Windows NT Embedded Under the Hood
By Michael Foley
iApplianceWeb
(06/07/01, 07:21:52 PM EDT)
It used to be that using Windows NT in an information appliance was
like fitting a square peg into a round hole. Windows NT has been
somewhat of a leviathan with bloated code rigidly structured for
desktop PCs and servers that have standardized hardware platforms.
On the other hand, information appliances have varied requirements,
so the operating systems (OSs) they use must be flexible enough to be
customized to different hardware platforms and multiple specifications.
Now Microsoft has tailored NT so that it can fit into a range of
iAppliances that require high performance Web services and have the
necessary hardware resources to handle NT's high overhead. A version
called Windows NT Embedded 4.0 (NT Embedded) was designed to
meet these challenges. NT Embedded specifically addresses the needs
of high-end iAppliances, such as application specific servers, set top
boxes, gateways, and gaming platforms.
Embedded Appliance Platform Group
NT Embedded, along with Windows CE, are the foci of Microsoft's
Embedded and Appliance Platform Group (EAPG). The EAPG's main
purpose is developing operating systems, Web services, multimedia,
and software applications for iAppliance and embedded platforms. Their
strategy revolves around OSs that deliver adaptable, scalable platforms
for network enabled devices. To truly understand NT Embedded, one
must first examine the similarities and differences between Window CE
and NT Embedded.
NT Embedded 4.0 was developed for high-end information appliances
and embedded systems; whereas, Windows CE was targeted for
lower-end devices with limited resources. Together they provide a set
of scalable operating systems and tools based on the WIN32 API for
systems using 32-bit (and higher) processors.
Similarities between Windows NT Embedded and Windows CE include:
Support for x86 processor family
Support for a large variety of hardware and software components
A modular architecture approach
Support for multiple networking protocols
Support for secure communications
Visual Studio Development Environment
Differences between Windows NT Embedded and Windows CE are:
Windows NT Embedded supports all applications for desktop NT
version; Windows CE has support for additional processor families
and offers a high degree of adaptability within the hardware
platform
Windows NT Embedded supports the full Win32 API set; Windows
CE supports a subset of the Win32 API set
Windows NT Embedded has soft real-time support with third party
software; Windows CE has hard real-time support
Windows NT Embedded supports symmetric multiprocessing (SMP)
Windows NT Embedded supports C2-level security
Windows CE has a smaller footprint
Windows CE has lower power requirements for battery-powered
devices
Kicking the Tires
NT Embedded differs from its desktop relative with its modularized
design that uses software components that can be added or removed
depending on the requirements. NT Embedded supports all the
software applications that can be run on the desktop version and will
be so compatible that future embedded versions will be released
approximately 90 days after the desktop version. That means
applications such as Office, IIS, SQL, Windows Media Player, and
DirectX are all offered in NT Embedded. NT Embedded only supports
x86 based processors and requires 12MB of memory and 8 MB of
persistent storage for a minimal build. NT Embedded has no native
real-time support, but third parties, like VenturCom, will provide
extensions for soft real-time support. Embedded features, including
headless support, read-only boot, solid-state media support for
diskless operation, and remote management, are provided for in NT
Embedded.
The next version of NT Embedded will be known as Windows XP
Embedded (XP Embedded). It will have built-in componentization
technology and embedded features like XIP (execute-in-place),
compact PCI, a smaller footprint, a better toolkit, and XML, SOAP, and
UDDI support. XP Embedded will be fully integrated into Microsoft's
.NET strategy for a more network aware OS platform. XP Embedded is
expected to ship in the 4th quarter.
Development Tools
Development tools for NT Embedded include: Visual Studio, Target
Designer, and Component Designer. Visual Studio is the same
development environment used on the desktop version. Software
development can be done with Visual C++, Visual Basic, or Visual
InterDev, using Win32 APIs, MFC, ActiveX controls, COM, and DCOM.
Target Designer tailors the build process for NT Embedded systems and
creates a bootable NT operating system with custom components and
applications for an iAppliance or embedded system. It also has a
graphical development environment that displays a Windows NT
configuration at a component level for developers to customize for their
applications.
Component Designer creates custom components that can be added to
the Target Designer configuration and provides wizards and a graphical
display to create component definition files. These components provide
additional enhancements for NT Embedded. The component definition
file defines the components that are listed in the Target Designer. The
components are imported into the Target Designer so that they can be
added to the NT Embedded build process.
Server Appliance Kit (SAK)
Microsoft has recently released the Server Appliance Kit (SAK) to speed
up development of application specific server appliances such as
caching servers, Web servers, and storage servers. Though the initial
release of the SAK is based on Windows 2000, future versions will be
packaged into NT Embedded's next version, XP Embedded. SAK is a
toolkit designed to help developers and OEMs expedite the building of
server appliances. SAK supports headless operation and can be
managed remotely through Web-based management, SNMP, or Telnet.
It is built for high availability systems and contains reliability features
like watchdog timers, bios fail-over, automatic mirroring, and appliance
monitoring service.
SAK includes:
Hardware Reference Specifications
Device Driver Kit
Software Components for NAS and Web Server Configurations
Software Development Kit
Documentation
Stiff Competition
NT Embedded will see plenty of competition, especially from the Linux
crowd. Linux is somewhat similar in nature to NT Embedded in that it
also was born from the desktop environment, has modular software
components, and possesses comparable support for security,
networking, and Web services. However, Linux's main benefit to most
of its users (other than the fact its not Microsoft) is its open source
model with low cost for development and no licensing fees, though this
is changing for some Linux platforms. Linux, with its large development
community, provides quite a challenge for NT Embedded in the
high-end iAppliance arena.
Bottom Line
Due to the pressure from Linux, Microsoft is slightly modifying the way
it licenses to developers and OEMs. It has created the Windows
Embedded Startup Program (WESP) to encourage new companies to use
Microsoft's embedded platforms. WESP provides access to grants for
free tools and run-time licenses for qualified companies.
For most companies building and selling devices, using Windows NT
Embedded 4.0 requires two separate steps:
A copy of Windows NT Embedded 4.0, which contains Target
Designer, is required to create a customized Windows NT
Embedded 4.0 image.
A runtime operating system license is required to sell devices that
use the customized Windows NT Embedded 4.0 image that is
created by Target Designer.
Windows NT Embedded 4.0 with Target Designer and runtime licenses
can be obtained from Microsoft's distributors, who include:
Avnet Applied Computing
Arrow Electronics
Annasoft Systems
BSquare Corp.
VenturCom, Inc.
NT Embedded was Microsoft's initial foray into delivering a more
feature rich OS for iAppliances. It lacked certain features required for
high availability server systems, but it provided Microsoft with a lesson
on what was needed for future versions. It appears XP Embedded will
capitalize on some of this knowledge. The SAK is also a step in the
right direction for providing a more turnkey environment for bringing
iAppliances to market faster. |
