Summary: | 碩士 === 國立交通大學 === 資訊科學學系 === 84 === With the development of distributed systems and object-
oriented technology, object-based distributed processing has
been highly valued. Therefore, OMG (Object Management Group)
is devoting itself to the standardization of distri-buted object
exchange, and CORBA (Common Object Request Broker Architecture)
is exactly its first standard for distributed object exchange.
There are more and more COSS (Common Object Service
Specification) on CORBA,but no common specification about fault-
tolerance exists now. Since classes of large-scale distributed
applications will have to deal with unpredictable communication
delays, with partial failures, and with networks partitioning,
there have been many reseraches for fault-tolerance on CORBA
environment such as ELECTRA, Orbix+ISIS, etc.
We propose a "warm stand-by" replication approach in this
thesis. When an object (the primary object) is invoked, it
will invoke a secondary object, andthe primary object will log
the messages and checkpoint the state to the se- condary object
periodically. If the primary object fails, the secondary can
take over automatically. We provide a library according to the
style of COSS.With such an interface, programmers can write
programs with fault-tolerance a-bility. The whole model has
been implemented on Orbix, which is a full imple-mentation of
CORBA specification.
|