Abstract: A fault-tolerant messaging system comprises a primary broker, a first network, a back up broker, and a second network. The primary broker and the back up broker are coupled to the first network for communication with clients thus creating a messaging system. The primary broker and the back up broker are also coupled to the second network for replicating state from the primary broker and the back up broker, and also sending transaction events immediately to maintain synchronization. The brokers further comprise a replication module for communicating state between the primary broker and the back up broker, a recovery module for performing recovery on the back up broker upon failure of the primary broker, and a fault-tolerant connection module for establishing a fault-tolerant connection between the primary broker and the back up broker over the second network. The present invention also includes a number of novel methods for performing fault tolerance.

Abstract: A data processing system provides annotation of a document through an electronic tablet, a keyboard and an audio assembly. An annotatable document is generated from a window of a multiwindow support program running independently of the annotation program in the data processing system. For each window of the multiwindow program, a working document is generated and is annotatable by the annotation program and apparatus. An annotatable document is also generated from the whole screen view of overlapping windows produced during execution of the multiwindow support program. Annotated working documents may be subsequently stored in and thereafter retrieved from the database of the multiwindow support program.