Holy cow, I wrote a book!
We saw last time that
the unattend file lets you change some Windows configuration settings
that cannot be changed after Setup is complete.
But one of the things you can't change is the location of the
Program Files directory.
Many people wish they could relocate their
Program Files directory to another drive in order to relieve disk space
pressure on the system partition.
Why won't Windows let them do this?
Now that NTFS is mandatory for the system volume
(it took only 13 years to get there!),
Windows itself can start taking advantage of NTFS features.
Windows Setup takes advantage of hard links.
A large percentage of the files installed by Windows
are hard-linked to copies in the
C:\Windows\WinSxS directory for reasons I do not understand,
but the phrase "component store" may be part of it.
(This is why asking Explorer for the size of the C:\Windows
directory gives a misleading view of the actual amount of disk
space occupied by Windows,
because Explorer uses
a naive algorithm which counts each hard link as a separate file.)
Oh, and in Windows 7, the two copies of Notepad
are now hard links to each other.
Ah, but one of the limitations of hard links is that they
cannot span volumes.
Some of the hard links out of the WinSxS directory point into
and this in turn requires that the Program Files directory
be on the same volume as your Windows directory.
Sorry for the inconvenience.