Is creating a new operation system that is capable of running windows/mac/linux programs legal?
<p>If one could create a new operation system that could run/support
all the programs that run on Windows/Linux/Mac or whatever operation system one could find, could Microsoft, the creator of windows, for example, sue the creator of this new operation system?</p>

<p>It is legal <em>if</em> the new operating system you create do not contain any copied source code, and you do not infringe any patents.  </p>

<p>However, if your clone becomes extremely successful, that does not protect you from an expensive lawsuit, as is demostrated by <a href="http://www.embedded-computing.com/embedded-computing-design/software-forensics-lay-ms-dos-cp-m-controversy-to-rest" rel="nofollow noreferrer">Caldera vs. Microsoft</a>.</p>

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