Linux the popular BSP choice for PC/104 and SFF users

As Windows XP nears End Of Life (EOL), many SFF users are turning to Linux as the Board Support Package (BSP) of choice.

3PC/104 and Small Form Factor (SFF) board users - whether in military, industrial, or transportation applications - want Board Support Packages (BSPs) that are robust, low-cost, and provide long-term support. Due to its open-source nature, the Linux Operating System (OS) is meeting these requirements while running into fewer obsolescence issues. The popular OS's flexibility also helps solve challenges with ARM processor implementations.

When choosing a Board Support Package (BSP) for PC/104 products, it is essential to pick the right one out of the gate to ensure that the development process starts efficiently, and to prevent major obsolescence and costly expenses in the long term. Windows XP going End of Life (EOL), funding cuts in defense programs, and the need for a larger developer base are all driving users toward Linux, even in military applications where a Real-Time Operating System (RTOS) is the more traditional choice.

“The ability to use a standard COTS PC design lowers both software and hardware costs, while the compact ruggedized form factor allows for deployment in space-constrained hostile environments,” says John Blevins, Director of Product Marketing at LynuxWorks in San Jose, CA (www.lynuxworks.com). “Both Linux and Windows have been popular OS choices for PC/104 systems where there are no real-time requirements. Many PC/104 vendors are including Linux with their hardware at no charge, and that may appeal to a variety of customers.”

“The majority of our customers are running a version of Windows Embedded or Linux on our PC/104 products, which use x86-based processors,” says Robert A. Burckle, Vice President of Sales and Marketing at WinSystems in Arlington, TX (www.winsystems.com). “Though we provide Windows and Linux drivers for the unique functions of our products, these are not typically known as BSPs. We offer preinstalled OSs on industrial flash to get developers started quickly. This approach allows a developer to have a bootable system out of the box so they can begin testing and developing application code right away.

“Since PC/104 is traditionally PC-compatible, the BIOS and OS handles the initialization code traditionally provided in a BSP,” Burckle continues. “We do have customers that require RTOSs, and they have been very successful using the generic PC-compatible BSPs from various vendors.”

“A majority of the customers for Curtiss-Wright’s Parvus products appear to be deploying a Linux OS in our DuraCOR mission computers, so BSP requests primarily occur when VxWorks requirements surface,” says Adam Thompson, Principal Applications Engineer at Parvus Products, a Curtiss-Wright Defense Solutions company in Salt Lake City, UT (www.parvus.com). “We may also support desktop Windows and Windows Embedded OS loads.”

Linux advantages

“Linux and Free and Open-Source Software (FOSS) provide a low-cost alternative with a huge development community,” Burckle says. “For our customers, product longevity is often much more critical than the actual cost savings. Not only do they have access to the source code, they are not forced to go through a new design cycle due to licensing or EOL concerns.”

“From our vantage point, the popularity of Linux exceeds that of Windows with our DuraCOR customers, but it also seems that every customer has their own particular favorite Linux distribution, with CentOS, Red Hat, Ubuntu, Fedora, being some of the more common,” Thompson says. “But we also see ‘roll-your-own’ versions as well. Linux, in addition to bringing all the benefits that derive from having an open architecture, in many cases also provides a smaller OS image load, in terms of storage space requirements, than Windows.” Development and compiling tools are widely available for Linux and most require minimal financial investment, although some specialized distributions – for example, Wind River Linux – are exceptions.

Windows trends

The battle against obsolescence – of both hardware and software products – is probably the biggest fight engineers face in today’s electronics systems. Windows XP going EOL is a recent example, but it mostly affects the customer base of PC/104 users in the industrial world rather than in the military, as there is not much Windows use there.

“So far our customer base does not seem to be affected by Microsoft’s product lifecycles,” says Chris Douglass, Senior Software Engineer at Orion Technologies in Orlando, FL (www.oriontechnologies.com). “We see people moving toward Linux while also still choosing VxWorks for their real-time needs.”

“The majority of our customers using Windows 7 use the Embedded Standard version, which has extended support until October 2020,” WinSystems’ Burckle says. “The concern we have seen with Windows Embedded 8 is the activation process required. Since many embedded devices may not connect to the Internet directly, the activation must be handled prior to shipment. For those using full installations of Windows 7 Professional, migration to Windows 8 is expected to be relatively smooth and they will continue to get extended support into 2020.

“We currently see a nearly even split between Windows Embedded and Linux,” he continues. “The two definitely make up the lion’s share of the OS requests that we receive, though we do receive requests for Android on the ARM products. Each solution has benefits and it really depends on the customer’s requirements and their software team’s experience. Windows Embedded continues to leverage a vast network of software developers as well as stable development tools. Some of the advantages are quick time-to-market and the ability to lock down the OS so it is more secure and resistant to file system damage from an unexpected system power loss.”

