To help device manufacturers capitalize on the advantages of Java technology, Sun fosters strategic relationships with authorized Java platform resellers. These resellers focus on delivering Java technology implementations and solutions designed specifically for the embedded device market. This article highlights the advantages of using Java technology in embedded devices, and discusses how the Sun Java platform resellers add value with optimized and compatible implementations.

This is the slide presentation given by John Lombardo (author of Embedded Linux, published by New Riders) at the Embedded Linux Expo & Conference (ELEC) held in Reston, VA during November, 2001. Quoting from the introduction . . .
"Once you have decided to use Linux in your embedded application, now you need to choose how to assemble your kernel and applications suite together into a bootable image. Two years ago, the choice was easy -- roll your own. Now there is a vast array of embedded Linux toolkits from companies like Red Hat, Lineo, and MontaVista. There are also several Open Source projects like PeeWee Linux and Midori. The question is -- how do you choose the right toolkit? Find out about the current state-of-the-art in Embedded Linux toolkits and how to choose among them."

Microsoft has published an online document entitled Why Microsoft Windows XP Embedded and Not Embedded Linux?, in which embedded XP is compared to Embedded Linux in eight ways. Quoting from the introduction . . .
Selecting an operating system (OS) platform is one of the first decisions an embedded developer must make for any given device design. Whether you are considering migrating from a proprietary to commercial platform, or from one commercial platform to another, the objectives are the same: accelerated time to market; a solid, extensible OS core that can be used across all projects; superior technologies that support differentiation and address emerging opportunities; and predictability over the device lifecycle. In addition, you want it at the lowest possible total cost from a reputable vendor who will support you throughout the process.
The document then proceeds to compare XP Embedded to Embedded Linux according to these eight topics, claiming that XP is superior in each case . . .

• Integrated
• Comprehensive
• Unmatched
• Interoperable
• Proven
• Global
• Linux Is Not Free
• OEM Licensing

Answering the Microsoft challenge
Given that fact that "Embedded Linux" is not the product of a single dominant vendor, but rather is the result of the collaborative (and competitive) efforts of an entire market consisting of dozens of large and small companies plus thousands of individual developers, LinuxDevices.com hereby invites the Embedded Linux Community to respond to Why Microsoft Windows XP Embedded and Not Embedded Linux? here at LinuxDevices.com.
Subsequent to the initial issuance of this "Call to Action" by LinuxDevices.com on December 10, 2001, the following rebuttals and responses have been published . . .

• LynuxWorks responds to Microsoft attack on Embedded Linux
• Lineo responds to Microsoft attack
• Lineo rebuttal to Microsoft attack on Embedded Linux - Part II

What is QNX ? It's a 32-bit, Unix-like real-time OS. The demo to which Jonathan refers shows that sophisticated, modern, and powerful software can be delivered in a very small package. Specifically, the QNX demo includes:"

• "The QNX OS microkernel (just 45KB). It's highly modular, letting QNX bundle just the services (TCP/IP, modem, graphics, and netcard detection-logic, and drivers) needed for this demo."
• "The Photon windowing system. Powerful enough to support a full-featured HTML 3.2 browser, but way smaller (also 45-KB) than X or comparable services in Windows or Mac OS."
• "The Voyager browser, derived from the Spyglass modular browser. HTML 3.2, frames, JavaScript, and more in just 400 KBs."
• "Oh, and just for fun, QNX tossed in its embedded Web server."

In a bid to boost its profile in the emerging 'e-device' arena, real-time operating system supplier QNX is going open source - sort of. QNX calls its take on open source, 'accessible source'...
Since QNX uses the same APIs as Linux, such as Posix and X Windows, it hopes to encourage developers who have experience with the open source OS to shift over to Neutrino. Then there's competition with other RTOS vendors. QNX reckons it's number two in the market, behind WinRiver, but with 200-odd vendors in the field, even WinRiver's marketshare is just 10-15 per cent of the market.

There are those who say that Linux has a bigger future in embedded systems than on the desktop. So it's good to know that a few entrenched players in the embedded market seem willing to play nice. (1,400 words)

QNX Software Systems (Ottawa, ONTARIO) has unveiled an aggressive strategy to counter the growing presence of Linux in the embedded market. The QNX strategy lies not in working against Linux, but rather in hitching the company's fortunes to the Linux train -- in a manner of speaking.
It's interesting to note that QNX Software Systems was, after all, one of the first and most successful companies to have come up with a 'UNIX-like' RTOS capable of use in mission critical embedded applications. Now, with Linux (not UNIX) rapidly emerging as a highly popular embedded system operating system, the company is scrambling to recast its popular QNX RTOS as 'Linux-like.' The new QNX initiative consists of several key elements....
Does QNX see Linux as a competing OS?
Here's how QNX answers that question, as published in their document entitled "the Linux FAQ" QNX and Linux share a lot of synergy. In fact, by popularizing the POSIX APIs that QNX embraced over 10 years ago, Linux has actually helped QNX gain more acceptance among OEMs and ISVs. So it's in QNX's interest to see the Linux community grow and flourish. Because QNX and Linux are so compatible, code from Linux projects can be used on QNX, and vice versa. As a result, QNX enables Linux developers to bring their expertise and code investment into the embedded space. Likewise, Linux provides QNX developers with an additional market in which to sell their applications and expertise. In short, the QNX and Linux OSes complement each other and strengthen each other's value to the embedded market. It's also important to remember that the embedded market is huge -- and that different embedded developers have dramatically different OS requirements. There's plenty of room for both QNX and Linux, with their different advantages and approaches to IP ownership.

