Zephyr is a small

real-time operating system A real-time operating system (RTOS) is an operating system (OS) for real-time applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which m ...

(RTOS) for connected, resource-constrained and

embedded device An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded'' as ...

s (with an emphasis on

microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...

s) supporting multiple architectures and released under the Apache License 2.0. Zephyr includes a

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...

, and all components and

libraries A library is a collection of materials, books or media that are accessible for use and not just for display purposes. A library provides physical (hard copies) or digital access (soft copies) materials, and may be a physical location or a vir ...

device driver In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...

protocol stack The protocol stack or network stack is an implementation of a computer networking protocol suite or protocol family. Some of these terms are used interchangeably but strictly speaking, the ''suite'' is the definition of the communication protoco ...

file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

s, and

firmware update A patch is a set of changes to a computer program or its supporting data designed to update, fix, or improve it. This includes fixing security vulnerabilities and other bugs, with such patches usually being called bugfixes or bug fixes. Patche ...

s, needed to develop full

application software Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...

History

Zephyr originated from Virtuoso RTOS for

digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on MOS integrated circuit chips. They are widely used in audio si ...

s (DSPs). In 2001,

Wind River Systems Wind River Systems, also known as Wind River (trademarked as Wndrvr), is an Alameda, California–based company, subsidiary of Aptiv PLC. The company develops embedded system and cloud software consisting of real-time operating systems software, ...

acquired Belgian software company Eonic Systems, the developer of Virtuoso. In November 2015, Wind River Systems renamed the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

to ''Rocket'', made it open-source and royalty-free. Compared to Wind River's other RTOS,

VxWorks VxWorks is a real-time operating system (or RTOS) developed as proprietary software by Wind River Systems, a wholly-owned subsidiary of Aptiv. First released in 1987, VxWorks is designed for use in embedded systems requiring real-time, determin ...

, 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 The Linux Foundation (LF) is a non-profit technology consortium founded in 2000 as a merger between Open Source Development Labs and the Free Standards Group to standardize Linux, support its growth, and promote its commercial adoption. Additi ...

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 Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

NXP Semiconductors NXP Semiconductors N.V. (NXP) is a Dutch semiconductor designer and manufacturer with headquarters in Eindhoven, Netherlands. The company employs approximately 31,000 people in more than 30 countries. NXP reported revenue of $11.06 billion in 2 ...

Synopsys Synopsys is an American electronic design automation (EDA) company that focuses on silicon design and verification, silicon intellectual property and software security and quality. Products include tools for logic synthesis and physical design ...

Linaro Linaro is an engineering organization that works on free and open-source software such as the Linux kernel, the GNU Compiler Collection (GCC), QEMU, power management, graphics and multimedia interfaces for the ARM family of instruction sets and im ...

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...

, DeviceTone,

Nordic Semiconductor Nordic Semiconductor (formerly Nordic VLSI) is a fabless semiconductor company headquartered in Trondheim, Norway, and focused on low-power wireless communications devices. Overview The company specializes in ultra-low-power performance wireless ...

Oticon Oticon is a hearing aid manufacturer based in Copenhagen, Denmark. The company is a subsidiary of the Demant Group. It was founded in 1904 by Hans Demant, whose wife was hearing impaired. The company claims to be the world's second-largest manu ...

, and

Bose Bose may refer to: * Bose (crater), a lunar crater * ''Bose'' (film), a 2004 Indian Tamil film starring Srikanth and Sneha * Bose (surname), a surname (and list of people with the name) * Bose, Italy, a ''frazioni'' in Magnano, Province of Biella ...

. , Zephyr had the largest number of contributors and commits compared to other RTOSes (including

Mbed Mbed is a platform and operating system for internet-connected devices based on 32-bit ARM Cortex-M microcontrollers. Such devices are also known as Internet of Things devices. The project is collaboratively developed by Arm and its technology p ...

