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OS/390
open-in-new
<p>OS/390 is an <a href="/facts/IBM/QszA7nwd">IBM</a> <a href="/facts/Operating_system/8XTuvMh2">operating system</a> for the <a href="/facts/System%2f390/lzkp2UE5">System/390</a> <a href="/facts/IBM_mainframes/0kPkgADx">IBM mainframe computers</a>. </p>