在CORBA環境上之可容錯物件設計與實作

Abstract

隨著分散式系統與物件導向技術的發展，以物件為基礎的分散式處理已廣 受重視。因此，OMG (Object Management Group) 致力於分散式物件交換 標準的制定，CORBA(Common Object Request Broker Architecture) 正 是它制定的第一個分散式物件交換的標準。但是，這套標準並未包含容錯 處理，若有一物件發生錯誤就會影響到整個程式的進行。本篇碩士論文詳 述在CORBA的環境下，如何配合物件導向程式語言 C++ 的特性 (封裝、繼 承、動態繫結)，引進 checkpoints 和 audit trails 的技術，提供程式 設計師更高階的發展環境 - Phoinix，讓設計者可以用宣告一般 C++ 物 件的方式來宣告具有容錯能力的物件，不必操心繁複的容錯處理細節，卻 又能兼顧程式執行效率。 Phoinix 現已被實作在一個符合 CORBA 規格的 實際產品 Orbix平台上，藉由我們所提供的函式庫與改良版的 IDL Compiler，設計者可以簡便地設計出具有容錯能力的分散式應用程式。 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 distributed object exchange, and CORBA (Common Object Request Broker Architecture) is exactly its first standard for distributed object exchange. But the CORBA specification does not cover fault-tolerance. Consequently,if an object within some application occurs fault, the progress of the whole application will be obstructed. This thesis describes how to make use of the properties of the object oriented language C++ (Encapsulation、Inheritance、 Dynamic binding)to embed checkpoints and audit trails technology into CORBA, providing programmer with higher level development environment - Phoinix, in which programmer can declare fault-tolerant object just like a conventional C++ object without worrying about how the fault-tolerance is implemented,and keep the application executing efficiently. Phoinix has been implemented on the platform Orbix, which is a full implementation of CORBA specification. Programmer can design fault-tolerant distributed application simply by means of the library and enhanced IDL compiler we provide.