在科學的研究上，會有許多科學儀器會產生出大量的資料，全世界的科學家可以透過格網的服務來取得、共享這些資料，他們透過資料格網的服務將這些在遠處的資料產生一份複本在本地端，通常都只用一個大檔案的一小部分，然而，整個檔案的複製需要讓這些科學家等待一段長時間的複製時間，並且在本地端要準備一塊非常大的磁碟空間來儲存這個檔案，再者當檔案有多份的複本的時候，如何在眾多複本中維護資料的一致性也是一種挑戰。在這篇論文中提出了「水龍頭」的區塊式共享機制，它可以減少在複製檔案時資料傳輸的時間並且避免浪費本地端磁碟的空間，它只會搬移使用者所需要的資料區塊而不是把整個檔案從遠端整個搬移到本地端，此外對於使用者而言，它利用了分散式共享記憶體的子系統來提供使用者所需要的資料和達到資料一致性。在實驗的結果中可以看到區塊式共享機制可以有效的節省傳輸資料的時間。

A large amount of data is produced by scientific instrument and shared with world-wide scientific communities in the grid environment. Scientists could replicate a shared file through data grid service. They usually use only a small part of a large file.
However, the file level replication burdens scientists on waiting for long transfer time and
preparing a large size space on local disk. Furthermore, keeping the synchronization of
the numerous of the replica is a challenge. In this thesis, a DSM-based block level sharing mechanism for Grid named SPIGOT is proposed. It can reduce the data transfer time and avoid wasting users’ local disk space. It makes users just get the necessary part of data instead of the whole file. Besides, it is transparent to users because the DSM
subsystem of SPIGOT provides the necessary part of data and maintains the synchronization of the replicas. Experimental results show that SPIGOT successfully reduces the turnaround time of the data-intensive application which uses a small part of a large shared file.

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