The system must determine on which machine the rule should be run.
Remembering the machine that created the file is useful but not
sufficient. First, the original machine may be down or heavily load
at reconstruction time. Second, the original machine's environment may
have changed since the file was created. Before a reconstruction rule
is saved, MBFS collects the architecture and operating
system of the machine and stores them with the reconstruction rule.
At reconstruction time, the system searches for machines satisfying
both architecture and OS, and chooses one of them on which to run the
reconstruction rule. If no machine is found, an error message is sent
to the owner of the file saying the file could not be reconstructed.