Microsoft built its own custom Linux kernel for its new IoT service

At a small press event in San Francisco, Microsoft today announced the launch of a secure end-to-end IoT product that focuses on microcontroller-based devices — the kind of devices that use tiny and relatively low-powered microcontrollers (MCUs) for basic control or connectivity features. Typically, these kinds of devices, which could be anything from a toy to a household gadget or an industrial application, don’t often get updated and hence, security often suffers.

At the core of Azure Sphere is a new class of certified MCUs. As Microsoft president and chief legal officer Brad Smith stressed in today’s announcement, Microsoft will license these new Azure Sphere chips for free, in hopes to jump-start the Azure Sphere ecosystem.

Because it’s hard to secure a device you can’t update or get telemetry from, it’s no surprise that these devices will feature built-in connectivity. And with that connectivity, these devices can also connect to the Azure Sphere Security Service in the cloud.

Now, you probably assume that these devices will run Windows, but you’re wrong. For the first time ever, Microsoft is launching a custom Linux kernel and distribution: the Azure Sphere OS. It’s an update to the kind of real-time operating systems that today’s MCUs often use.

Why use Linux? “With Azure Sphere, Microsoft is addressing an entirely new class of IoT devices, the MCU,” Rob Lefferts, Microsoft’s partner director for Windows enterprise and security told me at the event.” Windows IoT runs on microprocessor units (MPUs) which have at least 100x the power of the MCU. The Microsoft-secured Linux kernel used in the Azure Sphere IoT OS is shared under an OSS license so that silicon partners can rapidly enable new silicon innovations.” And those partners are also very comfortable with taking an open-source release and integrating that with their products.

To get the process started, MediaTek is producing the first set of these new MCUs. These are low-powered, single-core ARM-A7 systems that run at 500MHz and include WiFi connectivity as well as a number of other I/O options.

As far as the open ecosystem goes, Smith also stressed that the devices can be used with services that run on any other cloud, no matter whether that’s AWS or the Alibaba Cloud.

Interestingly, Amazon’s AWS unit announced a somewhat similar project at its re:Invent conference last year. It’s probably no surprise that these large cloud providers are interested in MCUs, given that while the devices themselves are not bound to any cloud, the only way to get the full value out of them is in combination with cloud services, whether that’s for authenticating new devices, updating operating systems or managing the software that runs on them.