A report for OEMs and manufacturers who are considering the use of Microsoft Windows NT or XP Embedded in their manufacturing equipment and processes.

The use of Microsoft Windows NT and XP Embedded operating systems offers many attractive benefits while providing rich functionality that can be added to an embedded application. It is important to recognize that to effectively utilize these operating systems, some very important issues must be considered that will affect the way your application runs today and into the future.

Understanding the Use of an Application is Essential to Successful Implementation 

How is the system going to be used today and  in the Future?

Electronic devices with intelligence all use an operating system of some nature.  For this reason there is literally thousands of operating systems.  Many of these are considered embedded because they are highly specific and dedicated to one platform and/or application.  Microsoft Windows NT and XP are commonly used in commercial PCs, medical applications, factory automation, and many other applications around the world.  These feature rich and broadly supported operating systems have become the universal favorite for many applications.  The advantages of using these systems are appealing for many applications.  However, with their comparatively larger size (footprint) and overhead, some applications cannot effectively use these operating systems.

Microsoft offers Embedded versions that can overcome the size and overhead issues.  Chart A (Page 8) describes some of the advantages of using these embedded operating systems in an application.  With the use of these versions a solid understanding of the application and its future uses is essential to the successful implementation of the system.

The benefits and features associated with the Microsoft Embedded operating systems make the choice to investigate the use of this option in an application an easy one.  When considering the use of one of these operating systems there are some hidden issues and concerns that need to be understood.  The remainder of this paper is dedicated to presenting these issues and concerns so that the decision and implementation plans will be successful.  The intent is not to provide a step by step process for implementation but rather to provide a checklist of issues and concerns that can be utilized to make an educated and successful decision.

 "I need Embedded NT on a cost effective solid-state device so that the hard drive can be eliminated," is one of the most frequently requested options heard from Xycom Automation customers.  It becomes very obvious that many times the entire nature of this request is not completely understood.  Windows NT or XP Embedded in its full form can easily be loaded on a system.  To address the second part of this request (elimination of the hard drive), the customer needs to understand what reducing the size of the operating system means both to the application and to the supplier of the system.  This leads to an important question: "How is the system going to be used today and in the future?"  As much as many suppliers wish they could answer this for the customer, the use of the proposed system needs to be determined by the customer and/or the end user.

Understanding the Image Development Process

The first step in deciding to use these operating systems is the understanding of the image development process associated with the implementation of a reduced size image for the system.  To reduce the size of the image, features and/or services need to be eliminated.  Without a clear understanding of which devices and applications are going to be used with the system, a reliable and successful system cannot be developed.  Microsoft supplies a toolkit for customizing the embedded operating system image called Windows Embedded Studio.  Included in the Windows Embedded Studio toolkit are Target Designer, Component Designer, a Component Database and Manager, and Platform-specific tools.  An understanding of the process and each of these tools is crucial to the success of the decision to use one of these embedded operating systems. 

A development process overview, footprint configuration overview, and product datasheets are available at http://www.microsoft.com/windows/embedded/.  The steps in the development process as presented by Microsoft are as follows:

1.      Identify the hardware on your target device.

2.      Choose the features and functionality required in your run-time image.

3.      Identify the embedded system-specific features that need to be included in your target device.

4.      Include custom components.

5.      Build your run-time image.

6.      Deploy your run-time image.

Example issues and concerns associated with each of these steps are discussed individually in the following paragraphs and are not to be construed as instructions.

Hardware – The device supplier, unless supplying the entire system, cannot determine the additional devices that will be added to the system.  Items such as additional I/O device network connections, programmable controllers, vision systems, motion control systems, scanners, data acquisition boards, and many others can only be decided by the OEM and/or end user of the device.  When making a smaller footprint operating system, support for these may not be available if not included in the original image.  For example, Xycom can supply an industrial computer with a solid-state storage device and a reduced size operating system, but if the system has one of the previously mentioned hardware devices added, it might cause the system to function improperly.  For this reason it is important that the OEM and/or the end-user be involved in the development of the original run-time image.

