CP/M was developed on TOPS-10 and copied a lot of concepts from it. I can't immediately tell whether or not this is an example, but for any given eccentricity of CP/M it's a good bet that it came from TOPS-10.

It's amusing that almost the same can be said about NT: for any given eccentricity of Windows NT it's a good bet that it came from VMS, since the two had the same principal designer.