隨著無線通訊技術的長足進步，分散式計算應用程式的執行已不再侷限於固定網路的環境。愈來愈多具備有無線通訊介面的筆記型電腦或個人數位助理已擁有強大的計算能力，足以作為參與分散式計算的一員。此一行動計算的概念將無可避免地受到廣大的重視與採用，以利資源的取得與交換。為了使得分散式計算系統具有高可靠度，查核點與錯誤回復技術發展迄今以逾二十年。然而，行動計算環境具有某些特殊性質，如可移動性、離線模式、有限的無線通訊頻寬、脆弱的儲存設備、以及行動主機之有限電源供應等等。這些具有挑戰性的課題並未出現在傳統分散式計算環境，因此，舊有適用於傳統分散式系統的查核點及錯誤回復技術並不適用於行動計算環境，本文主要將介紹文獻當中所提出的適合於行動計算系統之查核點與錯誤回復技術，並且將討論回復技術在設計上的一些考慮因素，以期克服這些行動計算系統特有的性質。
As wireless communication technology advances, the execution of distributed computing applications is no longer constrained in a static network environment. More and more powerful laptop computers and PDAs, which are equipped with wireless communication interfaces, become possible participants of a distributed computing application. It is inevitable that the paradigm of mobile computing will soon be widely adopted to facilitate information access and exchange. To achieve high reliability, checkpointing and rollback-recovery techniques for distributed computing systems have been developed and discussed for over two decades. However, there exists some unique characteristics in mobile computing environment such as user mobility, disconnection mode, limited wireless bandwidth, vulnerable storage, and power limitation of mobile devices. These issues bring new challenges that are not present in traditional distributed computing systems. As a result, those existing checkpointing techniques for distributed computing systems are not well suited for a mobile computing environment. In this paper, we will introduce several new or existing checkpointing and recovery techniques for mobile computing systems. We will also discuss a number of design considerations for a rollback-recovery protocol that can cope with the unique features of a mobile computing system.
Relation:
Journal of Internet Technology= 網際網路技術學刊 1(1), pp.11-20
