Contiki is an

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 ...

for networked, memory-constrained systems with a focus on low-power wireless

Internet of Things The Internet of things (IoT) describes physical objects (or groups of such objects) with sensors, processing ability, software and other technologies that connect and exchange data with other devices and systems over the Internet or other comm ...

(IoT) devices. Extant uses for Contiki include systems for

street lighting A street light, light pole, lamp pole, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road or path. Similar lights may be found on a railway platform. When urban electric power distribution ...

, sound monitoring for

smart cities A smart city is a technologically modern urban area that uses different types of electronic methods and sensors to collect specific data. Information gained from that data is used to manage assets, resources and services efficiently; in return ...

radiation monitoring Radiation monitoring involves the measurement of radiation dose or radionuclide contamination for reasons related to the assessment or control of exposure to radiation or radioactive substances, and the interpretation of the results. Environment ...

, and alarms.. It is

open-source software Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Op ...

released under the BSD-3-Clause license. Contiki was created by

Adam Dunkels Adam Dunkels (born 1978) is a Swedish computer scientist, computer programmer, entrepreneur, and founder of Thingsquare, an Internet of things (IoT) product development business. His father was professor of mathematics Andrejs Dunkels. His moth ...

in 2002 and has been further developed by a worldwide team of developers from Texas Instruments, Atmel, Cisco, ENEA,

ETH Zurich (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , ac ...

, Redwire,

RWTH Aachen University RWTH Aachen University (), also known as North Rhine-Westphalia Technical University of Aachen, Rhine-Westphalia Technical University of Aachen, Technical University of Aachen, University of Aachen, or ''Rheinisch-Westfälische Technische Hoch ...

, Oxford University, SAP, Sensinode,

Swedish Institute of Computer Science RISE SICS (previously Swedish Institute of Computer Science) is a leading research institute for applied information and communication technology in Sweden, founded in 1985. It explores the digitalization of products, services and businesses. In ...

, ST Microelectronics, Zolertia, and many others. Contiki gained popularity because of its built in TCP/IP stack and lightweight preemptive scheduling over event-driven kernel which is a very motivating feature for IoT. The name ''Contiki'' comes from

Thor Heyerdahl Thor Heyerdahl KStJ (; 6 October 1914 – 18 April 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany and geography. Heyerdahl is notable for his ''Kon-Tiki'' expedition in 1947, in which he sailed 8,000&nb ...

's famous

Kon-Tiki The ''Kon-Tiki'' expedition was a 1947 journey by raft across the Pacific Ocean from South America to the Polynesian islands, led by Norwegian explorer and writer Thor Heyerdahl. The raft was named ''Kon-Tiki'' after the Inca god Viracocha, for ...

raft. Contiki provides multitasking and a built-in

Internet Protocol Suite The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

(TCP/IP stack), yet needs only about 10

kilobyte The kilobyte is a multiple of the unit byte for digital information. The International System of Units (SI) defines the prefix ''kilo'' as 1000 (103); per this definition, one kilobyte is 1000 bytes.International Standard IEC 80000-13 Quantiti ...

s of

random-access memory Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to b ...

(RAM) and 30 kilobytes of

read-only memory Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM cannot be electronically modified after the manufacture of the memory device. Read-only memory is useful for storing sof ...

(ROM). A full system, including a

graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

, needs about 30 kilobytes of RAM. A new branch has recently been created, known a
Contiki-NG
The OS for Next Generation IoT Devices

Hardware

Contiki is designed to run on types of hardware devices that are severely constrained in

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...

power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...

, processing power, and communication

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

. A typical Contiki system has memory on the order of kilobytes, a power budget on the order of milliwatts, processing speed measured in megaHertz, and communication bandwidth on the order of hundreds of kilobits/second. Such systems include many types of

embedded system 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, and old

8-bit In computer architecture, 8-bit Integer (computer science), integers or other Data (computing), data units are those that are 8 bits wide (1 octet (computing), octet). Also, 8-bit central processing unit (CPU) and arithmetic logic unit (ALU) arc ...

computers.