, RT-Thread,

NuttX NuttX is a free and open-source Real-Time Operating System (RTOS) with an emphasis on technical standards compliance and on having a small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the main governing standards in ...

, and

RIOT A riot is a form of civil disorder commonly characterized by a group lashing out in a violent public disturbance against authority, property, or people. Riots typically involve destruction of property, public or private. The property targete ...

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: * A small kernel * A flexible configuration and build system for compile-time definition of required resources and modules * A set of protocol stacks (

IPv4 Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version de ...

and

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...

Constrained Application Protocol Constrained Application Protocol (CoAP) is a specialized Internet application protocol for constrained devices, as defined iRFC 7252 It enables those constrained devices called "nodes" to communicate with the wider Internet using similar protocols ...

(CoAP), LwM2M,

MQTT MQTT (originally an initialism of MQ Telemetry Transport) is a lightweight, publish-subscribe, machine to machine network protocol for Message queue/Message queuing service. It is designed for connections with remote locations that have devices ...

, 802.15.4, Thread,

Bluetooth Low Energy Bluetooth Low Energy (Bluetooth LE, colloquially BLE, formerly marketed as Bluetooth Smart) is a wireless personal area network technology designed and marketed by the Bluetooth Special Interest Group (Bluetooth SIG) aimed at novel applications in ...

CAN Can may refer to: Containers * Aluminum can * Drink can * Oil can * Steel and tin cans * Trash can * Petrol can * Metal can (disambiguation) Music * Can (band), West Germany, 1968 ** ''Can'' (album), 1979 * Can (South Korean band) Other * C ...

) * A virtual file system interface with several flash file systems for non-volatile storage (

FatFs FatFs is a lightweight software library for microcontrollers and embedded systems that implements File Allocation Table, FAT/exFAT file system support. Written on pure ANSI C, FatFs is platform-independent and easy to Porting, port on many hardwa ...

, LittleFS, NVS) * Management and device

mechanisms

Configuration and build system

Zephyr uses Kconfig and

devicetree In computing, a devicetree (also written device tree) is a data structure describing the hardware components of a particular computer so that the operating system's kernel can use and manage those components, including the CPU or CPUs, the memory, ...

as its configuration systems, inherited from the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...

but implemented in the programming language

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

for portability to non-

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

operating systems. The RTOS build system is based on

CMake In software development, CMake is cross-platform free and open-source software for build automation, testing, packaging and installation of software by using a compiler-independent method. CMake is not a build system itself; it generates anothe ...

, which allows Zephyr applications to be built on

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

, and

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

Kernel

Early Zephyr kernels used a dual nanokernel plus microkernel design. In December 2016, with Zephyr 1.6, this changed to a

monolithic kernel A monolithic kernel is an operating system architecture where the entire operating system is working in kernel space. The monolithic model differs from other operating system architectures (such as the microkernel architecture) in that it alone ...

. The kernel offers several features that distinguish it from other small OSes: * Single address space * Multiple scheduling algorithms * Highly configurable and modular for flexibility, with resources defined at compile-time *

Memory protection unit A memory protection unit (MPU), is a computer hardware unit that provides memory protection. It is usually implemented as part of the central processing unit (CPU). MPU is a trimmed down version of memory management unit (MMU) providing only memory ...

(MPU) based protection *

Asymmetric multiprocessing An asymmetric multiprocessing (AMP or ASMP) system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally. For example, a system might allow (either at the hardware or ope ...

(AMP, based on OpenAMP) and

symmetric multiprocessing Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all ...

(SMP) support

Security

A group is dedicated to maintaining and improving the security. Also, being owned and supported by a community means the world's open source developers are vetting the code, which significantly increases security.

References

External links

* * {{Real-time operating systems ARM operating systems Embedded operating systems Free software operating systems Linux Foundation projects Real-time operating systems Software using the Apache license

History

Features

Configuration and build system

Kernel

Security

See also

References

External links