Features and Functionality – Embedded operating systems offer a vast array of features to choose from, unlike full system installations that offer fewer choices of selectable features.  While a normal NT or XP installation allows the user to decide whether or not to install Internet ExplorerÔ, the home page and title bar can be set for the browser using Microsoft Target Designer. The OEM or end-user will be ultimately responsible for what applications will be added after receipt of the base system.  If an application that requires browser support is added and the browser was not included in the run-time image, then the application might not run properly.  This is another example of the importance of the OEM and/or end-user's involvement in the development of the original run-time image.

Embedded System-specific Features – In some cases, the embedded operating system is intended to run on a standard personal computer. However, many times embedded devices have different requirements, including no display capabilities or no writeable hard drive.  The use of smaller solid-state media to store the image is another consideration often included in an embedded application.  With reduced sized media, data may be unable to be stored for extended periods or swap files may be unable to be utilized.   The size of the media and how the system is intended to be used are key in making the correct image.  A failure due to insufficient storage space after implementation will not be an acceptable scenario.  

Custom Components – If the extensive list of available components supplied with these embedded operating systems need to be supplemented, it can be done during the development phase.  These embedded operating systems, unlike a normal desktop system, are intended to be very dedicated to specific tasks and not continually altered after implementation.  Adding components after the image is made may cause the system to improperly function if a feature/service is unavailable.  Third party vendor components, INF files, and other utilities can be directly added to the run-time image before deployment by using Microsoft Target and Component Designers.

Build the Run-time Image – Building the image for these embedded operating systems differs from building an image from source code.  By using Target Designer, the image is generated by reassembling the individual components to create the operating system.  With the use of Windows Embedded Studio, dependencies can be checked and resolved before building the run-time image.  Files and resources can be assembled, directory structures generated, files copied to the appropriate directories, and registry hives can all be accomplished before the image has been finalized.  This process may require multiple attempts if all devices, features, and services needed by the end-user have not been addressed completely.

Deployment of the Run-time Image – The image created on the development system will then need to be transferred to the target platform or device. Once the target device has been deployed, it may be difficult to add software and/or additional hardware without using Windows Embedded Studio. Examples of problems that can be associated with adding devices, software, or services are:

·        No CD-ROM support – How will software be installed?

·        No network services included – How will the unit be connected to the enterprise network in the future?

·        No user interface (display) capability – How will the end-user work with the system?

·        Did not load Internet Explorer – How will software be added that requires it?

Once the run-time image has been determined, many suppliers can provide a target device with the developed run-time image included.

Hardware Selection

Now that the development process is understood, selecting the hardware platform or target device is important.  The requirements for an application will most likely control the type of hardware to be selected.  Once the hardware platform is selected, all auxiliary devices and application software requirements need to be determined.

One consideration in selecting the hardware is the use of a hard drive. Solid-state, or CompactFlashÔ memory devices in some cases, are significantly more reliable than the traditional rotating media hard drive.  Applications that require significant levels of shock and vibration may require the hard drive to be eliminated and replaced with solid-state media.   If a hard drive can be eliminated, then the use of the Microsoft Embedded operating systems may prove to be very beneficial.  The single most important item that will affect the system is the use of swap files.  The standard NT and XP operating systems use swap files that can significantly increase the amount of storage required.  With standard operating systems, the size of the swap files can be reduced but not effectively disabled.  However, with Microsoft Windows NT or XP Embedded, this function can be disabled if desired.  Unlike hard drives, most solid-state media have a limited number of "writes" and "re-writes". The number is usually very large and corresponds to one segment of the media. CompactFlash, for example, has built-in software, which distributes each "write" so that one area is not overburdened.  A good understanding of the application and how it will be used is essential to successful implementation.

The decision to store data on solid-state media for future reference is a major area of concern.  256 MB of CompactFlash storage will be filled more quickly as compared to the capacity of a 20 GB hard drive.  The use of networks to store the data elsewhere, or the use of a hard drive only for storing data, are both options that may be available for the application.  To emphasize the importance of the storage device choice, when a solid-state media (hard drive) fills up, the system and application may terminate unexpectedly.  This is an unacceptable situation in today's manufacturing environment.

