It is named after Zephyrus, the ancient Greek god of the west wind.[9]
History
Zephyr originated from Virtuoso RTOS for digital signal processors (DSPs).[10][11] 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.[11] Compared to Wind River's other RTOS, VxWorks, Rocket had 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.[11]
In February 2016, Rocket became a hosted collaborative project of the Linux Foundation under the name Zephyr.[10][12][1] Wind River Systems contributed the Rocket kernel to Zephyr, but still provided Rocket to its clients, charging them for the cloud services.[13][11] As a result, Rocket became "essentially the commercial version of Zephyr".[13]
As of January 2022[update], Zephyr had the largest number of contributors and commits compared to other RTOSes (including Mbed, RT-Thread, NuttX, and RIOT).[16]
Features
Zephyr intends to provide all components needed to develop resource-constrained and embedded or microcontroller-based applications. This includes, but is not limited to:[8]
A small kernel
A flexible configuration and build system for compile-time definition of required resources and modules
Zephyr uses Kconfig and devicetree as its configuration systems, inherited from the Linux kernel but implemented in the programming language Python for portability to non-Unix operating systems.[17] The RTOS build system is based on CMake, which allows Zephyr applications to be built on Linux, macOS, and Microsoft Windows.[18]
Utility tool "West"
Zephyr has a general-purpose tool called "west" for managing repositories, downloading programs to hardware, etc.
A group is dedicated to maintaining and improving the security.[19] Also, being owned and supported by a community means the world's open source developers are vetting the code, which significantly increases security.[12]
