Embedded OS

An embedded operating system is an operating system for embedded computer systems. Due to the very nature of embedded systems, the operating system has different constraints compared to conventional desktop OS (windows, linux, mac os etc). The embedded processor is often restricted in computational power, along with small memory footprint. Often in mobile based devices, power consumption is a major criteria. The following details of this hub covers some details of the modern embedded OS, with a link and devices it has been ported to.

eCos

Link: http://ecos.sourceware.org/

Summary: eCos (embedded Configurable operating system) is an open source, royalty-free, real-time operating system intended for embedded systems and applications. The highly configurable nature of eCos allows the operating system to be customised to precise application requirements, thus able to deliver the best possible run-time performance and an optimised hardware resource footprint.

Port&Dev: eCos runs on a wide variety of hardware platforms, including ARM, CalmRISC, FR-V, Hitachi H8, IA-32, Motorola 68000, Matsushita AM3x, MIPS, NEC V8xx, PowerPC, SPARC, SuperH and Nios II.

MontaVista Linux

Link: http://www.mvista.com/

Summary: The work on real-time performance has since continued to a point where MontaVista claims to support hard real-time tasks on Embedded Linux as of MontaVista Linux 4.0. The Linux distribution is available in three editions: Professional Edition, Carrier Grade Edition and Consumer Electronics Edition.

Port&Dev: Mobile phones using MontaVista Linux, Motorola A760, Motorola A768, Motorola A768i, Motorola A780, Motorola A910, Motorola A1200, Motorola E680, Motorola E680i, Motorola ROKR E2, NEC N900iL, NEC N901iC, Panasonic P901i, Texas Instruments have announced that they will be using MontaVista Linux (professional edition) as the supported operating system for their new System-on-Chip platform DaVinci.

Windows_CE

Link: http://msdn.microsoft.com/embedded/windowsce/default.aspx

Summary: Windows CE (sometimes abbreviated WinCE) is a variation of Microsoft's Windows operating system for minimalistic computers and embedded systems. Windows CE is a distinctly different kernel, rather than a "trimmed down" version of desktop Windows. It is supported on Intel x86 and lookalikes, MIPS, ARM, and Hitachi SuperH processors. Windows CE is optimized for devices that have minimal storage — a Windows CE kernel may run in under a megabyte of memory. Devices are often configured without disk storage, and may be configured as a "closed" system that does not allow for end user extension (for instance, it can be burned into ROM). Windows CE conforms to the definition of a real-time operating system, with a deterministic interrupt latency. Windows CE has evolved into according to Microsoft's documentation a component-based, embedded, real-time operating system. It is no longer only targeted at hand-held computers.

Port&Dev: Microsoft's AutoPC, Handheld PC, Pocket PC, Pocket PC 2002, Pocket PC 2003, Pocket PC 2003 SE, Smartphone 2002, Smartphone 2003, Windows Mobile 5.0, and many industrial devices and embedded systems. Versions of Windows CE even powered select games for the Sega Dreamcast, and Windows CE can partially run on modded Microsoft Xbox game consoles.

Symbian OS

Link: http://www.symbian.com/about/index.html

Summary: Symbian OS is an operating system, designed for mobile devices, with associated libraries, user interface frameworks and reference implementations of common tools, produced by Symbian Ltd. There are a number of smartphone user interface platforms based on Symbian OS. Symbian OS, with its roots in Psion Software's EPOC is structured like many desktop operating systems, with pre-emptive multitasking, multithreading, and memory protection. Symbian OS's major advantage is the fact that it was built for handheld devices, with limited resources, that may be running for months or years. There is a strong emphasis on conserving memory, using Symbian-specific programming idioms such as descriptors and a cleanup stack. Together with other techniques, these keep memory usage low and memory leaks rare. There are similar techniques for conserving disk space (though the disks on Symbian devices are usually flash memory). Furthermore, all Symbian OS programming is event-based, and the CPU is switched off when applications are not directly dealing with an event. This is achieved through a programming idiom called active objects. Correct use of these techniques helps ensure longer battery life.

