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Path should be a system call
ATH should be a system call (... but...
Instead of trying various file names, it will just go and lists directories right away; it is probably this & some caching mechanisms that allow it to find some modules pretty quickly. This would already cut down on the number of system calls, and, if this is going over a network, the required roundtrips. While I'm not sure what implementation they're using underneath, they have at least a good chance for not having to try every combo all the time, given their database "filesystem".
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