Procurement of the hardware is another concern.  Asking a hardware supplier for a system with Windows NT or XP Embedded on CompactFlash is not enough information for the embedded system.  For instance, Xycom could create images and ship product, but if additional hardware and/or software are added that is not fully supported by the image, then the hardware may not function properly.  On the other hand, Xycom could pre-install a customer-supplied image on the hardware platform of choice. Often times, there are several layers of suppliers, distributors, and/or manufacturers that may not entirely understand the application, decreasing the probability of successful implementation.  When the end-user plays an active role in determining the run-time image, the probability of successful implementation of hardware and software is significantly greater.

Application Software Selection

There is a multitude of applications to select from supported by Microsoft Windows NT and XP.  This is one of the major advantages to considering Microsoft Windows NT or XP Embedded.  Selecting the one(s) for the application is important.  Once all have been selected, it is mandatory to investigate and analyze the image to assure that all functions of the package(s) selected are supported.  Microsoft supplies tools in the Windows Embedded Studio toolkit to aid in this process.

It is recommended to include your application in the image so that every unit is set up exactly the same.  This is another example of how important the OEM and/or end-user is in the image generation process.  Hardware suppliers can pre-install the image as supplied by the customer, but asking the hardware supplier to load an Embedded operating system without pre-determining this information may result in a less satisfactory solution for both parties.

Component Selection

With the hardware platform and the application software selected any additional items need to be determined.  These include serial devices, expansion cards, separate controllers, external devices, and additional software that may be required.  These all need to be supported by the generated image.  The Windows Embedded Studio toolkit needs to be utilized to check for dependencies and support.

Any software, drivers, or files that are needed for support should be included in the image.  These support files can be pre-loaded, but without knowledge of any additional items, the image may prove to be unsuccessful.  A good example is when the creation of an original run-time image did not include parallel port services because a printer was not required. Later on, when a software application is added that requires a parallel port hardware key, the added software will not work.

The Future

Now that the current application has been determined, the question, "How will this device be used in the future?" needs to be answered.  Although the system may run the current application successfully, it may not run correctly when different components or software are added in the future. Understanding and including all devices and software for the application is important, so too are future additions to the application.  Many Windows NT or XP Embedded devices will be deployed as dedicated computers.  But in the future, these devices may be perceived as typical computers that allow software and other devices to be added relatively easily.  These new devices or software will need to be re-evaluated using the Windows Embedded Studio toolkit and a new run-time image downloaded to the platform.

Summary

Microsoft Windows NT or XP Embedded operating systems are very appealing choices for many applications.  With their many features and benefits, time to market can be significantly reduced over the development and introduction of a proprietary operating system.  The use of these Embedded operating systems requires more understanding of the application than the implementation of a more traditional commercial operating system. 

Many concerns and issues have been discussed throughout this paper and are summarized in Chart B (Page 9).  It is hoped that this chart can be utilized as an aid in a decision to implement an embedded operating system into an application successfully.  If all issues and concerns are thoroughly considered and the Microsoft Windows Embedded Studio toolkit utilized, then the probability of successful implementation will be greatly increased. 

Before deciding to use these Embedded operating systems, the issues and concerns presented here, as well as a complete understanding of the Microsoft Windows Embedded Studio toolkit and development process should be addressed.  Additional information is available about the embedded operating systems on the Microsoft web site at http://www.microsoft.com/windows/embedded/.  Guide to Developing with Embedded Windows and several other resources are available at http://www.bsquare.com.

Xycom Automation welcomes customers to work closely with us for integrated hardware with preloaded Windows NT or XP Embedded run-time images. Our combined efforts will pay off with successful implementation for today and tomorrow. 

Chart A: Features & Benefits of NT and XP Embedded

Chart B: Issues & Concerns for Successful Implementation

This article is written and provided by Ralph James Damato, Business Unit Manager at Xycom Automation. Xycom Automation is recognized as the market leader in providing industrial computer products designed specifically to operate with maximum reliability in a wide variety of manufacturing and process control environments. For more information about Xycom, please visit their website at www.xycom.com.