Military Embedded Systems

New technology innovations offer huge cost savings through software reuse


September 04, 2012

John Blevins

Lynx Software Technologies

As new systems are being designed, software developers are using open-standards-based programming languages and OSs, such as C/C++ and POSIX, to ensure portability for the future.

As new systems are being designed, software developers are using open-standards-based programming languages and OSs, such as C/C++ and POSIX, to ensure portability for the future.

But for existing deployed legacy systems, the same considerations and design methodology were not necessarily available or followed. When a refresh of the system is needed, either for a change in hardware or to add new functionality, there is often a dilemma as to how to migrate or update the existing software without having to go through the costly exercise of rewriting the software. In certified systems, this cost is even greater as recoding = recertification.

However, the good news is that a new virtualization technology enables the reuse of existing software applications, including the OSs that they run on, without having to change or rebuild the software.

Evolving legacy systems

Systems engineers today face difficult challenges when confronted with the task of evolving legacy systems based on aging hardware onto more modern equipment. When hardware fails, becomes obsolete, and is no longer available, designers must move to newer, more complex hardware. In most cases the legacy software has dependencies on an OS version that might not support the new hardware without being upgraded. The task of moving a legacy application to both a new OS and a new hardware platform can be quite costly in terms of both time and money.

This is where modern virtualization technology comes to the rescue and allows the reuse of existing software applications and their OSs with little to no code changes. Imagine a technology where a small piece of code runs directly on new modern hardware and allows multiple “guest” OSs to run concurrently on top, each with its own “virtual” set of resources (virtual machines). Each OS believes it sees a full set of hardware, complete with dedicated CPU, memory, disk, graphics, mouse, keyboard, network devices, and so on. When these virtual machines are configured to look similar to legacy hardware, it makes the task of running legacy software applications and OSs simple.

Separation kernel and hypervisor

The small piece of code that makes this possible is a Separation Kernel and Hypervisor (SKH). An SKH runs directly on the new modern hardware and allows an engineer to assign either physical or virtual resources to various guest OSs. The SKH then enforces the separation of those resources to provide hardware-level security for each guest. Legacy OSs run fully virtualized on their assigned virtual machine without any modifications. LynxSecure from LynuxWorks is an example of a highly secure, modern SKH.

In addition to the savings in redevelopment time achieved by using virtualization to run legacy applications, the SKH can also allow applications to benefit from huge performance increases. Multiple, faster CPUs and larger amounts of RAM can now be assigned to legacy OSs and applications, increasing their performance beyond anything possible with their original hardware. Moore’s Law predicts a doubling in transistor density every two years, so a 15-year-old legacy system could see an exponential (200x) increase in performance from new hardware.


Many complex military, aviation, and medical systems must undergo stringent certification processes before they can be deployed in the field. The effort to certify an application and its OS on a given hardware target can easily exceed the cost of actual development of the application itself. Virtualization can significantly reduce certification costs by allowing legacy applications and OSs to run unmodified on newer hardware. Less code changes equates to both reduced testing costs and certification reusability.

Virtualization benefits

Virtualization provides other added benefits to legacy systems. A systems engineer can now consolidate multiple legacy systems onto a single, more powerful hardware platform and reduce overall system cost. In fact, legacy systems can run alongside other newer applications and OSs to provide more functionality than before. Imagine a legacy real-time GPS application on an RTOS such as LynxOS running next to a Windows XP-based email application, all on the same hardware platform. Not only is this possible today, it can be done securely with the help of a separation kernel and hypervisor. The separation kernel guarantees that one guest cannot affect the other guests in any way. In the example provided, if the Windows XP guest picks up a “virus,” it cannot affect the RTOS guest or its performance.

Virtualization brightens legacy systems’ future

The use of a modern separation kernel and hypervisor can now add years of life into legacy systems, allowing for migration to new hardware, the addition of new features, and the consolidation of multiple physical systems into one. All these benefits help decrease costs and reduce risks when fielding new safety and security systems into the aerospace and defense industry.

John Blevins is Director of Product Marketing at LynuxWorks. He can be contacted at [email protected]


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