Abstract: A server federation cooperatively interacts to fulfill service requests by communicating using data structures that follow a schema in which the meaning of the communicated data is implied by the schema. Thus, in addition to the data being communicated, the meaning of the data is also communication allowing for intelligent decisions and inferences to be made based on the meaning of the data. Cooperative interaction is facilitated over a wide variety of networks by messaging through a common API that supports multiple transport mechanisms. Also, mid-session transfer between client devices is facilitated by schema and the transport-independent messaging structure. The user interfaces of the client devices will appear consistent even if the client devices have different user interface capabilities.

Abstract: Various embodiments of the present invention are directed to a storage platform comprising a database engine, a data store, an application programming interface. The data store is implemented on the database engine for storing data therein, and the data store implements a data model that supports the organization, searching, sharing, synchronization, and security of data stored in the data store. Specific types of data are described in schemas. The application programming interface enables application programs to access services and capabilities of the storage platform and to access the data described in the schemas. The storage platform supports interoperability with existing file systems, enables users and systems to synchronize data stored in different instances of the data store, and provides the ability for application programs to be notified about and to track changes made to the data in the data store.

Abstract: Each node in a data processing system contains at least one undo buffer and one least one redo buffer for insuring that any changes made to a section of a non-volatile storage medium, such as a disk, can be removed, if a transaction has not been committed, or can be recreated if the transaction has not been committed. The undo buffers each correspond to a different uncommitted transaction. The redo buffer contains the changes made to a copy of the section which is maintained in the memory.

Abstract: A data processing system maintains logs for system and media recovery. The logs contain state identifiers each uniquely identifying the state of a corresponding section of a storage medium, such as a disk. The state identifiers are assigned after changes have been made such that they can be determined from the information in the logs. One implementation involves assigning state identifiers in a known sequence, such as in a monotonically increasing sequence of integers beginning with zero.

Abstract: In a transaction processing system, snapshot records are stored in volatile memory along with volatile state memory records, and modifications to the volatile state memory records by the transactions are logged to an after-image log in non-volatile memory for recovery of the volatile state memory records. For recovery of the snapshot records in volatile memory, when any one of the records of volatile state memory are to be written from volatile memory to non-volatile state memory, the volatile snapshots records of the volatile state memory record are first written from volatile snapshot memory to non-volatile snapshot memory. This ordering of buffer pool flushing permits recovery of the volatile snapshot records from non-volatile state memory or from modifications in the after-image log. Moreover, recovery can be performed without writing modifications to the volatile snapshot records in an after-image log or flushing the snapshot records using an atomic operation.