在分散式系統上之可容錯物件應用環境

Abstract

隨著分散式系統的發展，提供一個很簡便的方式去發展可信賴的分散式軟 體已成為一項重要的工作。由於物件的概念很適用於分散式環境，物件導 向技術就成了建構分散式系統的重要工具。本篇碩士論文主要在詳述一個 於分散式系統中提供容錯能力的物件導向式應用程式環境－FTOAE 。它提 供使用者設計具有不同共享能力及容錯能力的物件。系統也提供一個前置 編譯器，可將由改良版C++寫成的原始程式編譯成可被傳統C++編譯器處理 的程式。藉由一個以代理人為主的物件管理伺服器，分散式物件的使用將 是完全透明的。FTOAE已被實作在一個使用現有RPC機制為基礎的區域網路 上，但是原來伺服器的執行行為則作了修改，以配合系統的需要。 With the development of distributed systems, it is an important issue to provide an easy way for writing reliable distributed softwares. Because the object concept is well suited to distributed environments, object-oriented techniques have become the predominant means for modeling distributed systems. This thesis describes the design and implementation of an object oriented application environment, called FTOAE, that provides fault tolerance in distributed systems. Users can design different types of objects with different degree of fault tolerance. A pre- compiler has been developed for compiling the source program, which is coded by an enhanced version of C++ language in the FTOAE, into target programs, which can be compiled by a conventional C++ compiler. The usage of distributed objects is made entirely transparent by means of an agent based class manager. It has been implemented on a local area network according to the existing RPC mechanism, but the behavior of the Sun's RPC server has been fixed to fit the requirements of the FTOAE.