Deos supports popular avionics standards and other features allowing users to customize their Deos environment by choosing from a variety of optional modules:

  • RTCA DO-178C/EUROCAE ED-12C Verification Evidence (Artifacts) to Design Assurance Level A (DAL A)
  • FAA/EASA A(M)C 20-193
  • ARINC Specification 653 Part 1
  • ARINC Specification 653 Part 4
  • The Open Group Future Airborne Capability Environment®, also known as, FACE® Consortium
  • POSIX 1003.1 subset targeted at FACE Safety Extended and Safety Base Profiles
  • DVMS (Deos Volume Management System) with exFAT File System
  • CFFS (Certifiable Fast File System)
  • ARINC-615 Target Data Loader
  • ARINC-664 Data Bus
  • AFDX

RTCA DO-178C/EUROCAE ED-12C  – Deos’ development began in 1995 and it has been developed with complete verification evidence to the guidance of DO-178 since the development of requirements for the first line of software. Deos was first audited to Design Assurance Level A (DAL A) during the certification of the Bombardier Global Express in 1998 and since that first deployment it has been used as a platform for dozens of avionics functions and is flying on 10’s of thousands of aircraft worldwide.

FAA/EASA A(M)C 20-193 – Deos’s innovative SafeMC and Cache Partitioning technologies for multicore processors best addresses the FAA/EASA A(M)C 20-193 objectives for minimizing and bounding multi-core interference.

ARINC-653 – Deos optionally supports the ability to run applications written to conform to the ARINC 653 Standard.  ARINC 653 is an Avionics Application Standard Software Interface specification for space and time partitioning in safety-critical avionics that defines an API called APplication EXecutive (APEX). It allows the hosting of multiple applications of different software levels on  the  same  hardware  in the  context  of an  Integrated  Modular Avionics architecture.  As shown in the figure above ARINC 653 applications can coexist with both Deos RMA processes and POSIX Processes as the ARINC 653 Partitions and Tasks are mapped within a Deos Partition.  Deos’s optional ARINC 653 package supports: the complete Part 1 Supplement 3; the File System, Memory Blocks, and Sampling Port Extensions of the optional services defined in Part 2 ; the complete Part 4 specification. DDC-I also offers certification artifacts to DO-178C DAL A for this optional package.

FACE® Interfaces – The Open Group Future Airborne Capability Environment (FACE) Consortium has developed a reference architecture and standard for real-time embedded avionics systems. The FACE Technical Standard defines required capabilities for real-time operating systems (RTOS),  I/O services, transport services, and a shared data model. RTOS requirements specified by the FACE Operating System Segment are based on ARINC 653 and POSIX 1003.1b subset tailored to address the needs of avionics systems.

POSIX Interfaces for FACE, DDC-I para-virtualized RTEMS (an open-source POSIX RTOS) to leverage its strengths in functionality and pedigree.   RTEMS was originally released in 1990 as a deterministic real-time environment and is employed in military, space, and some industrial applications.  Integrating a para-virtualized RTEMS with Deos combines the strengths of both OSs and provides a path to conformance with the FACE Technical Standard Safety Extended and Safety Base operating system profiles and maximum portability of standards-based applications software.

RTEMS on Deos delivers efficient execution within a Deos partition, which provides the required operating system services to RTEMS.  This allows RTEMS to execute in user space with its normal critical sections, proper memory layout, and only interfaces with the Deos kernel for timing and I/O.  POSIX applications on RTEMS therefore will be partitioned and will be provided the I/O services needed by the Deos kernel.

Deos Volume Management System (DVMS) – Deos contains DO-178 DAL-A kernel file systems, which are read-only during in-flight use. The optional DVMS exFAT file system provides a rich feature set that permits a read/write capability in-flight.   DVMS is well suited for both systems with very large data storage requirements, and also applications with high performance, low latency, and random access read/write file requirements.  Additionally, by using the exFAT format, a standard file system format for high-capacity memory devices, data can be easily transferred on or off the Deos based system through removable media supporting exFAT onto Linux or Windows based PCs.  Certification artifacts to DO-178C DAL A are available for this optional package.

Certifiable Fast File System (CFFS) – The optional CFFS provides a rich feature set that also permits read/write capability in-flight. CFFS was designed for systems requiring low latency and very high transfer rates for data streaming types of applications.  Typical CFFS applications include Logging Aircraft Monitoring Data or Displays for Image and Graphic Data.  Certification artifacts to DO-178C DAL A are available for this optional package.

ARINC-615A Target Data Loader – Avionics systems require the ability to transfer the initial software load to the hardware as well as update this software load in the field.  The ability to transfer this software or data with an avionics device running Deos™ may be carried out through the optional Deos Target Data Loader (TDL) software package that supports the ARINC 615A standard. The ARINC 615A protocol is referred to as the Data Load Protocol (DLP) and it specifies the communications between an ARINC 615A Data Loader, which can be any computer with a network interface such as Ethernet/AFDX/ARINC 664 and the avionics target device (in this case an avionics device running Deos and the TDL software package). DO-178 certification artifacts to DAL A are available for the TDL integrity library.

ARINC-664/AFDX Driver Library – Deos includes an industry standard lightweight TCP/IP stack (LwIP) with a DAL-A sockets library so it can provide data transport during in flight or on ground as part of its standard package.  While it may have high data integrity (e.g., through CRC or other such mechanisms), TCP/IP over Ethernet is a non-deterministic protocol.  As such, it is not suitable for some avionics applications.  In contrast, ARINC-664/ADFX is a redundant and deterministic data network designed for aircraft data network applications and based on switched Ethernet technologies. These features enable ARINC-664/AFDX to be used in aircraft control and other applications where both integrity and availability are essential.  Since ARINC-664/AFDX is often employed as a data bus backbone for an aircraft, it’s also a common interface for modern aircraft monitoring and recording systems. AFDX is an ARINC 664 data network, patented by Airbus, that is a specific implementation of ARINC 664 Part 7.  DDC-I also offers certification artifacts to DO-178C DAL A for this optional package.