Green Hills Software announced that its INTEGRITY-178 Time-Variant Unified Multi-Processing (tuMP) RTOS was selected by the U.S. Army for the operating system upgrade to the Improved Data Modem (IDM-401) program. The originally fielded IDM software functioned on a single core of its multicore CPU. This limited overall system throughput and led the IDM program to find a DO-178C DAL A compliant solution that provided optimal core utilization and greater processing power from the existing IDM multicore CPU. The primary factor in the selection of INTEGRITY-178 tuMP was the low-risk path for the delivery of its DAL A certification artifacts on a multicore architecture for the IDM processor. Other key factors included the built-in multicore interference mitigation and the ability to utilize all available cores in an efficient, optimal, and bounded manner.
The IDM-401 is the common solution for digitizing Army Aviation and is fielded on every modernized, rotary-wing Army aircraft, including the CH-47 Chinook, AH-64 Apache, and UH-60 Black Hawk. The IDM enables connectivity to multiple radios used by rotary-wing aircraft and the Blue Force Tracker transceiver, as well as providing the means for rapid data transfer. The program supports Open Systems Architecture (OSA), Future Airborne Capability Environment (FACE), and Common Operating Environment (COE) standards and interoperability.
Multicore interference is one of the biggest challenges facing avionics system integrators today. All multicore processors include some shared resources, such as memory and I/O, and interference results when access to a shared resource is blocked due to it being in use by a different processor core. This issue is of such concern that the Certification Authority Software Team (CAST) has published a position paper called CAST-32A dedicated solely to providing guidance for interference identification, mitigation, and verification in multicore systems.
The INTEGRITY-178 tuMP multicore RTOS addresses the interference challenges discussed in CAST-32A with its Bandwidth Allocation and Monitoring (BAM) capability. BAM was developed to DO-178C DAL A objectives and will mitigate the interference risks for the IDM. The INTEGRITY-178 tuMP BAM monitors and enforces the bandwidth allocation of the chip-level interconnect to each of the cores, thereby guaranteeing a particular allocation of shared resources. The supported bandwidth management technique emulates a high-rate hardware-based approach to ensure continuous allocation enforcement. This capability greatly lowers integration and certification risk while also enabling the integrator to manage significant software retest costs that would occur when a software application changes or is added. For more information, go to www.ghs.com.