding to a data record is read from the indirection mapping table to access a committed version of the data record while a writer is modifying the data record to prevent the writer from blocking a reader. An uncommitted physical record identifier corresponding to the data record is written in the indirection mapping table to insert a new uncommitted version of the data record within a data table while the reader is reading the committed version of the particular data record to prevent the reader from blocking the writer.

Abstract: Methods and a system are provided. A method includes maintaining an in-page log for records in each of a plurality of data pages of a multi-version database. The method further includes adding record update information to the in-page log when a corresponding one of the records is deleted or updated. The method also includes consulting the in-page log for a recently updated one of the records or a recently deleted one of the records to determine a record status thereof. The method additionally includes spilling, by a processor-based overflow manager, to overflow pages when the in-page log is full. The data pages include any of row-oriented data pages and column-oriented data pages.

Abstract: Methods and a system are provided. A method includes maintaining an in-page log for records in each of a plurality of data pages of a multi-version database. The method further includes adding record update information to the in-page log when a corresponding one of the records is deleted or updated. The method also includes consulting the in-page log for a recently updated one of the records or a recently deleted one of the records to determine a record status thereof. The method additionally includes spilling, by a processor-based overflow manager, to overflow pages when the in-page log is full. The data pages include any of row-oriented data pages and column-oriented data pages.

Abstract: Managing a multi-version database is provided. A logical record identifier to physical record row identifier indirection mapping table on a solid-state storage device is extended to include a plurality of delta blocks. A delta block within the plurality of delta blocks is maintained for each primary key in a plurality of primary keys associated with a data table on a magnetic hard disk storage device.

Abstract: Fabricating a nanofiber ribbon or sheet with a process that includes providing a primary assembly by arranging carbon nanotube nanofibers in aligned arrays, the arrays having a degree of inter-fiber connectivity, drawing the carbon nanotube nanofibers from the primary assembly into a sheet or ribbon, and depositing the sheet or ribbon on a substrate.

Abstract: A system and method for adjusting space allocated for different page sizes on a recording medium includes dividing the recording medium into multiple blocks such that a block size of the multiple blocks supports a largest page size, and such that each of the multiple blocks is used for a single page size, and assigning an incoming page to a block based on a temperature of the incoming page.

Abstract: Managing a multi-version database is provided. A logical record identifier to physical record row identifier indirection mapping table on a solid-state storage device is extended to include a plurality of delta blocks. A delta block within the plurality of delta blocks is maintained for each primary key in a plurality of primary keys associated with a data table on a magnetic hard disk storage device.

Abstract: Managing different versions of a data record is provided. A mapping is maintained between a version-independent logical record identifier and a version-dependent physical record row identifier that correspond to each data record within a plurality of data records of a data table using a logical record identifier to physical record row identifier indirection mapping table. Entries within leaf pages of an index associated with the data table are updated to point to the version-independent logical record identifier corresponding to a data record instead of pointing to the version-dependent physical record row identifier corresponding to the data record. The logical record identifier to physical record row identifier indirection mapping table is updated in response to performing an operation on the data record instead of updating the entries within the leaf pages of the index associated with the data table.

Abstract: Methods and systems for performing database transactions include executing a first transaction request in a preplay mode that locks the requested data with a prefetch-lock and reads one or more requested data items from storage into a main memory buffer; locking the requested data items with a read/write lock after said data items are read into the main memory buffer; and performing the requested transaction on the data items in the main memory buffer using a processor.

Abstract: The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and IJV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns.

Abstract: Managing different versions of a data record is provided. A mapping is maintained between a version-independent logical record identifier and a version-dependent physical record row identifier that correspond to each data record within a plurality of data records of a data table using a logical record identifier to physical record row identifier indirection mapping table. Entries within leaf pages of an index associated with the data table are updated to point to the version-independent logical record identifier corresponding to a data record instead of pointing to the version-dependent physical record row identifier corresponding to the data record. The logical record identifier to physical record row identifier indirection mapping table is updated in response to performing an operation on the data record instead of updating the entries within the leaf pages of the index associated with the data table.

Abstract: The present invention is directed to nanofiber yarns, ribbons, and sheets; to methods of making said yarns, ribbons, and sheets; and to applications of said yarns, ribbons, and sheets. In some embodiments, the nanotube yarns, ribbons, and sheets comprise carbon nanotubes. Particularly, such carbon nanotube yarns of the present invention provide unique properties and property combinations such as extreme toughness, resistance to failure at knots, high electrical and thermal conductivities, high absorption of energy that occurs reversibly, up to 13% strain-to-failure compared with the few percent strain-to-failure of other fibers with similar toughness, very high resistance to creep, retention of strength even when heated in air at 450° C. for one hour, and very high radiation and UV resistance, even when irradiated in air. Furthermore these nanotube yarns can be spun as one micron diameter yarns and plied at will to make two-fold, four-fold, and higher fold yarns.

Abstract: Managing a multi-version data record database is provided. A mapping is maintained between a logical record identifier and committed and uncommitted physical record identifiers corresponding to data records using an indirection mapping table. Entries are updated within an index to point to the logical record identifier instead of the committed and uncommitted physical record identifiers. The committed physical record identifier corresponding to a data record is read from the indirection mapping table to access a committed version of the data record while a writer is modifying the data record to prevent the writer from blocking a reader. An uncommitted physical record identifier corresponding to the data record is written in the indirection mapping table to insert a new uncommitted version of the data record within a data table while the reader is reading the committed version of the particular data record to prevent the reader from blocking the writer.

Abstract: A system and method for adjusting space allocated for different page sizes on a recording medium includes dividing the recording medium into multiple blocks such that a block size of the multiple blocks supports a largest page size, and such that each of the multiple blocks is used for a single page size, and assigning an incoming page to a block based on a temperature of the incoming page.

Abstract: Staging data record changes from a faster storage medium to a slower storage medium using data query rewriting is provided. In response to receiving a data query corresponding to a particular data record, it is determined whether the data query is one of a transactional data query or an analytical data query. In response to determining that the data query is a transactional data query, the transactional data query is rewritten to apply transactional delta changes to the particular data record on a storage-class memory of a computer. In response to determining that the data query is an analytical data query, the analytical data query is rewritten to select and reconcile each data record corresponding to the particular data record stored on the storage-class memory with the particular data record stored on a persistent data storage device of the computer.

Abstract: Staging data record changes from a faster storage medium to a slower storage medium using data query rewriting is provided. In response to receiving a data query corresponding to a particular data record, it is determined whether the data query is one of a transactional data query or an analytical data query. In response to determining that the data query is a transactional data query, the transactional data query is rewritten to apply transactional delta changes to the particular data record on a storage-class memory of a computer. In response to determining that the data query is an analytical data query, the analytical data query is rewritten to select and reconcile each data record corresponding to the particular data record stored on the storage-class memory with the particular data record stored on a persistent data storage device of the computer.