Green Hills Software

Founded in 1982 by Dan O'Dowd and Carl Rosenberg in Santa Barbara. The product line centres on INTEGRITY, a real-time operating system built for systems where a fault can cost lives — aircraft (DO-178), defence, medical devices and cars.

The INTEGRITY-178B separation kernel was the first in the world to reach Common Criteria level EAL6+ — formally proven isolation between processes. The company also makes compilers and the MULTI development environment. Founder O'Dowd is these days best known outside the industry for his campaigns against Tesla's self-driving.