Shibboleth SP windows (msi) installer

[Rod Widdowson]

> That mostly makes sense to me, but how does the system treat a file that's named the same in both
> packages but is newer in the upgrade? Does that constitute an increase to the reference count? I
> assume so...

The installer appears to do magical things with modified dates or explicit versions
(http://msdn.microsoft.com/en-us/library/aa368267.aspx() so if the same component has the same file name then the newest "wins".  I
think that I need to research this further since I'd quite like to be explicit rather than trust modified dates...

> I don't quite know how merge modules for libraries play into this either.
> Do they just implement the same kind of upgrade logic for the files that the main installer would?

Good point, I'll need to investigate this further.  I *suspect* that they follow the same install/uninstall rules as the master MSI.
I'll check, research, and then check again 

/Rod