<i>the ideological underpinnings are what allowed Linux to overtake BSD during &quot;the troubles&quot; of the early 90s</i><p>As I understood it, also to a degree witnessing it as it happened, this lawsuit spiked BSD at the critical period: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;UNIX_System_Laboratories,_Inc._v._Berkeley_Software_Design,_Inc" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;UNIX_System_Laboratories,_Inc....</a>.<p>It certainly took Linux a long time to get in the ballpark of quality that BSD started out with at the gate, including the standard TCP&#x2F;IP stack most everyone used, including Microsoft (initially, at least).