There is a port of the linux kernel to allow it to be run in userland. http://user-mode-linux.sourceforge.net/
It can be restricted from access to the hardware, but it can also be set up to do networking, mount filesystems etc. It does provide some advantages in that you can use a debugger or profiler from the host system which means that you can set breakpoints in the kernel and treat it as if it were any other userland program. I guess the next step is for someone to compile it on Cygwin and then claim that they are running Linux on Windows. I found it from a story on O'reilly devcenter http://linux.oreilly.com/pub/a/linux/2001/11/29/UserModeLinux.html ]\[33t0 http://www.efn.org/~laprice ( Community, Cooperation, Consensus http://www.opn.org ( Openness to serendipity, make mistakes http://www.efn.org/~laprice/poems ( but learn from them.(carpe fructus ludi) http://allie.office.efn.org/phpwiki/index.php?OregonPublicNetworking
