One of the best in the field. :) Although I think they just have dev assurance. Not total high assurance. An early one with total was GEMSOS by Schell, one of INFOSEC&#x27;s founders:<p><a href="http:&#x2F;&#x2F;www.iwia.org&#x2F;2005&#x2F;Schell2005.PDF" rel="nofollow">http:&#x2F;&#x2F;www.iwia.org&#x2F;2005&#x2F;Schell2005.PDF</a><p>Smartcard OS by Karger, another founder of INFOSEC:<p><a href="https:&#x2F;&#x2F;www.acsac.org&#x2F;2012&#x2F;workshops&#x2F;law&#x2F;pdf&#x2F;Lessons.pdf" rel="nofollow">https:&#x2F;&#x2F;www.acsac.org&#x2F;2012&#x2F;workshops&#x2F;law&#x2F;pdf&#x2F;Lessons.pdf</a><p>A comparable one for dev assurance, but maybe easier to emulate, was CompCert. Testing of it against many other compilers validated formal verification gave best reliability.<p><a href="http:&#x2F;&#x2F;gallium.inria.fr&#x2F;~xleroy&#x2F;talks&#x2F;compcert-lctes08.pdf" rel="nofollow">http:&#x2F;&#x2F;gallium.inria.fr&#x2F;~xleroy&#x2F;talks&#x2F;compcert-lctes08.pdf</a><p>Ironically, Microsoft compete neck-to-neck with seL4 in terms of verification with their excellent work on VerveOS:<p><a href="https:&#x2F;&#x2F;people.csail.mit.edu&#x2F;jeanyang&#x2F;papers&#x2F;pldi117-yang.pdf" rel="nofollow">https:&#x2F;&#x2F;people.csail.mit.edu&#x2F;jeanyang&#x2F;papers&#x2F;pldi117-yang.pd...</a>