MS-DOS didn’t steal from CP/M, according to new report, but you can win $200,000 if you prove it did

It has been rumored for a long time that MS-DOS, Microsoft’s discontinued operating system for x86-based computers has been copied on CP/M, another popular OS developed by Digital Research in the 1970s for Intel 8080/85-based computers.

According to a new report from the IEEE Spectrum blog (via The Next Web), Bob Zeidman, an American engineer and consultant will offer a $200,000 reward to anyone that can prove that Microsoft has copied the code from CP/M to develop MS/DOS in the early 1980s.

Over the last four years, Zeidman himself has studied the MS-DOS source code on two occasions but he did not find any evidence proving that Microsoft copied the source code from CP/M. However, he did find during its latest research that he presented at the Vintage Computer Festival West earlier this month that at least 22 system calls (the mechanism used by an application program to request service) on MS-DOS had the same function and function number as the code on the CP/M operating system. That is ;-)

While he does not have enough evidence to prove that MS-DOS was copied, Zeidman hopes that the $200,000 reward will push other people to look into it. If you’re interested, you have a look at Zeidman’s two CP/M, MS-DOS comparisons of code and reference materials over here.

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Do you believe MS-DOS is or isn't a copy of CP/M?