F. Guerra, J. Miranda, A. Alvarez, and S. Arevalo. An Ada Library to Program Fault-Tolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Int. Conf. on Reliable Software Technologies, volume LNCS 1251, pages 230--243, London, United Kingdom, June 1997. Springer.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....the same answers. The results of the replicas are filtered, so that the results of a single replica are returned to the client (transparent replication) A replicated group can act as a client of another group. Replication transparency is provided by the underlying communication system, Group IO [GMAA97] that filters the replicated requests so that a single message is issued (Fig. 1.c) This type of communication allows building programs with active replication and minimal additional effort from the programmer. That is, the programmer programs the group as if the group were made out of a single ....

F. Guerra, J. Miranda, A. Alvarez, and S. Arevalo. An Ada Library to Program FaultTolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Int. Conf. on Reliable Software Technologies, volume LNCS 1251, pages 230--243, London, United Kingdom, June 1997. Springer.

....be filtered to avoid performing the call multiple times. This filtering guarantees that the call is executed exactly once. The reply is sent back to all the replicas. This filtering can be automatically done using a communication library providing m to n group communication [13] like GroupIO [8], or implementing this facility on top of a group communication library [14] 3. Enforcing determinism In order to guarantee replica consistency determinism must be enforced. The sources of non determinism can be classified as external and internal. The external environment of the replicas is ....

....Drago [17] Both TransLib and Transactional Drago support transactional group servers. The implementation of TransLib has been made in Ada 95 [1] using objects and tasks. Server threads are implemented as Ada tasks and thus, services are task entry points. Client server communication uses GroupIO [8], a group communication library providing reliable total ordered multicast. An interesting feature of this library is that it provides n to m communication, that is, when a replicated group performs a call, the library takes care of not delivering duplicate messages. TransLib is adaptable in the ....

F. Guerra, J. Miranda, A. Alvarez, and S. Arevalo. An Ada Library to Program Fault-Tolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Int. Conf. on Reliable Software Technologies, volume LNCS 1251, pages 230--243, London, United Kingdom, June 1997. Springer.

....has the caller) Therefore, the effect is as if only one request is made. The reply is sent back to all the replicas. This can be automatically done 5 Figure 2: Interaction with a replicated server using a communication library that provides mtongroup communication [LCN90] like GroupIO [GMAA97] or implementing this facility on top of a group communication library, approach taken by the Eternal system [NMMS99] Since request submission is blocking and request acceptance explicit, it is not possible for a server to make reentrant invocations. In the 2PC protocol, the replicated server ....

....programming language [PJA98] Both TransLib and Transactional Drago support replicated group servers. TransLib is written in Ada 95 [Ada95] using objects and tasks. Server threads are implemented as Ada tasks and thus, services are task entry points. Client server communication uses GroupIO [GMAA97] a group communication library providing reliable total ordered multicast. An interesting feature of this library is that it provides n to m communication, that is, when a replicated group performs a call, the library takes care of not delivering duplicate messages. TransLib is adaptable in the ....

F. Guerra, J. Miranda, A. Alvarez, and S. Arevalo. An Ada Library to Program Fault-Tolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Int. Conf. on Reliable Software Technologies, volume LNCS 1251, pages 230243, London, United Kingdom, June 1997. Springer.

....distributed language, Drago [30] with transactional mechanisms in a new version of the language called Transactional Drago [31] TransLib has also been used to provide run time support for Transactional Drago. TransLib uses as communication layer, the group communication library GroupIO [32]. This library provides reliable multicast. Group Transactions provide replicated and cooperative transactional groups. Transactional replicated groups improve the availability of transactional servers, by replicating them and their associated data. Transactional cooperative groups reduce the ....

F. Guerra, J. Miranda, ' A. ' Alvarez, and S. Ar'evalo. An Ada Library to Program Fault-Tolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Int. Conf. on Reliable Software Technologies, volume LNCS 1251, pages 230--243, London, United Kingdom, June 1997. Springer.

....A new thread in each agent will be created to accept all the calls from each client transaction in order to prevent transactions from seeing uncommitted results of other transactions. Figure 5: Call Path Transactional Drago is preprocessed to Ada 95 and service calls from two libraries: GroupIO [6] and TransLib. The former provides support for group communication and the latter for transaction processing. To use the Multithreaded Rendezvous design pattern it is necessary to provide a concrete Comm class, concrete CallObject classes for the different concrete ServerObject classes, concrete ....

F. Guerra, J. Miranda, ' A. ' Alvarez, and S. Ar'evalo. An Ada Library to Program Fault-Tolerant Distributed Applications. In K. Hardy and J. Briggs, editors, Proc. of Reliable Software Technologies, Ada-Europe'97, volume LNCS 1251, pages 230--243. Springer, 1997.

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