Selecting an operating system platform is one of the first decisions an embedded developer must make for any given device design. Whether you are considering migrating from a proprietary to commercial platform, or from one commercial platform to another, the objectives are the same: accelerated time to market; a solid, extensible operating system core that can be used across all projects; superior technologies that support differentiation and address emerging opportunities; and predictability over the device lifecycle. In addition, you want it at the lowest possible total cost from a reputable vendor who will support you throughout the process.
For smart, connected, 32-bit devices requiring rich applications, Microsoft® Windows® XP Embedded delivers six distinct advantages over Linux in the embedded space:

• Integrated: An all-inclusive, tool set that delivers faster operating system and application development time
• Comprehensive: An operating system foundation with proven performance and reliability
• Unmatched: A technology portfolio for building the next generation of devices
• Interoperable: Broad interoperability with Microsoft® .NET® enabled applications and services that span devices, PCs, servers and the Web
• Proven: A long-term business model that is better aligned with your business
• Global: A worldwide system to support and speed overall product development

In this article, we review the methods available to serve the needs of applications that involve performance deadlines. We shall see that although precise requirements vary from application to application, there are a number of fundamental issues that are almost always of concern. Since multiple vendors provide differing approaches, it is natural that no one solution will serve all applications best. Through this article, we hope to assist developers in evaluating the value of various alternatives relative to their specific applications.
Our objective is to provide insight into the various choices vendors have made in creating their unique approaches. What good is a preemptible kernel? What advantage is there in having my application running in kernel-space? What disadvantage?

Real-time is a term that characterizes a particular application. Hard real-time means an application fails catastrophically if deadline requirements are not met. Soft real-time means an application suffers degradation in quality, but not catastrophic failure, if deadline requirements are not met. Both hard and soft real-time are terms that are clock time independent. A hard real-time requirement might be relatively slow (i.e., if an event is not serviced within one minute, an engine overheats and breaks down). A soft real-time requirement might be relatively fast (i.e., if a buffer on a networking card is not drained within 200 microseconds of an interrupt event it will overflow, but it will recover from the loss of data). The important point is that soft and hard real-time are attributes of the impact of failure to meet deadlines, and the specific timing requirements are independent of the "hardness" of the requirement...

Embedded system developers find themselves faced with a dilemma: On the one hand, today's highly sophisticated and empowered intelligent embedded systems -- based on the newest chips and hardware capabilities -- demand nothing less than the power, sophistication, and currency of support provided by a popular high-end operating system like Windows.
On the other hand, embedded systems demand extremely high reliability (for non-stop, unattended operation) plus the ability to customize the OS to match an application's unique requirements.
Here's the quandary: general purpose desktop OSes (like Windows) aren't well suited to the unique needs of appliance-like embedded systems. However, commercial RTOSes, while designed to satisfy the reliability and configuration flexibility requirements of embedded applications, are increasingly less desirable due to their lack of standardization and their inability to keep pace with the rapid evolution of technology.

A typical real-time application involves a task performing some operation within a deadline. For example: storing some data, or updating a display. The task often is designed to repeat such activities ad infinitum, beginning each iteration at the occurrence of a hardware interrupt. This interrupt may be caused by a human clicking a button, a temperature reading, data from a visual sensor, or innumerable other possibilities.

Recent years have seen a broadening array of operating system (OS) software options for embedded and real-time system applications. Today, most non-desktop "embedded" systems are based on one of the following alternatives:

• Microsoft Windows : in its three "flavors": Win98, WinNT, WinCE
• wide variety of proprietary real-time OSes (RTOSes) : VxWorks, Lynx, QNX, pSOS, OS9, VRTX, SMX, ...
• "Just plain DOS" : Microsoft MS-DOS, Datalight ROM-DOS, Caldera DR DOS
• UNIX, in many forms : SCO, BSD, Solaris, . . .
• "Home grown" : OSes and RTOSes

...
The result: there are now effectively just three principal OS choices for most embedded or real-time systems (not counting the deeply embedded microcontroller-level apps):

• Windows (98, NT, CE)
• Proprietary RTOSes (QNX, VxWorks, Lynx, ...)
• linux (several major and many minor distributions)

This paper demonstrates the development of a small bibliographic system using Extreme Programming techniques. Part 1 shows development of the model; part 2 shows development of the associated user interface.
Specifically, it shows how unit tests and simple design work together while programming. Observe how the coding process occurs in small steps, just enough implementation to make each test run. There's a rhythm to it, like a pendulum of a clock: test a little, code a little, test a little, code a little. (To bring this out, we'll align test code to the left of the page, and application code to the right.)

Des appareils électroménagers aux gadgets électroniques grand public en passant par les contrôleurs spécialisés utilisés dans l'aviation, les usines et l'automobile, les applications embarquées sont présentes dans de très nombreux domaines. Selon une étude publiée récemment par Evans Data auprès d'environ 500 développeurs, cette galaxie de produits est sur le point d'effectuer un revirement profond en faveur des systèmes d'exploitation non-propriétaires... au premier rang desquels figure linux.

Dans la famille des OS alternatifs, il y a aussi BeOS et QNX. BeOS survivant de la Be Box et QNX étant très implanté dans le secteur de l'embarqué. ArsTechnica a eu l'idée de les comparer.