Port&Dev: Ericsson R380 (2000), Nokia 9210 Communicator smartphone (32-bit 66MHz ARM9-based RISC CPU) (2001), 9300 Communicator (2004), 9500 Communicator (2004). Used for PDAs such as Sony Ericsson P800 (2002), P900 (2003), P910 (2004), P990, W950, M600, Motorola A920, A925, A1000, DoCoMo M1000, BenQ P30, P31, Nokia 6708. Nokia Series 60 (2002) Nokia Series 60 is used in various phones, the first being the Nokia 7650, then the Nokia 3650, followed by the Nokia 3620/3660, Nokia 6600, Nokia 7610, Nokia 6670 and Nokia 3230. The Nokia N-Gage and Nokia N-Gage QD gaming/smartphone combos are also Series 60 platform devices. It was also used on other manufacturers' phones such as the Siemens SX1, Sendo X, Panasonic X700, Panasonic X800, Samsung SGH-D730, SGH-D720 and the Samsung SGH-Z600. Recent, more advanced devices using Series 60 include the Nokia 6620, Nokia 6630, the Nokia 6680 and Nokia 6682, a next generation N series, including the Nokia N70, Nokia N90, and Nokia N91, and the business model E series, including the Nokia E60, Nokia E61, and Nokia E70. For an up to date list, refer to the Symbian Series 60 website. Nokia 7710 (2004) using the Nokia Series 90 interface.

uClinux

Link: http://uclinux.org/

Summary: uClinux stands for MicroControllerLinux and is pronounced as you-see-Linux) is a Linux kernel fork for microcontrollers (µCs, embedded systems) without a memory management unit (MMU)

Port&Dev: uClinux has successfully been ported to the Cisco 2500, 3000, 4000 routers. Cpu ports can b e found here http://uclinux.org/ports/

OSE

Link: http://www.enea.com/

Summary: The Operating System Embedded (mostly known under the acronym OSE) is a real-time embedded operating system created by the Swedish firm ENEA.OSE uses signalling in the form of messages passed to and from processes in the system. Messages are stored in a queue attached to each process.

QNX

Link: http://www.qnx.com/

Summary: QNX (pronounced either Q-N-X or Q-nix) is a commercial POSIX-compliant Unix-like real-time operating system, aimed primarily at the embedded systems market.

Ports&Dev: QNX Neutrino (2001) has been ported to a number of platforms and now runs on practically any modern CPU that is used in the embedded market. The QNX kernel contains only CPU scheduling, interprocess communication, interrupt redirection and timers. Everything else runs as a user process, including a special process known as proc which performs process creation, and memory management by operating in conjunction with the microkernel. This is made possible by two key mechanisms - subroutine-call type interprocess communication, and a boot loader which can load an image containing not only the kernel but any desired collection of user programs and shared libraries.

Ports&Dev: This includes the x86 family, MIPS, PowerPC, SH-4 and the closely related family of ARM, StrongARM and xScale CPUs.

RTEMS

Link: http://www.rtems.com/

Summary: RTEMS (Real-Time Executive for Multiprocessor Systems) is a free open source real-time operating system designed for embedded systems. RTEMS is distributed under a modified GPL licence, allowing linking of RTEMS objects with other files without requiring the entire executable to be covered by the GPL.

Port&Dev:It has been ported to various target processors (ARM, i386, m68k, MIPS, PowerPC, SH, etc).

ThreadX

Link: http://www.rtos.com/

Summary: ThreadX, developed and marketed by Express Logic, Inc. of San Diego, California, USA, is a real-time operating system (RTOS). The name ThreadX is derived from the fact that threads are used as the executable modules and the letter “X” represents switching, i.e., it switches threads. Like most RTOSes, ThreadX uses a multitasking kernel with preemptive scheduling, fast interrupt response, memory management, interthread communication, mutual exclusion, event notification, and thread synchronization features. Major distinguishing characteristics of ThreadX include priority inheritance, preemption-threshold, efficient timer management, picokernel design, event-chaining, fast software timers, and compact footprint. ThreadX is distributed using a marketing model where source code is provided and licenses are royalty-free. ThreadX is generally used in real-time embedded systems, and it is especially used in deeply embedded systems. Development of embedded systems using ThreadX is typically done on a host machine running Windows, and using cross-compiling target software to run on various target processor architectures.

Port&Dev: Several ThreadX-aware development tools are available, such as Wind River Workbench, ARM RealView, Green Hills Software MULTI, Metrowerks Code Warrior, IAR C-SPY, Lauderbach TRACE32, and visionCLICK.

