Patent ID: 6934877
Filing Date: 2005-08-23
Classification: G06F

Abstract:
1. A data backup and recovery system for computers ,comprising: blocks storing sequentially records containing a single unique key and zero or one or more non-unique keys; a primary system that controls the location of these blocks by means of a location table pairing the blocks with physical addresses in random access memory and manages a database or databases stored in random access memory; and a secondary system or systems that is provided with backup blocks corresponding to the blocks of the said primary system in which the source data is stored, controls the location of these blocks by means of a location table pairing the blocks with physical addresses in random access memory, and manages a database or databases stored in random access memory, wherein said primary system transmits to the secondary system or systems the content of updated data and information, specifying the blocks where updated content, data and pre-updated information is stored, said secondary system or systems are provided with a synchronous tightly-coupled or an asynchronous loosely-coupled sequencing system arranged to receive transaction initiation information from said primary system and then receive log completion information to said primary system after receiving transaction completion information from the primary system until that backup update processing is complete, and when a transaction is canceled or suffers abnormal termination and the primary system receives a message that the transaction has been canceled, the primary system transmits to the secondary system or systems said message, and the secondary systems restore all affected data back to the state prior to the updates on the basis of the pre-updated information.