File system protection between websites

[ckup1]

If someone can definitively answer this it will save me writing a whole lot of scripts to test it. (For Plesk 6.5 Windows)

Is each individual web-site file systems protected from one anothers CGI and ASP scripts ? (i.e., the CGI and ASP scripts for each website run as different users with operating system level restriction to just that websites file space) (i.i.e., a normal way of testing this is to write a CGI or ASP that simply recurses the entire C: drive and it should only have read access to the website space)

I think you get what I mean... can anyone answer this?

-Chris.