Microsoft buys Express Logic and its real-time OS for the IoT

In case you still had hope for Windows making some dramatic turnaround, creating a stripped-down version for low-power IoT devices, the writing should have been on the wall for you back when the firm unveiled its Azure Sphere Linux OS. So, if you needed any more convincing that Windows was not for the IoT, Microsoft’s purchase of Express Logic and its ThreadX real-time operating system (RTOS) should really drive the point home.

Express Logic is a 23-year old firm, operating out of San Diego. It claims that its ThreadX RTOS has 6.2bn deployments globally, to date, which will clue you in on the type of device that requires an RTOS. Typically, these are microcontroller-powered devices, which use MCUs that have very small memory and compute resources. To this end, RTOSs are very lean, but are also quite scalable. They can power MCUs with just a few kilobytes of memory, all the way up to things like industrial controllers that power machinery.

As the name implies, RTOS systems require real-time data processing, and so they are designed to provide guaranteed process delivery time – that is, a guarantee for how long it takes to act on an input and deliver the output. The design prioritizes this speed, rather than the compute horsepower and throughput. Because of the architecture’s design, it is used in systems that have very little or even no tolerance for execution failures.

This is at the other end of the scale that Microsoft is currently most busy in, that is the cloud computing sector. However, the cloud is essentially the great translating layer for the IoT, and so any device that generates data packets and can be connected to the internet in some fashion can feasibly talk to any connected system in the world. To this end, any improvement in how an RTOS-powered device goes about doing this could be beneficial to Microsoft’s Azure strategy.

“With this acquisition, we will unlock access to billions of new connected endpoints, grow the number of devices that can seamlessly connect to Azure and enable new intelligent capabilities,” said Microsoft’s director of IoT Sam George. “Express Logic’s ThreadX RTOS joins Microsoft’s growing support for IoT devices and is complementary with Azure Sphere, our premier security offering in the microcontroller space.”

Azure Sphere is a three-pronged approach, starting at the chip itself, with a new family of microcontrollers (MCUs). The chips are intended to provide hardware-based security, through secure enclaves for handling encryption keys, as well as the real-time and application processor requirements. It seems like these are meant to be standalone chips, to power devices, not add-ons or augmentations.

The next step up is the Azure Sphere OS, which is actually based on Linux – quite a departure for Microsoft. The company says that Azure Sphere OS houses a custom Linux kernel, as well as security innovations that were ‘pioneered in Windows,’ to provide a highly secure software environment to run trustworthy IoT devices and experiences.

The move to being more Linux friendly came into being after CEO Satya Nadella took charge. There has been a subtle rebranding of the cloud platform, shifting it from Windows Azure to Microsoft Azure, and parts of Windows itself have been opened up to Linux.

The final component is the Azure Sphere Security Service, the cloud-based component that will be brokering the device-to-device and device-to-cloud relationships. It will be using all the data collected from Azure Sphere deployments to spot emerging security threats.

So, ThreadX is now going to be available as an alternative to Azure Sphere OS, for the Microsoft-approved MCUs that will then tie-in with the rest of the Azure ecosystem – which is growing by the day. It is unclear if Microsoft would begin cutting support for designs that are not part of its Azure Sphere family, as that would certainly rub against its current attempts to portray itself as a company that is open to collaboration and open source.

“Effective immediately, our ThreadX RTOS and supporting software technology, as well as our talented engineering staff, join Microsoft,” Express Logic CEO William Lamie said in a statement. “We are thankful and humbled by our customers’ loyalty and support. The significant growth of the IoT provides exciting new opportunities for our customers and the embedded market overall. Now as part of Microsoft, we believe our customers will be even better positioned to unlock exciting new capabilities of the IoT.”

ThreadX is one of the more prominent RTOS flavors in the market. BlackBerry’s QNX is another that many will have heard of, and Wind River’s VxWorks is another. Wind River was recently ditched by Intel, sold off to a private equity firm for what was probably a pittance. Zephyr is another recognizable RTOS, as are FreeRTOS (which is now under Amazon’s stewardship) and Arm’s Mbed OS, and new designs appear quite regularly – with Apache’s MyNewt, Riot OS, and Contiki being pretty interesting from an IoT perspective.