Microsoft famously bought the rights to a PC operating system, 86-DOS, and then turned around and sold the rights to use the software, now called MS-DOS, to IBM in 1980, while retaining the right to license it to other PCs. The result was that Microsoft was able to grow its operating system business to the massive company that it is today.
A few people believe that the code in the original 86-DOS software contained code copied from another older PC OS, CP/M. However, the creator of that OS, Gary Kildall, never took any legal actions against either Microsoft or IBM and died in 1994.
Now a new report from a forensic computing researcher named Bob Zeidman, were published recently in IEEE Spectrum, claims to have used its own tools to find any copyright issues in software. In short, Zeidman claims that, according to his tools, 86-DOS has no code copied from CP/M.
But is that the whole story? Wired claims that Zeidman was also called in as an expert witness for Microsoft in its current patent fight against Motorola. He admits this connection but said that his involvement in the case ended in August 2011 and his research into the 86-DOS code controversy started in December just for fun.
In any case, everyone loves a good conspiracy theory and despite these new findings, we are sure that some people will continue to believe that the original 86-DOS code is copied in part from CP/M.