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3.1 Overview
We organize our discussion according to the four steps shown in
Figure 1:
- 1.
- Logging of user operations. When a file is updated on a
client, the client keeps the new file value V (the contents of the
file) and also logs the user operation O.
- 2.
- Shipping of operation log. If the network bandwidth is
low, the client does not ship V to the server. Instead, it ships
O, the fingerprint of V, and other meta-data to a surrogate
client.
- 3.
- Re-execution of operations. The surrogate re-executes Oand produces a file value V'.
- 4.
- Validation of re-execution. The surrogate validates the
re-execution by checking the fingerprints and meta-data. If it
accepts the re-execution, then it will present V' to the server;
otherwise, it will report failure to the client, which will then fall
back to value shipping and ship V directly to the server.
Copyright 1999 by Y.W. Lee, K.S. Leung, and M. Satyanarayanan