zlacker

So I have this mod manager for Elder Scrolls: Oblivion that sets up a virtual filesystem as an overlay over the game's original directory structure, and then launches the game in a way that makes the game see the overlay as if they were the original files. I am very impressed at what seems like outright computer voodoo, I had no idea Windows had those kinds of APIs or that kind of capability.

I don't know how this tech works but I feel like we could have had this already using the tech I described above.

>>pdntsp+(OP)
Filesystem (and registry) redirection has been around in Windows for a while, and is used to e.g. make sure that pre-Vista apps still run if they do things like trying to write to "Program Files". But that all assumes that the app is not adversarial - proper sandboxing is a different story.

>>pdntsp+(OP)
I'm pretty sure such thing is implemented by hooking OS functions that are dealing with directory enumeration, create/open file, etc - and then redirecting to custom code that provides virtual files & their contents. There's no standard Windows API for that, aside writing custom driver. But hooking such functions is relatively straight forward process because they are imported from well known shared libraries - you just need to make sure you hook all the functions that are relevant to filesystem operations.