Azure is Microsoft’s cloud platform. It’s a platform as a service (PaaS), infrastructure as a service (IaaS), and software as a service (SaaS). For IoT and IIoT applications, Microsoft goes further with its Azure Sphere environment (Fig. 1), providing cloud support and management of IoT devices that includes gateways and end nodes.
Azure Sphere is designed to work with secure application processors like Arm’s Cortex-A family. These aren’t run-of-the-mill processors, but secure platforms that can incorporate Microsoft’s Pluton security subsystem (Fig. 2). This provides a secure root of trust for the Azure Sphere OS. Chip platforms like MediaTek’s MT3620 and NXP’s forthcoming Edge Verse i.MX8 chip family are designed to run this secure IoT operating system.
2. Azure Sphere works with secure application processors that can incorporate Microsoft's Pluton subsystem.
Azure Sphere OS is a compact version of Linux enhanced with a secure application environment that takes advantage of the underlying secure hardware. It also offers middleware and secure communication support to tie the chip to the Azure Sphere cloud.
The security support available with Azure Sphere OS is similar to SELinux and App Armor, two other Linux security modules (LSMs). Linux allows an LSM to manage application and system security. The multilayer architecture (Fig. 3) supports secure containers that bring a modular approach to application support. Container systems like Docker have become popular in the cloud and servers, and they’re equally useful in IoT end nodes.
3. The layered architecture of the Azure Sphere OS includes support for secure containers.
Azure Sphere OS is also melded with Azure Sphere support for remote management, remote updates, and IoT communication. This is all done within a secure environment. Update support covers Azure Sphere OS, Azure Sphere middleware, as well as applications.
Developers can utilize the Azure Sphere software development kit (SDK) for application development. It can streamline debugging and is supported by Microsoft’s Visual Studio IDE. Azure Sphere OS and applications also work with Azure IoT Hub asset management, Azure IoT Edge platforms, and Azure IoT Central.
Developers can get started with Azure Sphere OS using platforms like Avnet’s MT3620 Starter Kit. It’s based on MediaTek’s MT3620, which has a 500-MHz Arm Cortex-A7. It also has a pair of Arm Cortex-M4F microcontrollers for real-time support.