In regard to "1970s code lineage" I think the parent is referring to the fact that the original XNU codebase incorporated parts of the BSD kernel, which was rel

In regard to "1970s code lineage" I think the parent is referring to the fact that the original XNU codebase incorporated parts of the BSD kernel, which was released in the 70s. The same can be said of the code lineage of FreeBSD and I guess some other UNIXs I think. Windows NT on the other hand, while having similarities to VMS I don't believe at any point shared actual code.