The thing was Micro-Soft at the time was selling BASIC, COBOL, and FORTRAN languages without paying a license fee to use them from the college or company that held the copyright license. You could say that Microsoft made a clone of the languages for microcomputers, but did not invent the languages themselves. This cut down on research and design costs to use an existing language and write a clone of it instead of paying a license fee for the language software and port that.<p>So at the time the people who pirated Micro-soft tapes and floppies claimed that it was an illegal port in the first place. I don&#x27;t know if they are correct or not but copyright was not enforced in the 1970s and 1980s because they had different IP laws then than we do now.<p>When Microsoft bought 86-DOS&#x2F;Q-DOS it had violated CP&#x2F;M-86 patents by using the API and in fact there was a CP&#x2F;M to DOS converter for programs because of how similar both operating systems were. <a href="http:&#x2F;&#x2F;www.wired.com&#x2F;2012&#x2F;08&#x2F;ms-dos-examined-for-thef&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.wired.com&#x2F;2012&#x2F;08&#x2F;ms-dos-examined-for-thef&#x2F;</a> But as it turns out you can&#x27;t copyright an API and Linux uses the Unix API.<p>So saying Microsoft stole IP is very hard to say, they did develop alternatives to the originals that their software did the same things as. None of what they made early on they sold was original and was based on something else.<p>The only reason why IBM chose DOS instead of CP&#x2F;M is that DOS cost less per license than CP&#x2F;M. Plus IBM got access to Microsoft BASIC for their PC ROM.<p>Micro-Soft saw a need for a programming language for many microcomputers that didn&#x27;t even have software yet, it allowed others to use the languages to write software for the many different microcomputers. So in a way Microsoft making their own version of those languages without paying a license fee opened up a lot of doors for the 8 bit and 16 bit market. Because no other company was doing that at that time.<p>To this day many free and open source projects make clones of the original products by using the same API as the original and writing their own code from scratch. If API becomes copyrighted it would shut those projects down.<p>The IBM PC Clone market only happened because they cloned the PC BIOS by reverse engineering it and writing their own BIOS that uses the same API calls as IBM&#x27;s BIOS. Then Microsoft licensed MS-DOS to the PC clone companies who made PCs cheaper than IBM and lead to a reduction in cost of microcomputers.<p>So in honesty Microsoft sort of started the API cloning business and it allowed the PC Cloners to take over IBM&#x27;s marketshare and drive IBM out of the PC business.