Abstract: Distributing and redistributing records among a changing set of storage devices is accomplished by grouping the records based on the starting and ending numbers of storage devices.

Abstract: Systems and methods for managing data within a networked computer environment including application servers and a plurality of storage devices utilize a collection of service modules, each separately addressable from and in communication with the application servers and the storage devices and providing system-wide services to the application servers and the storage devices.

Abstract: A multi-version database system controls visibility of data during transaction processing. A transaction includes a transaction identifier that identifies the transaction and an invisibility list of transactions whose effects are invisible to the transaction. Changes made by other transactions are visible to the transaction based on the isolation level of the transaction. Records are visible to a transaction based on a creator identifier stored in the record that identifies the transaction that created the record.

Abstract: A mechanism controls concurrency among database transactions through the use of serial ordering relations. The ordering relations are computed dynamically in response to patterns of use. An embodiment of the present invention serializes a transaction that accesses a resource before a transaction that modifies the resource, even if the accessor starts after the modifier starts or commits after the modifier commits. A method of concurrency control for a database transaction in a distributed database system stores an intended use of a database system resource by the database transaction in a serialization graph. A serialization ordering is asserted between the database transaction and other database transactions based on the intended use of the database system resource by the database transaction. The serialization ordering is then communicated to a node in the distributed database system that needs to know the serialization ordering to perform concurrency control.

Abstract: A mechanism controls concurrency among database transactions through the use of serial ordering relations. The ordering relations are computed dynamically in response to patterns of use. An embodiment of the present invention serializes a transaction that accesses a resource before a transaction that modifies the resource, even if the accessor starts after the modifier starts or commits after the modifier commits. A method of concurrency control for a database transaction in a distributed database system stores an intended use of a database system resource by the database transaction in a serialization graph. A serialization ordering is asserted between the database transaction and other database transactions based on the intended use of the database system resource by the database transaction. The serialization ordering is then communicated to a node in the distributed database system that needs to know the serialization ordering to perform concurrency control.

Abstract: A disk is segmented into a first data segment and a secondary data segment. The secondary data segment stores a logical mirror of the first data segment of another disk. Fast access to data stored on the disk is provided by partitioning the disk such that the first data segment includes the fast tracks of the disk and the secondary data segment includes the slow tracks of the disk and forwarding all data requests to the first data segment. Upon detecting a failure, the logical mirror of data stored in the first data segment of the failed disk is accessible from the secondary data segment of a non-failed disk. The first data segment can be rebuilt quickly on another disk from the logical mirror stored in the secondary data segment.

Abstract: A multi-version database system controls visibility of data during transaction processing. A transaction includes a transaction identifier that identifies the transaction and an invisibility list of transactions whose effects are invisible to the transaction. Changes made by other transactions are visible to the transaction based on the isolation level of the transaction. Records are visible to a transaction based on a creator identifier stored in the record that identifies the transaction that created the record.

Abstract: A disk is segmented into a first data segment and a secondary data segment. The secondary data segment stores a logical mirror of the first data segment of another disk. Fast access to data stored on the disk is provided by partitioning the disk such that the first data segment includes the fast tracks of the disk and the secondary data segment includes the slow tracks of the disk and forwarding all data requests to the first data segment. Upon detecting a failure, the logical mirror of data stored in the first data segment of the failed disk is accessible from the secondary data segment of a non-failed disk. The first data segment can be rebuilt quickly on another disk from the logical mirror stored in the secondary data segment.

Abstract: A mechanism controls concurrency among database transactions through the use of serial ordering relations. The ordering relations are computed dynamically in response to patterns of use. An embodiment of the present invention serializes a transaction that accesses a resource before a transaction that modifies the resource, even if the accessor starts after the modifier starts or commits after the modifier commits. A method of concurrency control for a database transaction in a distributed database system stores an intended use of a database system resource by the database transaction in a serialization graph. A serialization ordering is asserted between the database transaction and other database transactions based on the intended use of the database system resource by the database transaction. The serialization ordering is then communicated to a node in the distributed database system that needs to know the serialization ordering to perform concurrency control.

Abstract: A mechanism controls concurrency among database transactions through the use of serial ordering relations. The ordering relations are computed dynamically in response to patterns of use. An embodiment of the present invention serializes a transaction that accesses a resource before a transaction that modifies the resource, even if the accessor starts after the modifier starts or commits after the modifier commits. A method of concurrency control for a database transaction in a distributed database system stores an intended use of a database system resource by the database transaction in a serialization graph. A serialization ordering is asserted between the database transaction and other database transactions based on the intended use of the database system resource by the database transaction. The serialization ordering is then communicated to a node in the distributed database system that needs to know the serialization ordering to perform concurrency control.

Abstract: The invention concerns a novel chemical process for the manufacture of methyl (2S)-2-[3R)-3-(N-[tert-butyloxycarbonyl]amino)-2-oxopyrrolidin-1-yl]propionate.

Abstract: A method and apparatus for accessing and effectively integrating non-object oriented data stores with object applications. An integrating environment is implemented wherein an application using a distributed object database and object database management system (ODBMS) is provided with an interface to external data stores in a manner so as to effect location transparency. The application, accessing data via the ODBMS, can manipulate data in foreign data stores which include external data that is mapped and converted into objects for use by object applications. A storage management application program interface ("SM API"), effects a functional interface for handling objects, referencing objects, implementing iteration and indexing of objects, and implementing object transaction and cache handling.

Abstract: A system for generating globally unique identifiers for objects in a distributed object oriented database. In one embodiment the system comprises at least two processors connected by means of a network to a processor executing a server process which provides globally unique identifiers for objects throughout the network. Each processor on the network may execute one or more client processes, each of which may run transactions against the database. Each such client process transmits a request to the server process which provides the globally unique identifiers when that client process requires a globally unique object identifier for objects which the requesting client process is creating. In response to the request, the server which provides globally unique identifiers transmits a range of globally unique object identifiers to the requesting client process. The requesting client process then allocates object identifiers from this range of globally unique object identifiers to the objects it is creating.

Abstract: A device (10) and a method for positioning a rotatable printing cylinder (16) for a printing press (12). A drive (24) can rotate the cylinder (16) about a cylinder axis (52) at relatively high and low speeds. A sensor (68) is positioned adjacent to the cylinder (16) for detecting rotational positions of the cylinder (16) and providing a signal which varies in response to detected rotational positions of the cylinder (16). A sensor exciting target (66) has first and second edges (74 and 76) at first and second ends, respectively, of a sector of the cylinder (16). The sensor (68) is aligned with the first edge (74) at a first rotational position of the cylinder (16) and is aligned with the second edge (76) at a second rotational position of the cylinder (16).