在Windows NT 上的分散式異動檔案服務設計與實作

Abstract

分散式異動檔案服務可視為分散式檔案服務的擴充,它允許客戶程式集合 一組操作使它們不可分割的執行。在我們的系統上,我們在每一站上設計 了一個transaction manager及一個 lock manager, transaction manager負責客戶的不可分割性及可復原性;而 lock manager負責平行控 制。在分散式系統上,一個異動可能牽涉到多個不同的伺服器,因此需要一 個協調者去整合所有異動伺服器的動作,我們系統使用Two-Phas Commit Protocol去整合所有異動服務的決定。我們以Windows NT 的thread來設 計伺服器,以允許多客戶可同時接受服務。使用thread可讓程式間的溝通 容易達成且同布問題也較容易處理,這使得系統的執行效率提生。 A distributed trnsactional file service can be regarded as annsion of distributed file service. It suports a skeletona client program to group the operations together toatomic. In our system, we design a transaction manager and a lock manag- er in each site. The transaction manager is responsible for ato- micity and recovery of client operations, while the lock manager is responsible for concurrency control. In disrtibuted systems, one trans action one transaction may invoke more than one trans- saction manager that resides at different sites. Thus, it needs to coordinate the network-wide commitment of all servers participating in a transact on. The Two-Phase Commit Pr- otocol is used to commit the distributed transactions in our sy-tem. We use the Windows NT treads in a server offering concurrent ac- cess to clients. Use of threads makes IPC(Inter- Process Communi-ation) and synchronization easily and improves the system perf- ormance.