Networking

Contiki provides three network mechanisms: the uIP TCP/IP stack, which provides

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 ...

networking, the uIPv6 stack, which provides

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 ...

networking, and the Rime stack, which is a set of custom lightweight networking protocols designed for low-power wireless networks. The IPv6 stack was contributed by Cisco and was, when released, the smallest IPv6 stack to receive the ''IPv6 Ready'' certification. The IPv6 stack also contains the ''Routing Protocol for Low power and Lossy Networks'' (RPL) routing protocol for low-power lossy IPv6 networks and the

6LoWPAN 6LoWPAN (acronym of "IPv6 over Low-Power Wireless Personal Area Networks") in '6LoWPAN: The Embedded Internet', Shelby and Bormann redefine the 6LoWPAN acronym as "IPv6 over lowpower wireless area networks," arguing that "Personal" is no longer rel ...

header compression and adaptation layer for

IEEE 802.15.4 IEEE 802.15.4 is a technical standard which defines the operation of a low-rate wireless personal area network (LR-WPAN). It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, ...

links. Rime is an alternative network stack, for use when the overhead of the IPv4 or IPv6 stacks is prohibitive. The Rime stack provides a set of communication primitives for low-power wireless systems. The default primitives are single-hop unicast, single-hop broadcast, multi-hop unicast, network flooding, and address-free data collection. The primitives can be used on their own or combined to form more complex protocols and mechanisms.

Low-power operation

Many Contiki systems are severely power-constrained. Battery operated wireless sensors may need to provide years of unattended operation and with little means to recharge or replace batteries. Contiki provides a set of mechanisms to reduce the power consumption of systems on which it runs. The default mechanism for attaining low-power operation of the radio is called ContikiMAC. With ContikiMAC, nodes can be running in low-power mode and still be able to receive and relay radio messages.

Simulation

The Contiki system includes a sensor simulator called Cooja, which simulates of Contiki nodes. The nodes belong to one of the three following classes: a) emulated Cooja nodes, b) Contiki code compiled and executed on the simulation host, or c) Java nodes, where the behavior of the node must be reimplemented as a Java class. One Cooja simulation may contain a mix of sensor nodes from any of the three classes. Emulated nodes can also be used to include non-Contiki nodes in a simulated network. In Contiki 2.6, platforms with the

TI MSP430 The MSP430 is a mixed-signal integrated circuit, mixed-signal microcontroller family from Texas Instruments, first introduced on 14 February 1992. Built around a CPU, the MSP430 is designed for low cost and, specifically, low power consumptio ...

and

Atmel AVR AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. These are modified Harvard architecture 8-bit Reduced instruction set computer, RISC single-chip microcontrollers. AVR was one of the f ...

microcontrollers can be emulated.

Programming model

To run efficiently on small-memory systems, the Contiki programming model is based on

protothreads A protothread is a low-overhead mechanism for concurrent programming. Protothreads function as stackless, lightweight threads, or coroutines, providing a blocking context cheaply using minimal memory per protothread (on the order of single bytes) ...

. A protothread is a memory-efficient programming abstraction that shares features of both multithreading and

event-driven programming In computer programming, event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions ( mouse clicks, key presses), sensor outputs, or message passing from other programs or t ...

to attain a low memory overhead of each protothread. The kernel invokes the protothread of a process in response to an internal or external event. Examples of internal events are timers that fire or messages being posted from other processes. Examples of external events are sensors that trigger or incoming packets from a radio neighbor. Protothreads are cooperatively scheduled. Thus, a Contiki process must always explicitly yield control back to the kernel at regular intervals. Contiki processes may use a special protothread construct to block waiting for events while yielding control to the kernel between each event invocation.

Features

Contiki supports per-process optional preemptive multithreading,

inter-process communication In computer science, inter-process communication or interprocess communication (IPC) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categori ...

using message passing through events, as well as an optional

(GUI) subsystem with either direct graphic support for locally connected terminals or networked virtual display with

Virtual Network Computing Virtual Network Computing (VNC) is a graphical desktop-sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer. It transmits the keyboard and mouse input from one computer to another, relaying the g ...

