LogicalFile Management

It is often the case that when working with large physical files in a geographically distributed computing environment that one has various physical files which are byte-for-byte identical, but yet are distributed geographically. When this relatively common situation occurs, deciding which of these geographically dispersed large physical files to use for a particular operation becomes a problem. For example, if one decides to copy one of these physical files to a computing resource on which it does not currently exist, then choosing the ``wrong'' copy can cause a wait of hours as this large physical file is copied through a connection which is already at its saturation point. GAT deals with this very situation by introducing the LogicalFile construct.

A LogicalFile represents a set of physical files which are byte-for-byte identical but geographically dispersed. This construct is useful for the very case described above, as well as other related cases. A LogicalFile representing the various physical files in the previous example can be used to facilitate the above copying. However, the actually decision as to which of the various physical files to use to make the copy is left up to GAT and its minions they decide which of the physical files is closest in ``network space'' to the target location, then use that physical file to make the new copy so that the process is done as efficiently as is possible.

• Creating and Destroying LogicalFiles
• Adding and Removing Files
• Replicating LogicalFiles
• Examining LogicalFiles