ARM challenges

The flexibility of Linux also helps, along with the Android OS, in solving problems unique to the growing implementation of ARM-based solutions.

“Unlike x86 platforms, ARM BSPs require detailed information to be provided to customers concerning the tool chain configuration and processor specifics,” Burckle says. “We still take the approach of providing a preinstalled OS for Linux and Android so developers can get started quickly and have a sanity check during development. However, we also provide documentation so customers can set up a development environment similar to the one used to create the images. This allows them to further leverage the development resources. This is a major time saver for engineers new to developing for ARM products, and also provides the essentials needed by those with more experience and their own method of development.”

WinSystems recently introduced two 3.5-inch Single-Board Computers (SBCs), one based on the Freescale i.MX6 ARM processor and one based on the Intel Atom E3800 (Bay Trail-I) processor, Burckle says (Figure 1). Both provide computing, graphical, and media capabilities while operating at an extended temperature range. “The peripheral and I/O supported on the boards are similar, including the new IO60 expansion modules. These products allow designers a solution with either an x86 or ARM solution, along with the BSPs and system designer’s OS of choice,” Burckle adds.

Figure1
Figure 1: WinSystems recently introduced two 3.5-inch Single-Board Computers (SBCs) that use the IO60 expansion modules – one based on the Freescale i.MX6 ARM processor – and another based on the Intel Atom E3800 processor.

BSP choices by industry

Not every industry embraces every OS, however; unique application requirements often drive users to one particular solution, such as RTOSs being used almost exclusively for mission-critical military applications. However, Linux seems to be crossing industry boundaries.

“Many military applications using PC/104 technology are leveraging the newer PCI Express cards for networking and USB support due to the network-centric focus and situational awareness on the battlefield,” Blevins says. “Industrial applications tend to be more concerned with sensor data acquisition and motor control on production lines. Transportation applications often add GPS sensors and graphical mapping applications. However, as the Internet of Things (IoT) evolution continues to add billions of new devices to the Internet, the demand on new devices may begin to span many of these traditionally specialized industries.”

“We see Department of Defense (DoD) customers moving toward Linux because it can be supported long term and is more cost-effective than a typical RTOS,” Orion’s Douglass says. There are methods for enabling real-time functionality in a Linux-based system through partitioning, he adds. Linux has a very robust set of network capabilities and a strong set of tools that originates from the free effort behind the open-source OS, Douglass believes.

“Linux seems to have a healthy share in the [military] market,” Thompson says. “The PC/104 SBCs we have traditionally sold go into a variety of civil and military applications and they typically had Linux and Windows Embedded as their predominant OS, but we may not always know the end application. The Parvus DuraCOR mission computer product family, which integrates PC104 Intel SBCs ranging from Intel Atom to Core i7, sells with Linux CentOS and Windows 7 as standard options, with Windows Embedded and VxWorks by special order.” (See Figure 2.)

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Figure 2: (Duracor810.jpg) The Parvus DuraCOR mission computer product family sells with Linux CentOS and Windows 7 as standard options with Windows Embedded and VxWorks by special order.
(Click graphic to zoom by 1.8x)

Linux has flexibility, but some still feel the determinism and long-term support of an RTOS can’t be beat. An RTOS is usually better suited for military applications because it has the benefit of hard real-time deterministic performance, native POSIX (UNIX) APIs, as well as built-in security and safety certification features, Blevins says. “LynuxWorks is pairing LynxOS 7.0, our next-generation deterministic hard real-time operating system, with PC/104-Plus systems such as the Atom-based ADLINK CoreModule 720 SBC.”

“RTOS popularity is not exclusive to military applications, as we see customers in both industrial and transportation markets choosing VxWorks,” says Nirav Pandya, President and CEO of Orion Technologies. Like the military, these customers also require products to be in the field for as long as a decade and need the long-term support an RTOS will give them, he adds.

“Wind River’s approach to long-term support fits better than Microsoft,” says Jeff Van Anda, Vice President of Engineering at Orion Technologies, “especially when the customer has to deploy the system for decades, Wind River is more accommodating.” Orion Technologies offers the PCI7620 SBC that leverages the 4th generation Intel Core i7 for use in military, industrial, or commercial applications. It is available in commercial temperature ranges, and air-cooled to extended temperature ranges.

“We have not noticed a bias among the different industries that we serve,” Burckle says. “Each industry uses Windows, Linux, and other OSs depending on the functionality and security concerns of each specific application.”