Deos, a Time & Space Partitioned, Multi-core Enabled, RTOS Verified to DO-178C/ED-12C DAL A

primus epic, do-178c, ARINC 653, avionics software
Primus Epic Avionics Display Application using Deos

Safety Critical RTOS for Avionics Applications requiring DO178C/ED-12C DAL A verification

Deos™, DDC-I’s safety-critical time and space partitioned real-time operating system (RTOS) that has been verified to the guidance of DO-178C/ED-12C Design Assurance Level A (DAL A) for Avionics Applications, supports ARINC 653 APEX, Rate Monotonic Scheduling (RMS), and is targeted at the Future Airborne Capability Environment (FACE™) Safety Extended and Safety Base Profiles. Deos is the first RTOS to receive OSS Conformance Certification for the FACE Technical Standard, Edition 3.1. The Safety Extended Profile, which adds support for TCP/IP communications, multi-process support, and expanded POSIX capability (80 extra functions), is a superset of the functionality required by the Safety Base and Security Profiles.

Deos has been field proven as a safety-critical RTOS since its first verification and audit to DAL A by Transport Canada in 1998, and it has been certified and is flying in 10’s of thousands of aircraft.  Since the initial verification, it has continually evolved throughout the last two decades with new processors and features in subsequent baselines, and it has been successfully audited by the world’s various governmental certification authorities (FAA, ENAC, JAA, EASA, CAAC, and others) and Airframe and Avionics Supplier Designated Engineering Representatives (DERs).

Avionics Applications using Deos

Deos has been used to manage resources and hard partition avionics applications on x86, PowerPC, ARM and MIPS microprocessors for a multitude of flight critical functions that require bounded processing, high determinism and high throughput.  These functions include: air data computers, air data inertial reference units, cockpit video, displays, flight instrumentation, electronic flight bags, engine management, enhanced ground proximity warning, FADECs, flight controls, flight management systems, maintenance systems, power distribution systems, radios, traffic collision avoidance systems(TCAS), weather radar and many more federated and IMA avionics systems.

Verified to the guidance of DO-178C/ED-12C DAL A

Deos is full featured and has been verified to DO-178C/ED-12C Design Assurance Level A (DAL A) and it addresses the issues of high robustness for avionics and safety critical applications. Deos was built from the ground up with plans and procedures created to the guidance of DO-178 starting with its requirements for its first line of code.  In fact, Deos is the only verified time and space partitioned COTS RTOS that has been created using RTCA DO-178 DAL A processes from the very first day of its product development.

Safety Critical Multi-core Operation with Industry Standard ARINC 653 APEX and POSIX APIs

Deos is multi-core enabled through its SafeMC™ Technology giving developers the ability to bound resource contention and safely schedule processes on multiple cores.  It provides the toolset for addressing the objectives of the CAST-32A Position Paper.  Deos includes ARINC 653, Rate Monotonic, and POSIX schedulers and associated standards based interfaces for maximum portability of code, and it offers several unique fundamental and patented architectural advantages over other competing  DO-178C verified safety critical RTOS’s. The result is the best performance, lowest risk, easiest to certify, and lowest cost time & space partitioned COTS RTOS for airborne avionics and safety critical applications on the market today.

Security Capabilities for Avionics Systems

Deos’ time and space partitioning, and explicit resource allocation enforcement inherently support isolation of computing and I/O resources, leading to a secure system design.  In addition, its modular boot code, hardware abstraction layer, and the availability of application program interfaces to platform hardware resources enables Deos to deliver a software foundation to easily integrate a variety of security capabilities into the avionics device.  Since system security requirements and hardware support for security functions varies on each customers target hardware platforms,  Deos is integrated with a number of 3rd party security software packages (i.e., encryption, secure networking, key management, etc.). Those packages along with a DO-178C/ED-12C verified safe and security enabled BSP (through DDC-I services, 3rd party, or customer developed) a Deos based system may be designed to meet the security requirements of most any avionics program.


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    Includes support for:

    • Linux and Windows XP, 7, 8 & 10 host development environments
    • x86, PowerPC, ARM and MIPS single- and multi-core processors
    • C, C++ (subset), Ada95 compilers
    • Rate Monotonic, ARINC 653 and POSIX scheduling and application interfaces for maximal code portability

    Popular avionics standards (DO-178C, ED-12C, ARINC, POSIX) and other optional modules:

    • DO-178C/ED-12C Verification Evidence (Artifacts) to Design Assurance Level A (DAL A)
    • ARINC 653  (ARINC Specification 653 Part 1 ) 
    • POSIX 1003.1 subset targeted at FACE Safety Extended Profile
    • ARINC 653 p4 (ARINC Specification 653 Part 4)
    • ARINC 615 (ARINC Specification 615 Target Data Loader)
    • ARINC 664 (ARINC Specification 664 Data Bus)
    • File System (ARINC Specification 653 Part 2)
    • Certifiable Fast File System – Data Streaming File System
    • AFDX – Avionics Full-Duplex Switched Ethernet