The Hewlett-Packard line of inkjet printers, digital cameras, and many of its laser printers use ThreadX. It was used in the recent Mars Reconnaissance Orbiter and the Deep Impact mission. ThreadX is apparently widely used in a variety of consumer electronics, medical devices, data networking applications, and SoC development

VxWorks

Link: http://www.windriver.com/

Summary: VxWorks is a Unix-like real-time operating system made and sold by Wind River Systems of Alameda, California, USA. Like most RTOSes, VxWorks includes a multitasking kernel with pre-emptive scheduling and fast interrupt response, extensive intertask communications and synchronization facilities, and a file system.

Port&Dev: The Mars Exploration Rovers Spirit and Opportunity and the MRO use VxWorks. VxWorks is in use in several other spacecraft as well, for example, the Deep Impact mission. Boeing intends to use the operating system in their new 787 airliner. The Linksys WRT54G wireless router, LiteON DVD recorders, Promina multiplexers , used in the early semi-professional digital cameras (like Kodak DC220..DC290, Minolta Dimage 1500EX and Casio QV-5000SX). 3COM, Alcatel, Avaya, Cisco (Now use IOS instead of VxWorks), NEC, Nortel, Siemens, and ZTE. For instance, Siemens Communication Systems such as EWSD, HiCOM, and HiPath use VxWorks as their Interface Cards' OS. Cable modems also use VxWorks such as the Motorola Surfboard range PostScript-based computer printers including the Tektronix Phaser series (now produced by Xerox), ReplayTV on its digital video recorder, Siemens Medical Solutions to control the real time events of its MRI scanners.

Nucleus RTOS

Link: http://www.mentor.com/products/embedded_software/nucleus_rtos/index.cfm/

Summary: Nucleus RTOS is a real-time operating system (RTOS) and full featured toolset created by Accelerated Technology, the Embedded Systems Division of Mentor Graphics for various CPU platforms. Nucleus RTOS is part of a complete embedded solution, which includes: Eclipse-based development tools, UML modeling tools, hardware simulation (embedded prototyping), and middleware. The Nucleus RTOS is specially built for any embedded application including consumer electronics, set-top boxes, cellular phones, and other portable and handheld devices. The scalability allows the Nucleus RTOS to scale down to as small as 13 KB, for both code and data.

Port&Dev: The Nucleus RTOS has been used by Garmin International to develop the CNX80 navigational global positioning system (GPS) for general aviation. It is also used in a large number of Motorola and NEC mobile phones.Nucleus RTOS used by Honeywell for Critical Terrain Awareness Technology in the Aviation Industry. IVL Technologies' On-Key Karaoke Handheld Player Sings along with the Nucleus PLUS Kernel. Logitech uses Nucleus RTOS in its Pocket Video Portable Digital Video Cameras. Nucleus RTOS Selected By SK Telecom To Introduce the World's First Commercialization of CDMA Technology To Korea. Nucleus used in NEC 535M High Definition Mobile Handset. ASC's RBOX Multi-Service Aggregator Family uses Nucleus PLUS. Telephonics using Nucleus in SDI System for USAF C-130 Avionics Modernization Program and Aviation Communication System for 767 Tanker Program.

FreeRTOS

Link: http://www.freertos.org/

Summary: FreeRTOS.orgTM is a portable, open source, mini Real Time Kernel - a free to download and royalty free RTOS that can be used in commercial applications.

Port&Dev: ARM Cortex-M3, ARM7, ARM9, HCS12, MSP430, other 32bit processors, other 16bit processors, AVR processors, PIC processors, other 8bit processors

Prex

Link: http://prex.sourceforge.net/

Summary: The Prex project is an open source initiative to provide a portable real-time operating system for embedded systems. This project originally started to make a royalty-free OS for mobile phones and PDA in order to spread open source movement to such proprietary OS fields. And now, the project target has been shifted to the wider area of real-time and embedded systems.

Windows XP Embedded

Link: http://msdn.microsoft.com/embedded/usewinemb/xp/

Summary: Windows XP Embedded, or XPe, is the componentized version of Microsoft Windows XP Professional. XPe is not related to Windows CE. They target different devices and they each have their pros and cons which make them attractive to different OEMs for different types of devices. For instance, XPe will never get down to the small footprint that CE works in. However, CE doesn't have the Win32 APIs XPe has (although CE has an API that is similar to the Win32 API), nor can it run the tens of thousands of drivers and applications that already exist.

Port&Dev: The devices targeted for XPe have included ATMs, slot machines, cash registers, arcade machines, industrial robotics, thin clients, set-top boxes, network attached storage (NAS), time clocks, etc. Custom versions of the OS can be deployed onto anything but a full-fledged PC;