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Cygwin: Salvation on Windows
Cygwin provides a rather unique, and sometimes inconvenient, mechanism for installation. A small network-install executable is provided, which consults online repositories for downloads of installation artifacts. The install executable also relies on locally-written meta-data to keep track of the entire installation footprint.
Cygwin makes a particularly powerful solution for a client-side agent in providing central command-n-control with a centralized backup/archival system. Here are some details around how Albert Lea Data has devised such a solution.
This is the recipe for how the client-side agent footprint is bundled, and how to go about upgrading it.