LynxOS-178: A Low-Risk Path to DO-178B Certification

LynxWorks has introduced LynxOS-178, a commercially available real-time operating system (RTOS) that meets the stringent DO-178B level A certifiable standard for safety-critical systems. The operating system originated from a partnership between Rockwell Collins and LynxWorks, with Rockwell Collins making several enhancements to the original LynxOS product and creating the Rockwell Collins' Virtual Machine Operating System (VMOS). VMOS was then certified to DO-178B level A and now the operating system and the certification artifacts are available from LynxWorks to help speed time-to-market and reduce costs for manufacturers of safety-critical products for the military and aerospace industry.

The LynxOS-178 operating system is the foundation of multiple safety-critical systems that have been certified to DO-178B, including the Bombardier Challenger 300 (primary flight display), the KC-135 (various modules) and other deployments. It implements an ARINC 653-style time partition scheduling algorithm which gives each partition fixed execution time so that the system can be deterministically safe. The system supports RTCA DO-255-compliant system partitioning which allows multiple applications of differing criticality levels within partitions to execute, completely isolated, on the same hardware resource. LynxOS-178 supports hard memory partitioning enabled by a processor MMU. Full MMU support provides the reliability advantages of protected memory and the performance advantages of hardware-mapped virtual addresses for hard partitioning between the virtual machines. With LynxOS-178, it also enables each task to run protected in its own space for uncompromising reliability within a hard partitioned virtual machine, enabling easier application certification. This added second level of granularity is not found in competitive offerings. The availability of the off-the-shelf LynxOS-178 allows developers to get products to market quickly by leveraging software and artifacts that have been certified previously. LynxWorks intends to offer a common criteria EAL7 (Evaluation Assurance Level) RTOS which will meet the international standard for developing ultra-secure software that protect systems from threats such as cyber terrorism.