So what defines a derived work? If you implement from scratch, but in order to implement must look at the existing implementation in order to get it correct, th

So what defines a derived work? If you implement from scratch, but in order to implement must look at the existing implementation in order to get it correct, then it's possible (probable?) that the new implementation is directly derived from the original implementation. It's not like Linux has a published license free spec. Unless they reverse engineered the system calls (possible but omg I think that would have been hard), then I'd be willing to bet that this could be easily considered derived work from the GPL.