There was a nice analysis of this done by Bob Zeidman where he compared the released CP/M 2.0 and DOS 2.0 source code. His basic conclusion was that source and

There was a nice analysis of this done by Bob Zeidman where he compared the released CP/M 2.0 and DOS 2.0 source code. His basic conclusion was that source and basic commands were not copied, but that a large number of the system calls were copied. https://www.scirp.org/journal/PaperInformation.aspx?PaperID=71259 https://www.scirp.org/journal/PaperInformation.aspx?PaperID=...