Method, computer readable medium, and system for monitoring the state of a collection of resources

Abstract

A system and method for synchronizing changes among multiple copies of data is disclosed. The system and method allows the data to be synchronized without any copying or transferring of those portions of the data that have not been changed. In particular, the system and method preferably uses an identifier to represent the current state of the data and the identifier is used to determine what, if any, changes have occurred to the data. Thus, instead of comparing the data itself to see if changes have been made, the identifier is used to simply and easily determine if changes were made to the data. Each identifier preferably includes a first portion that identifies a particular source for the data and a second portion that includes a change number that is changed each time the underlying resource is modified. The identifier is preferably opaque or transparent to the client such that the client does not have to understand anything about the format or use of the identifier. Advantageously, an opaque identifier allows the system and method to be compatible with a wide range of data and programs.