It was just a matter of time. Microsoft has built and released its very first operating system based on Linux, not on Windows. It’s called “Azure Sphere,” and it’s a combination of software, hardware, and connectivity to provide a secure end-to-end environment for Internet of Things (IoT) devices based on tiny chips called microcontrollers (MCUs).

Usually, you’ll find this technology on household gadgets, toys, or on devices for industrial applications that don’t typically get updates.

“After 43 years, this is the first day that we are announcing — and will distribute –, a custom Linux kernel.” Microsoft President Brad Smith said during the press conference in San Francisco.

Before you start searching for “Azure Sphere OS download,” this is a software and hardware solution that comes in a chip. It’s not a piece of software that you can download and run on your computer. However, Microsoft will be licensing these new Azure Sphere chips for free.

Unlike other similar devices, because they can’t be updated or collect telemetry, these new computing devices will offer built-in connectivity and with uplink to the Azure Sphere Security Service in the cloud.

So, why Microsoft is using Linux? In part, this is because there are already many IoT devices in the market using this technology, and it’s just easier to introduce a product that partners feel more comfortable using, and it’s something that they can easily integrate with their products. Also, the version of Windows for these type of devices is just too big and resource intensive.

Rob Lefferts, Microsoft’s partner director for Windows enterprise and security says (via Techcrunch): “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.”

The first wave of Azure Sphere OS chips is being introduced by MediaTek. These MCUs are low-powered, single-core ARM-A7 computing devices running at 500MHz, Wi-Fi adapter, and other hardware options.