Avionics manufacturers are increasingly making use of the improved size, weight and power of multicore processors. The extra computational power these processors provide compared to traditional single-core processors coupled with dwindling availability of single core processors mean the aerospace industry must adapt to their use.
DO-178 guidance was created to support the development of avionics software for single-core processors. Software running on multicore processors can be subject to interference caused by contention for shared resources and other hardware idiosyncrasies that are not present in single-core processors.
Identifying the need for the aerospace industry to adopt multi-core technology, the Certification Authorities Software Team (CAST), published Position Paper “CAST-32A” in November 2016. This paper set out a series of objectives that need to be met in the SDLC to ensure that a multicore system is understood, with particular regard to timing behaviors.
The purpose of this CAST paper is to identify topics that could impact the safety, performance and integrity of a software airborne system executing on Multi-Core Processors (MCP). For each topic, the paper provides a rationale that explains why these topics are of concern and proposes objectives to address the concern.
CAST-32A Position Paper, CAST
Official CAST-32A position paper
Since the release of CAST-32A, the FAA and EASA collaborated to develop official guidance for the certification of multicore avionics software. EASA's version of this guidance, AMC (Acceptable Means of Compliance) 20-193, was released in early 2022. The FAA's version of this document (AC 20-193) is expected to be released shortly.
AMC 20-193 is very similar to CAST-32A, including the same objectives and much of the same terminology. AC 20-193 is expected to be very similar to both AMC 20-193 and CAST-32A.