Concept
Zephyr (ˈzɛf_ər) is a small real-time operating system (RTOS) for connected, resource-constrained and embedded devices (with an emphasis on microcontrollers) supporting multiple architectures and released under the Apache License 2.0. Zephyr includes a kernel, and all components and libraries, device drivers, protocol stacks, s, and firmware updates, needed to develop full application software. Zephyr originated from Virtuoso RTOS for digital signal processors (DSPs). In 2001, Wind River Systems acquired Belgian software company Eonic Systems, the developer of Virtuoso. In November 2015, Wind River Systems renamed the operating system to Rocket, made it open-source and royalty-free. Compared to Wind River's other RTOS, VxWorks, Rocket had a much smaller memory needs, especially suitable for sensors and single-function embedded devices. Rocket could fit into as little as 4 KB of memory, while VxWorks needed 200 KB or more. In February 2016, Rocket became a hosted collaborative project of the Linux Foundation under the name Zephyr. Wind River Systems contributed the Rocket kernel to Zephyr, but still provided Rocket to its clients, charging them for the cloud services. As a result, Rocket became "essentially the commercial version of Zephyr". Since then, early members and supporters of Zephyr include Intel, NXP Semiconductors, Synopsys, Linaro, Texas Instruments, DeviceTone, Nordic Semiconductor, Oticon, and Bose. Zephyr had the largest number of contributors and commits compared to other RTOSes (including Mbed, RT-Thread, NuttX, and RIOT). Zephyr intends to provide all components needed to develop resource-constrained and embedded or microcontroller-based applications. This includes, but is not limited to: A small kernel A flexible configuration and build system for compile-time definition of required resources and modules A set of protocol stacks (IPv4 and IPv6, Constrained Application Protocol (CoAP), LwM2M, MQTT, 802.15.