(VNC) or over Telnet. A full installation of Contiki includes the following features: * Multitasking kernel * Optional per-application

preemptive multithreading In computing, preemption is the act of temporarily interrupting an executing task, with the intention of resuming it at a later time. This interrupt is done by an external scheduler with no assistance or cooperation from the task. This preempt ...

Protothreads A protothread is a low-overhead mechanism for concurrent programming. Protothreads function as stackless, lightweight threads, or coroutines, providing a blocking context cheaply using minimal memory per protothread (on the order of single bytes) ...

(TCP/IP) networking, including

Windowing system In computing, a windowing system (or window system) is software that manages separately different parts of display screens. It is a type of graphical user interface (GUI) which implements the WIMP (windows, icons, menus, pointer) paradigm for ...

and GUI * Networked remote display using

* A

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

(claimed to be the world's smallest) * Personal

web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...

* Simple

telnet Telnet is an application protocol used on the Internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control i ...

client *

Screensaver A screensaver (or screen saver) is a computer program that blanks the display screen or fills it with moving images or patterns when the computer has been idle for a designated time. The original purpose of screensavers was to prevent phosphor ...

Contiki is supported by popular

SSL/TLS Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securi ...

libraries such as

wolfSSL wolfSSL is a small, portable, embedded SSL/TLS library targeted for use by embedded systems developers. It is an open source implementation of TLS (SSL 3.0, TLS 1.0, 1.1, 1.2, 1.3, and DTLS 1.0, 1.2, and 1.3) written in the C programming lan ...

, which includes a port in its 3.15.5 release.

Ports

The Contiki operating system is ported to the following systems:

Microcontrollers

Atmel Atmel Corporation was a creator and manufacturer of semiconductors before being subsumed by Microchip Technology in 2016. Atmel was founded in 1984. The company focused on embedded systems built around microcontrollers. Its products included micr ...

–

ARM In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between the ...

, AVR *

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 ...

– LPC1768, LPC2103
MC13224
*

Microchip An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny M ...

– dsPIC, PIC32 (PIC32MX795F512L) *

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 ...

–

MSP430 The MSP430 is a mixed-signal microcontroller family from Texas Instruments, first introduced on 14 February 1992. Built around a CPU, the MSP430 is designed for low cost and, specifically, low power consumption embedded applications. Applic ...

, CC2430
CC2538CC2630, CC2650CC2538cctvFireflyZoul
(comprises the CC2538 and CC1200 in a single module format) *

STMicroelectronics STMicroelectronics N.V. commonly referred as ST or STMicro is a Dutch multinational corporation and technology company of French-Italian origin headquartered in Plan-les-Ouates near Geneva, Switzerland and listed on the French stock market. ST ...

– STM32 W

Computers

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

– II series

cc65 cc65 is a cross development package for 6502 and 65C02 targets, including a macro assembler, a C cross compiler, linker, librarian and several other tools. Overview cc65 is based on a native C compiler that was originally adapted for the Atar ...

based development *

Atari Atari () is a brand name that has been owned by several entities since its inception in 1972. It is currently owned by French publisher Atari SA through a subsidiary named Atari Interactive. The original Atari, Inc. (1972–1992), Atari, Inc., ...

–

, ST,

Portfolio Portfolio may refer to: Objects * Portfolio (briefcase), a type of briefcase Collections * Portfolio (finance), a collection of assets held by an institution or a private individual * Artist's portfolio, a sample of an artist's work or a ...

Casio is a Japanese multinational electronics manufacturing corporation headquartered in Shibuya, Tokyo, Japan. Its products include calculators, mobile phones, digital cameras, electronic musical instruments, and analogue and digital watches. It ...

–

Pocket Viewer Pocket Viewer (Casio PV) was a model range of personal digital assistants (PDAs) developed by Casio around the turn of the 21st Century. Description Pocket Viewer was a model range of PDAs from Casio. Early models used Intel x86 based processor ...

