After the examination of the code was done by Zeidman, the previously unavailable source code for MS-DOS was donated by Microsoft to the Computer History Museum. Zeidman has used QDOS to do his original analysis. Later, the museum also traced and released a more complete version of the CP/M source code. Zeidman re-ran his analysis, and presented the results at the Vintage Computer Festival West on August 6. So, what was the conclusion of the analysis? According to the investigation, there was no evidence of copying code nor the proof to back-up a long-running rumour that there is a secret command in MS-DOS that can be called to print out a copyright notice in Gary Kildall’s name. For those unfamiliar, Gary Kildall was an American computer scientist and microcomputer entrepreneur who created the CP/M operating system. While it was confirmed that there were signs of copying code, however, Zeidman did find out that no less than 22 system calls were copied from CP/M to MS-DOS, which had the same function and function number. The system calls are the commands used to request an action, like reading from a hard disk or sending text to a printer. According to Zeidman, Kildall “might have had a copyright claim for the system calls that it could have litigated against Microsoft. On the other hand, there is a good chance Microsoft could have beaten such litigation by claiming it was a ‘fair use’.” Zeidman has had a lot of pushback in the meantime since his original article was published, partly because it seems that at the time, he had an open consulting contract with Microsoft. However, Zeidman claims that it was an old and inactive contract with Microsoft and he has since cut off all ties. Therefore, he has declared a prize money of $200,000, of which $100,000 is for anyone who can use “accepted forensic techniques” to prove the copying, and another $100,000 for anyone who can determine the secret Kildall copyright function. His full analysis of the code and supporting documents are here. Source: IEEE Spectrum
