Coyotos and Genode are two operating systems about which I had never heard that were mentioned in an Ikarus Users mailing list thread that doesn’t seem to have been mirrored online.
Coyotos is a secure, microkernel-based operating system that builds on the ideas and experiences of the EROS project.
We understand the complexity of code and policy as the most fundamental security problem shared by modern general-purpose operating systems. Because of high functional demands and dynamic workloads, however, this complexity cannot be avoided. But it can be organized. Genode is a novel OS architecture that is able to master complexity by applying a strict organizational structure to all software components including device drivers, system services, and applications. The Genode OS framework is the effort to advance the Genode OS architecture as a community-driven open-source project.