The OpenBSD project produces a free, multi-platform 4.4BSD-based UNIX-like operating system. Its goals emphasize portability, standardization, correctness, proactive security, and integrated cryptography. OpenBSD supports binary emulation of most programs from SVR4 (Solaris), FreeBSD, Linux, BSD/OS, SunOS, and HP-UX.
MutekH is a portable and free operating system for embedded platforms originally developed at the SoC department of the LIP6 Laboratory in Paris. MutekH is a set of libraries built on top of an exo-kernel designed to support heterogeneous multiprocessor platforms. MutekH is fully configurable to match every application's needs. It is used in several research projects and currently supports x86, arm, mips, and powerpc processors.