Not a map per se, but I find bxr.su is a great resource to browse *BSD source code. OpenBSD is quite close to its&#x27; 4.4BSD roots, so &quot;The Design and Implementation of the 4.4 BSD Operating System&quot; book should still be pretty accurate.<p>There is also a presentation on openbsd.org&#x2F;papers that seems relevant &quot;OpenBSD Kernel Internals: The Hitchhiker&#x27;s Guide&quot;. Direct link to PDF : <a href="http:&#x2F;&#x2F;atmnis.com&#x2F;~proger&#x2F;openkyiv&#x2F;openkyiv2009_proger_sys.pdf" rel="nofollow">http:&#x2F;&#x2F;atmnis.com&#x2F;~proger&#x2F;openkyiv&#x2F;openkyiv2009_proger_sys.p...</a>