Commodore Commodore may refer to: Ranks * Commodore (rank), a naval rank ** Commodore (Royal Navy), in the United Kingdom ** Commodore (United States) ** Commodore (Canada) ** Commodore (Finland) ** Commodore (Germany) or ''Kommodore'' * Air commodore, a ...

–

PET A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...

VIC-20 The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit home computer that was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PE ...

, 64, 128 *

Tangerine Computer Systems Tangerine Computer Systems was a British microcomputer company founded in 1979 by Dr. Paul Johnson, Mark Rainer and Nigel Penton Tilbury in St. Ives, Cambridgeshire. The very first product was the successful TAN1648 VDU kit which received muc ...

–

Oric Oric was the name used by UK-based Tangerine Computer Systems for a series of 6502-based home computers sold in the 1980s, primarily in Europe. With the success of the ZX Spectrum from Sinclair Research, Tangerine's backers suggested a hom ...

NEC is a Japanese multinational corporation, multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It prov ...

–

PC-6001 The NEC PC-6000 series is a series of 8-bit home computers introduced in November 1981 by NEC Home Electronics. There are several models in this series, such as the PC-6001, the PC-6001 MK2 and the PC-6001 MK2 SR. There is also an American versio ...

Sharp Sharp or SHARP may refer to: Acronyms * SHARP (helmet ratings) (Safety Helmet Assessment and Rating Programme), a British motorcycle helmet safety rating scheme * Self Help Addiction Recovery Program, a charitable organisation founded in 19 ...

– Wizard *

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 ...

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

VIA Via or VIA may refer to the following: Science and technology * MOS Technology 6522, Versatile Interface Adapter * ''Via'' (moth), a genus of moths in the family Noctuidae * Via (electronics), a through-connection * VIA Technologies, a Taiwan ...

, many others –

x86 x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introd ...

-based

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems, atop

GTK+ GTK (formerly GIMP ToolKit and GTK+) is a free and open-source cross-platform widget toolkit for creating graphical user interfaces (GUIs). It is licensed under the terms of the GNU Lesser General Public License, allowing both free and proprie ...

, or more directly using an

X Window System The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems. X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wit ...

Game consoles

* Atari –

Jaguar The jaguar (''Panthera onca'') is a large cat species and the only living member of the genus '' Panthera'' native to the Americas. With a body length of up to and a weight of up to , it is the largest cat species in the Americas and the th ...

Game Park Game Park was a South Korean company that was founded in 1996 and went bankrupt in March 2007. It is responsible for creating the GP32 and the never-released XGP. GamePark Holdings was founded by former employees of Game Park in 2005. Foundatio ...

–

GP32 The GP32 (GamePark 32) is a handheld game console developed by the South Korean company Game Park. It was released on November 23, 2001, in South Korea and distributed in some parts of Europe. History The GP32 was shown at E3 in 1999, 2000, 2001 ...

Nintendo is a Japanese Multinational corporation, multinational video game company headquartered in Kyoto, Japan. It develops video games and video game consoles. Nintendo was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produce ...

–

Game Boy The is an 8-bit fourth generation handheld game console developed and manufactured by Nintendo. It was first released in Japan on April 21, 1989, in North America later the same year, and in Europe in late 1990. It was designed by the same ...

Game Boy Advance The (GBA) is a 32-bit handheld game console developed, manufactured and marketed by Nintendo as the successor to the Game Boy Color. It was released in Japan on March 21, 2001, in North America on June 11, 2001, in the PAL region on June 22, 2 ...

, Entertainment System (NES) * NEC –

TurboGrafx-16 The TurboGrafx-16, known as the outside North America, is a home video game console designed by Hudson Soft and sold by NEC, NEC Home Electronics. It was the first console marketed in the fourth generation of video game consoles, fourth genera ...

Entertainment SuperSystem (PC Engine)

Notes

References

* : unofficial website for historic ports of the 1.x version. * . * . * .

External links

* * * {{Real-time operating systems Embedded operating systems Free web browsers Free software operating systems TRS-80 Color Computer Commodore 64 software Commodore 128 software Apple II software Atari 8-bit family software Atari ST software VIC-20 software ARM operating systems MIPS operating systems Software using the BSD license