LYNX MOSA.ic supports Gray Eagle UAS Software Modernization
San Jose, California, August 26, 2020 – Lynx Software Technologies, an innovator in modern...
LynxOS-178 is a native POSIX, hard real-time partitioning operating system developed and certified to FAA DO-178B/C DAL A safety standards. It is the only Commercial-off-the-Shelf (COTS) OS to be awarded a Reusable Software Component (RSC) certificate from the FAA for re-usability in DO-178B/C certification projects.
LynxOS-178 is the primary host for real-time POSIX and FACE™ applications within the LYNX MOSA.ic™ development and integration framework. LynxOS-178 native POSIX implementation satisfies the PSE 53/54 profiles for both dedicated and multi-purpose real-time as well as FACE™ applications.
LynxOS and LynxOS-178 have been deployed in millions of safety-critical applications worldwide, including multiple military and aerospace systems.
LynxOS-178 is a COTS RTOS supporting x86, Arm, and PowerPC platforms. It is based on open standards and is designed specifically to fulfill the stringent needs of multithread and multiprocess applications in safety-critical real-time systems, providing security and safety through strict, hardware-enforced isolation between real-time processes, applications, and the RTOS kernel services and drivers.View
The following table provides a high-level summary of various features and benefits of LynxOS-178:
|Feature||Customer Benefit||Additional Detail|
DO-178B/C Level A Reusable Certification
■ Reduced program risk
■ Shortened certification and re-certification effort
■ Incremental certification supports long-life programs over multiple technical upgrades
Reusable Software Component (RSC)
Eliminates time and cost of certification effort
First and only time and space partitioned, FAA-accepted RSC
Conformance to Open Standards
Ensures application portability, software reuse and interoperability
■ Native POSIX implementation supporting both Dedicated and Multi-purpose Real-time profiles (PSE 53/54)
■ ARINC 653-1 APplication EXecutive (APEX)
■ FACE™ 2.0 and 3.0
|Accelerates platform development and certification cycles||
Support for TCP/IP, UDP, ADP, ICMP, IGMP, FTP, PTP, Jumbo frames, segmentation /reassembly and TFTP protocols for IPv6 on a per partition basis
|Support for Arm, PowerPC and x86 Architectures||
Provides system developer with maximum flexibility to select the architecture/ chip/ supplier that best meets their requirement
|GNU C/C++ Compiler and Eclipse Toolchain Support||
Harnessing industry-standard tools reduces project costs and accelerates program development
LynxOS-178 provides previously certified software and artifacts in order to fully satisfy, right out of the box, the DO-178B/C level A requirement that every line of software in the system be verified with Modified Condition/Decision Coverage. The DO-178B/C certification process is so time- and labor-intensive that vendors may experience an output of just 125 lines of code per man-month. Testing of complex code could quickly add up to millions of dollars.
LynxOS and LynxOS-178 have been deployed in millions of safety-critical applications worldwide, including multiple military and aerospace systems certified to DO-178B/C, up to level A. LynxOS-178 is a FAA-recognized Reusable Software Component (RSC) and provides previously certified software and artifacts so that developers can speed their safety-critical systems to market. LynxOS-178 certified software provides full DO-178B/C traceability through requirements, design, code, test, and test results. Real-time systems programmers also get a boost with Lynx Software Technologies' DO-178B/C RTOS training courses.
As an FAA-recognized Reusable Software Component (RSC) that meets the objectives of RTCA/DO-178B/C, LynxOS-178 may be used on more than one project without having to regenerate certification artifacts.
LynxOS-178 RSC is more than just a set of DO-178B/C artifacts. The documentation set includes a detailed partitioning and interface analysis that focuses on time, space and resource partitioning as well as timing margin analysis so developers can allocate budgets to use operating system services. The set of RSC guidance documentation includes requirements, design data, test suites and coverage analysis to meet DO-178B/C requirements.
One of the most costly efforts of DO-178B/C level A certification is the requirements-based testing, also known as the Structural Coverage requirement. For DO-178B/C level A, the code is required to be verified with Modified Condition/Decision Coverage (MCDC), which means that every point of entry and exit in a program must have been invoked at least once in testing, every decision in the program must have taken all possible outcomes at least once, and each condition in a decision must have been shown to independently affect that decision's outcome.
