How the Embedded Space is Learning to ‘Mind the Gap’

Considering solutions that stretch the life of legacy deployed equipment and those which make it possible to consolidate storage functionality and virtualization capability.

The author’s company recently exhibited at a large defense exhibition in London and having to commute into the capital by train every day for a week was a tiring yet interesting experience for an irregular commuter.

Anyone who has travelled on the London underground network will know that they are greeted at most stations with an announcement to ‘mind the gap’ when entering and leaving the train. In most cases the gap between the door and the platform is quite small but is a potential trip hazard, therefore a safety message is played. While the reason for playing the message is probably to avoid litigation in the event of an accident, it’s somewhat comforting to know that the train company has thought through every little detail and is attempting to make every journey as transparent and safe as possible.

In the embedded space we also need to “mind the gaps.” We can be very good at talking about exciting new products at the launch of new generation processor/FPGA/GPU and why these products are better/faster/smaller etc. We tend to forget that many embedded markets—especially those in the defense and transportation sectors—are pragmatically resistant to change and have a critical need to connect modern and legacy interfaces.

These legacy interfaces can be generic-based connections like standard serial ports as well as manufacturer-specific, such as those found on avionics devices. Irrespective, these are the gaps as they are no longer, or in some cases never were, an integral part of the processor chipset. It doesn’t matter how small the gap is! Without a vital feature or interface, a proposed solution doesn’t work for that customer.

This article discusses how the gaps are filled in a couple of scenarios:

  • Bridging legacy deployed equipment and modern networks
  • Consolidating storage functionality and virtualization capability into a reduced and fixed space envelope

Bridging the Old and New
To be usable deployed assets, most defense devices need to connect to an Ethernet-based network. At the same time many of the deployed legacy instruments, radios, and sensors do not have Ethernet ports, they only provide a serial port interface, which is usually RS-232/422/485. To make matters more interesting, the applications and drivers used to control and communicate with these legacy devices may only be verified on older operating systems that are not compatible with the latest computer technology.

One solution is a network enabled, multi-serial port, Intel® processor based server running Virtual Machines (VMs). Running multiple VMs on a single Intel® Xeon® processor based server reduces the actual number of physical computers, which in turn reduces the overall Size Weight and Power (SWaP) of the solution. The VMs running on the Xeon server board are connected to the network through integrated Ethernet ports. These Ethernet ports have native virtualization support whereby all the VMs can access data via the same network interfaces. In supporting existing legacy drivers and applications virtualization technology offers the benefit of being OS agnostic. Virtualization technology is also relatively easy to use with a legacy operating system like Windows XP (running as a guest inside a VM). The legacy interfaces probably won’t support virtualization, so they are only accessible from the specific VM, but that is fine as it has a bridge back to the Ethernet connection.

Vendors typically use XMC modules as the basis for adding I/O functionality as they allow for a scalable strategy. For example, one or two XMC modules can be added to a 3U or 6U processor board respectively and then further XMCs can be used on single-slot carrier boards up to the chassis capacity. One example of this approach is the Concurrent Technologies’ TR E5x/msd board. Based on the Intel® Xeon® processor E3-1500 v5 family, the TR E5x/msd board can provide a VMware capable solution with two Gigabit Ethernet ports and five RS-232/422/485 serial ports within a single 3U VPX slot. This solution is scalable up to a total of fifteen serial ports with the addition of two additional carrier and XMC modules within a SWaP advantageous 3-slot 3U VPX solution. A further step up in I/O capacity is possible by moving to a 6U form factor. The number of serial ports and networks ports doubles, so a 3-slot system can provide four Gigabit Ethernet and thirty RS-232/422/485 ports.

Saving Space but Adding Capability
The need for data storage, and more important, access to this stored data is universal and ever increasing in today’s world. This can be seen in our everyday lives and our reliance on instant access to information using our smartphone connected to the web and cloud services. All our personal smartphones, computers and, in the near future, our home appliances and our vehicles have a network connection to provide access to this data. The Internet of Things has been a hot discussion topic for a few years and even those who, like the author, are somewhat skeptical about the volume of connections and speed of the deployment cannot deny a significant increase in the number of networked devices that are generating data. The amount of data is magnified due to technology improvements in the resolution of sensors and cameras that generate ever more detailed measurements and images. In our personal world we tend to gloss over the methods used to store all this data in the cloud, although local device storage tends to become inadequate over time.

Military and aerospace applications follow the same theme. The expanding roles of unmanned platforms, intelligence, surveillance reconnaissance (ISR) missions, and new sensors all collect similarly expanding volumes of data. Further, there is a high monetary value associated with collecting the data generated within these defense applications, and the data holds strategic value, depending on the mission. To be useful from a mission objective, the collected data needs to be accessible to key users and securely stored and backed up. This is typically accomplished by a network-based file server, which provides a single location for storage and access of data.

Within military and aerospace rugged network file server applications storage read/write capability that meets the necessary throughput for sustained periods is critical. And capacity must be large enough for a complete mission. In addition, the data may have to be pre-processed using a real-time compute algorithm, plus the equipment has to be capable of operating in high/low temperatures and be immune to significant shock and vibration levels.

A Tricky Fit
A recent opportunity needed a high-performance Intel Xeon based server card that was capable of ~600 GFLOPS single precision compute performance, running many virtual machines and able to access more than 1TB of direct attached storage. Whilst this might be straightforward in a rack mount server used in a datacenter, in this case the gap was that the complete product had to fit in a single 3U VPX slot.

The solution that Concurrent Technologies proposed was based on a recent TR G4x/msd server board that supports an Intel Xeon processor with up to 16 cores, meeting the performance requirements. The number of VMs is limited, to some extent, by the amount of onboard memory. This TR G4x/msd server board has 64GB of DDR4 memory, which is fairly small compared to that in an equivalent rack mount server but is industry leading in the embedded space, where memory tends to be soldered directly to the baseboard to meet the shock and vibration exposure.

Another gap that had to be filled was sufficient file storage and server capabilities. The storage strategy is based around a SATA solid state module for the operating system and application usage of up to 128GB capacity plus two M.2 modules for data storage (both utilizing high-speed PCI Express® connectivity and NVMe protocol support). In total, up to 2TB of direct attached data storage with the option of RAID modes to increase speed/reliability was provided. For seamless integration into the network the solution included four integrated Ethernet ports; two of which operate at 10 Gigabit speeds for connection to other networked resources.

The interesting and exciting part of delivering successful solutions based on open standards is working out how to fill the gaps. Having a solution that is based on open standards is a great start, as there may be partner vendors providing modules for niche requirements. However, this doesn’t absolve the vendors of the core processing solutions from filling in gaps where they can.

Nigel Forrester is Technical Marketing Manager at Concurrent Technologies plc with responsibility for product strategy and promotion across VPX, AdvancedMC, CompactPCI and VME form factors. Forrester has previously held a number of product and vertical marketing roles in the embedded space and is an accomplished speaker and author. He has a B.Sc. (Hons.) in Computer Science and Statistics from Reading University, United Kingdom and can be contacted at

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