| In multiple replicated file systems, every copy of a file must be identical. It is important to check this constantly and resolve differences, and a number of techniques have been proposed for it. In this thesis, we present a new technique for locating corrupted page copies, outdated page copies, and missing page copies in multiple replicated file copies.; In the first part of this thesis, we present four communication models and four communication protocols that efficiently detect and locate the corrupted page copies, the outdated page copies, and the missing page copies in multiple replicated file copies. Whereas other previous works consider locating only corrupted page copies, our protocols can locate outdated page copies and missing page copies as well as corrupted page copies. In addition, whereas other previous works are based on majority rule to determine the correct copy, our protocols are not. The performances of these protocols is measured in terms of the number of transmissions and the number of transmitted signatures. We compare these performances with one another and also compare them to the performances of other previous works.; In the second part of this thesis, we present a new application in reliable satellite broadcasting. In traditional satellite broadcasting, the source site retransmits a packet until every destination site receives it correctly. This requires a number of retransmissions through the expensive satellite link. However, if we can ensure that at least one destination site receives the packet correctly in the first transmission and if we assume that every destination site is interconnected through a wired network, we need local intercommunications, instead of retransmissions, to recover errors. The technique for locating corrupted page copies at multiple site can efficiently be used for these local intercommunications.; In the third part of this thesis, we consider a ring network as a special network configuration. We present a protocol using a coordinator site and a master signature and apply it to reliable satellite broadcasting. |