LynxOS-178 satisfies the 100 percent MCDC structural coverage requirement out-of-the-box, allowing systems developers to concentrate on their applications rather than trying to get those last lines of system code exercised for system certification.
LynxOS-178 offers developers the flexibility of advanced networking features that are unmatched by the competition. The Lynx Certifiable Stack provides users with TCP/IP, UDP, ARP, ICMP, IGMP, FTP and TFTP protocols on a per partition basis certifiable up to DO-178B/C Level A. Users can configure network applications with SNMPv3 and SNTP for added flexibility. Applications can also make use of the ARINC-653 ports interface to communicate across partition boundaries. These ARINC ports can be configured on multiple hardware modules to make communication with other applications seamless.
The POSIX standards provide for communication between an application and the underlying operating system. Because POSIX conformance ensures code portability between systems, it is increasingly mandated for commercial applications and government contracts. LynxOS-178 offers POSIX.1 conformance and supplies all the services specified by POSIX 1.b (real-time extensions) and POSIX 1.c (threads extensions). The POSIX real-time and thread extensions are later additions to the original POSIX.1 standard, and they have extensive applicability for real-time and embedded systems. The real-time extensions include priority scheduling, real-time signals, clocks and timers, semaphores, message passing, shared memory, asynch and synch I/O, and memory locking. The threads extensions include specifications for thread creation, control, and cleanup; thread scheduling; thread synchronization; and signal handling.
LynxOS-178 conforms to the ARINC 653-1 Application Executive Software (APEX) Interface defined by the ARINC 653-1 standard and provides the following system service groups in accordance with the ARINC 653-1 standard:
ARINC 653 Intrapartition Communication: services responsible for communication between processes residing in the same partition. There are four types of Intrapartition Communication service requests:
Event Services: An event is a synchronization object used to notify the occurrence of a condition to processes that may wait for it. CREATE_EVENT and SET_EVENT are Event Services service requests.
ARINC 653 Health Monitoring: The Health Monitor (HM) is invoked by an application calling the RAISE_APPLICATION_ERROR service or by the OS or hardware detecting a fault. LynxOS-178 achieves system security through Virtual Machine (VM) brick-wall partitions of time, memory and resources. Real-time systems programmers get a boost with Lynx Software Technologies' DO-178B/C RTOS training courses.
Each RTOS partition performs like a stand-alone real-time operating system. System events in one RTOS partition can neither share resources nor interfere with events in another RTOS partition (except for "VM0," a partition with special root privileges).The DO-255-compliant system partitioning allows secure RTOS execution of applications of various DO-178B/C criticality levels—concurrently—in different partitions on the same processor, according to the needs of the product. For example, the OS can run a DO-178B/C level A application in one VM while a level C application is running in another. The LynxOS-178 RTOS partitioning involves exclusive access of three kinds: time, memory and resources.
Time partitioning is done through a fixed-cyclic time-slice scheduler, which allocates periods of time to each partition. During each time slice, only processes in the assigned partition are permitted to execute. LynxOS-178 implements an ARINC 653-1-based time partition scheduling algorithm that gives each partition fixed execution time so that the system can be deterministically safe.
Memory partitioning is achieved by dividing RAM into discrete blocks of non-overlapping physical address space. Each RTOS partition is assigned one and only one block of memory. Within the partition, the virtual address spaces of various processes are mapped to memory from the assigned memory block.
Resource partitioning means that each device can be assigned to only one partition of the RTOS. This means that a fault in a device or its driver will be contained within a single RTOS partition. Each partition mounts a RAM-based file system for data storage. The file systems are private to the individual partitions and are never shared with other partitions.
We want our customers to buy what they need—and only what they need. Real-time operating systems can provide a tremendous amount of value, but they are NOT required for every embedded system design. The guide linked to the button below, "How Choose an RTOS," is meant to help those who know they need a real-time operating system for the embedded system design.
For a more complete listing of our RTOS-related resources, visit our Embedded Systems Learning Center, which is filled with helpful material for making software purchase decisions as you design or update your system and consider which real-time platform vendor is right for you.
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