 NT Embedded
is a new version of the Microsoft® Windows
NT® 4.0 operating system specifically
designed to address the needs of dedicated and embedded systems OEMs.
Based on Windows NT 4.0 with Service Pack 5, Windows NT Embedded 4.0 is
complementary to Windows CE. For example, Windows NT Embedded is advantageous
for solutions that are highly interconnected, require full Win32 binary
compatibility, and/or are tightly integrated with Microsoft BackOffice®
family products in line-of-business systems. Windows CE is more advantageous,
for example, in applications where size and cost are critical (refer to
the Technical Overview section for more comparisons).
Windows NT already provides an excellent foundation for building embedded
systems: a high-performance kernel, pre-emptive multitasking, scalable
asynchronous I/O model, rich layered services, and the ubiquitous Win-32
API. However, there are still many needs that must be addressed including
fault resilience, error recovery, target footprint management, solid-state
operation, remote device management/troubleshooting, and a non-standard/non-existent
UI. Windows NT Embedded 4.0 adds these and other capabilities to Windows
NT. It is a superset of Windows NT 4.0 adding new features and target
design tools that make it suitable to a wider range of embedded applications.
FEATURES & BENEFITS
Scalable Functionality; Supports Both Workstation and Server Features
— Windows NT Embedded can be scaled from a workstation with no
GUI to a full-server, based on the requirements of the application.
There are four licensing configurations: Headless Workstation, Full
Workstation, Headless Server, Full Server.
Authoring Tool Set — Windows NT offers a broad spectrum
of functionality with many opportunities for "componentization".
To take advantage of this, Windows NT Embedded includes an authoring
tool set that is currently composed of two tools, the Target Designer
and the Component Designer. The Target Designer is the primary authoring
tool, allowing you to define the target configuration of the OS and
build the run-time environment for the device. While the Target Designer
defines the set of files and configuration information to be included
on the target system, the Component Designer allows you to define elements
of the OS into components. One or more components comprise a capability
and capabilities are grouped together to form overall system configurations.
It is the inclusion or exclusion of components that ultimately determines
the feature-set of the embedded target. Using the familiar Windows NT
user interface, the tool set guides you through the process of profiling,
defining, and generating customized software system.
Headless support — This enables Windows NT to be used in
devices that boot and run without a mouse, keyboard or display device.
Many embedded systems do not expose either a traditional user interface
(e.g. Windows-based or DOS-based PC) or, in many instances, any local
user interface whatsoever. Windows NT requires a display driver to interface
between the graphics sub-system and the video hardware. All currently
available video display drivers assume and rely on the existence of
underlying video hardware. Windows NT Embedded does not require this.
Read-Only Boot Support — Many embedded devices utilize
ROM to support stateless operation, lower the unit cost and improve
reliability. Windows NT Embedded supports a variety of read-only media
for boot-strapping itself in a manner that is transparent to the applications
and system binaries that access the media.
Solid-State Media Support — Due to environmental factors
such as shock or vibration, many embedded devices use bootable non-volatile
storage media with no moving parts to increase mean time between failure
(MTBF) ratings and to improve overall device robustness. NT Embedded
supports solid state disks and flash memory.
Remote Management — In an embedded system, access to the
operating system and/or application is often through a remote system
of some type, since a user interface on the device itself does not exist
or is not practical to access. Windows NT Embedded provides both character-mode
and graphical management solutions using serial, dial-up, and network
connections.
Error Recovery — Robustness and fault-resilience have always
been design criteria of Windows NT. For example, Windows NT possesses
characteristics such as protected virtual memory and object-based security.
Many embedded applications have more extensive error recovery requirements
since they are often used in 7/24 applications in which operator intervention
and assistance is not practical. Windows NT Embedded solves the issues
associated with "blue screens", the communication of error
conditions normally displayed on the console that require user interaction.
These errors can not only be logged, but can be used to trigger application
software events.
TECHNICAL OVERVIEW
A developer configures a device-specific NTE image by using Target
Designer to select the Windows NT binaries needed by the application,
the binaries associated with the special NTE features required by the
application, and the application itself. In some cases, Component Designer
is needed to recreate reusable components not found in NTE (e.g. device
drivers). Once created, new components are imported into Target Designer,
dependencies are checked, and an OS image is built that can be downloaded
onto the device.
Windows NT Embedded does not compete with Windows CE but rather provides
a complementary choice for embedded developers. There are a number of
design considerations that will help to select the best version of Windows
for your device:
Windows NT Embedded is currently only available for Intel Pentium
and compatible microprocessors. Windows CE supports X86 microprocessors
as well as RISC processors such as MIPS, ARM and StrongARM, SHx, and
PPC.
- Footprint
If a device needs a small footprint, Windows CE is the best choice,
requiring as little as 4MB of RAM. Windows NT Embedded requires
a device with the specfications listed below:
Class 1 — Headless Workstation
Standard Install
Memory: 32 to 256 MB of RAM
Storage (min.): 128 MB
(Build size is about 92 MB.)
Specialized Install
Memory: 16 to 256 MB of RAM
Storage (min.): 32 MB
(Build size is about 32 MB.)
Class 2 — Standard Workstation
Standard Install
Memory: 32 to 256 MB
Storage (min.): 128 MB
(Build size is about 90 MB.)
Specialized Install
Memory: 16 to 256 MB
Storage (min.): 32 MB
(Build size is about 30 MB.)
Windows NT Embedded supports up to 256 MB of RAM Maximum.
- Feature Set
Windows CE is the best choice if the device requires semi-real-time
capabilities, instant on, and the ability to operate in a disconnected
state. Windows NT Embedded would be the better choice if the device
requires the full Win32 API, built-in networking, Windows NT security,
remote administration and management, POSIX support, and extensive
device driver support. Real-time capabilities for NT and NT Embedded
can be added using third party solutions. There is no USB support
for Windows NT Embedded, all drivers for USB support must be custom
written.
Note: NTE Licenses sold only with hard drive or flash drive
media.
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