Microsoft today announced that it’s acquired Express Logic, a 23-year-old San Diego, California-based developer of real-time operating systems (RTOS) for internet of things (IoT) and edge devices powered by microcontroller units (MCUs), for an undisclosed amount.

The Seattle company notes that Express Logic’s ThreadX RTOS — which is designed to scale from resource-constrained, battery-powered devices with less than 64KB of flash memory to much more powerful hardware — has over 6.2 billion deployments, making it one of the most-deployed RTOS in the world.

“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,” wrote Microsoft’s director of IoT Sam George in a blog post. “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.”

The goal is to make ThreadX RTOS available as an option for real-time processing requirements on an Azure Sphere device, Microsoft says, and to enable ThreadX-powered devices to connect to Azure IoT Edge devices when the IoT solution calls for edge computing capabilities. (For the uninitiated, Sphere comprises a set of certified and secured third-party MCUs made by hardware partners like MediaTek, a Linux-based operating system, and a cloud-based security and management service.)

“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.”

In addition to Azure Sphere, Microsoft’s rich ecosystem of IoT products includes Azure Digital Twins, Azure IoT Edge, Azure Maps and Azure IoT Central. Separately, it’s partnered with companies like DJI, SAP, PTC, Qualcomm, and Carnegie Mellon University for IoT and edge app development.

Microsoft last April said that it intends to set aside $5 billion in IoT and the intelligent edge over the next four years, a substantial uptick from the $1.5 billion it spent on those initiatives prior to 2018. It’s an investment that’s likely to pay dividends — by 2020, Gartner predicts there will be more than 20 billion connected devices, and it’s estimated that 9 billion MCU-powered devices are built and deployed globally every year.