NT borrowed a lot form VMS, I'm sure. But Apple took NeXTStep, a Mach kernel, did a facelift on the UI, and put Carbon and a Mac OS compat layer on top. On XP,

NT borrowed a lot form VMS, I'm sure. But Apple took NeXTStep, a Mach kernel, did a facelift on the UI, and put Carbon and a Mac OS compat layer on top. On XP, well, MS's reaction was not as calm. They had to release Vista with tons of FX as OSX looked much better than XP. Everyone copied OSX' interface, even under GNU/Linux/BSD and Fluxbox envs.