Embedded software is computer software that plays an integral role in the electronics

Electronics

Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

 it is supplied with.

Embedded software's principal role is not Information technology

Information technology

Information technology is the acquisition, processing, storage and dissemination of vocal, pictorial, textual and numerical information by a microelectronics-based combination of computing and telecommunications...

 , but rather the interaction with the physical world. It's written for machines that are not, first and foremost, computers. Embedded software is 'built in' to the electronics in cars

CARS

Cars, or automobiles, motor cars, are wheeled motor vehicles used for transporting passengers.Cars or CARS may also refer to:-Entertainment:* Cars , a Disney/Pixar film series...

, telephones, audio equipment, robot

Robot

A robot is a mechanical or virtual intelligent agent that can perform tasks automatically or with guidance, typically by remote control. In practice a robot is usually an electro-mechanical machine that is guided by computer and electronic programming. Robots can be autonomous, semi-autonomous or...

s, appliances, toys, security systems, pacemaker

Pacemaker

An artificial pacemaker is a medical device that uses electrical impulses to regulate the beating of the heart.Pacemaker may also refer to:-Medicine:...

s, televisions and digital watches, for example. This software can become very sophisticated in applications like airplanes, missile

Missile

Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...

s, process control

Process control

Process control is a statistics and engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range...

 systems, and so on.

Embedded software is usually written for special purpose hardware: that is computer chips that are different from general purpose CPUs , sometimes using Real-time operating system

Real-time operating system

A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...

 such as LynxOS

LynxOS

The LynxOS RTOS is a Unix-like real-time operating system from LynuxWorks . Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility...

, VxWorks

VxWorks

VxWorks is a real-time operating system developed as proprietary software by Wind River Systems of Alameda, California, USA. First released in 1987, VxWorks is designed for use in embedded systems.- History :...

, Linux

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 (with patched kernel), OpenWrt

OpenWrt

OpenWrt is a Linux distribution primarily targeted at routing on embedded devices. It comprises a set of about 2000 software packages, installed and uninstalled via the opkg package management system. OpenWrt can be configured using the command-line interface of BusyBox ash, or the web interface...

, PikeOS

PikeOS

PikeOS is a microkernel-based real-time operating system made by SYSGO AG. It is targeted at safety and security critical embedded systems. It provides a partitioned environment for multiple operating systems with different design goals, safety requirements, or security requirements to coexist in a...

, eCos

ECos

eCos is an open source, royalty-free, real-time operating system intended for embedded systems and applications which need only one process with multiple threads. It is designed to be customizable to precise application requirements of run-time performance and hardware needs...

, BeRTOS

BeRTOS

BeRTOS is a real-time operating system designed for embedded systems.It is distributed under a modified GPL license with a special exception that grants proprietary applications the right to keep their source code closed while maintaining the BeRTOS code itself open.It has a very modular design,...

, ThreadX

ThreadX

ThreadX, developed and marketed by Express Logic, Inc. of San Diego, California, USA, is a real-time operating system . Similar RTOSes are available from other vendors such as VxWorks, Nucleus RTOS, OSE, QNX, LynxOS, etc...

, Windows CE

Windows CE

Microsoft Windows CE is an operating system developed by Microsoft for embedded systems. Windows CE is a distinct operating system and kernel, rather than a trimmed-down version of desktop Windows...

, Fusion RTOS, Nucleus RTOS

Nucleus RTOS

Nucleus OS is a real-time operating system and toolset created by the Embedded Systems Division of Mentor Graphics for various central processing unit platforms. Nucleus OS is an embedded software solution and is in an estimated 2.11 billion devices worldwide.Development is typically done on a...

, RTEMS

RTEMS

RTEMS is a free open source real-time operating system designed for embedded systems....

, Integrity

Integrity (operating system)

INTEGRITY is a real-time operating system produced and marketed by Green Hills Software. It is royalty-free, POSIX-certified, and intended for use in embedded systems needing reliability, availability, and fault tolerance. It is built atop the velOSity microkernel and is intended mainly for modern...

, QNX

QNX

QNX is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. The product was originally developed by Canadian company, QNX Software Systems, which was later acquired by Canadian BlackBerry-producer Research In Motion.-Description:As a microkernel-based...

 and OSE

Operating System Embedded

The Operating System Embedded is a real-time embedded operating system created by the Swedish information technology company ENEA AB. Bengt Eliasson, who at the time was a consultant from ENEA with an assignment at Ericsson, wrote the basic parts of the kernel...

.

Communications protocols designed for use in embedded systems are available as closed source from companies including InterNiche Technologies

NicheStack TCP/IPv4

NicheStack is a closed source IPv4 network layer and application implementation for operating systems, written in ANSI "C" and is one of four available from InterNiche Technologies, Inc., designed for use in embedded systems. Its Transport Layer implementation has historical roots in BSD and the IP...

 and CMX Systems

CMX Systems

CMX Editing Systems was a company founded jointly by CBS and Memorex, that developed some of the very first computerized systems for linear and non-linear editing of videotape for post production...

, and are also published as open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 from uIP

UIP (micro IP)

The uIP is an open source TCP/IP stack capable of being used with tiny 8- and 16-bit microcontrollers. It was initially developed by Adam Dunkels of the "Networked Embedded Systems" group at the Swedish Institute of Computer Science, licensed under a BSD style license, and further developed by a...

, lwip

LwIP

lwIP is a widely used open source TCP/IP stack designed for embedded systems. lwIP was originally developed by Adam Dunkels at the Swedish Institute of Computer Science and is now developed and maintained by a world wide network of developers led by Kieran Mansley.lwIP is used by many...

and others.