Thin Client Architecture (Windows CE 5.0)

Article
09/14/2012

Thin client is a minimal version of Microsoft Windows CE that includes the core operating system (OS) and Catalog items, including Microsoft RDP, necessary to support a Remote Desktop device.

The following table shows the modes in which RDP can run:

Mode	Description
Windows	This is the default mode. In this mode, RDP can run in or outside of GWES. By default, RDP runs in GWES, and the interface to it is through standard Windows messages. When running in GWES, the shell cannot host RDP in a Web browser or in its own process space. This reduces the overhead of a call to a function in another process. Note Alternately, RDP can run outside of GWES. This alternate method is not shown in the following illustrations.
ActiveX	When running in ActiveX control, the shell can host RDP in a Web browser or in a custom container that you create. For example, CETSC.EXE can be the container, or you can modify CETSC to make a custom container.

Windows

This is the default mode. In this mode, RDP can run in or outside of GWES.

By default, RDP runs in GWES, and the interface to it is through standard Windows messages. When running in GWES, the shell cannot host RDP in a Web browser or in its own process space. This reduces the overhead of a call to a function in another process.

Note Alternately, RDP can run outside of GWES. This alternate method is not shown in the following illustrations.

ActiveX

When running in ActiveX control, the shell can host RDP in a Web browser or in a custom container that you create. For example, CETSC.EXE can be the container, or you can modify CETSC to make a custom container.

For more information about the modes of operation, see RDP Modes of Operation in Windows CE.

The following architectural illustrations show these modes respectively.

ms927506.windows_mode_rdp_gwes(en-us,MSDN.10).gif

ms927506.windows_mode_rdp_not_gwes(en-us,MSDN.10).gif

Software

The following list shows the Thin Client Software. For specific software requirements, see Thin Client Software Requirements.

Shell
The Shell provides the basic framework for the user interface on an OS design. The shell works to present a consistent look and feel throughout the computing experience and can be used to locate files and folders. The following table shows the two types of shells.

Shell	Description
Thin Client Shell	The Windows Thin Client Shell is designed specifically for Windows Thin Client, and does not expose an interface for starting arbitrary applications. The Thin Client Shell can run with or without a default connection. The Thin Client runs with a default connection as the default. On device startup, the Thin Client Setup Wizard is bypassed and a default connection launches the Windows CE Terminal Services Client (CETSC). The user is prompted for a server. When running with a default connection, user input is saved in an .rdp file. For more information, see Terminal Services Client Configuration through the .rdp File. When the Thin Client runs without a default connection, on device startup, the Thin Client Setup Wizard is displayed in which to set up a connection. When the Thin Client runs without a default connection, user input is saved in the registry. For more information, see Configuring the Terminal Services Client.
Standard Shell	On device startup, the standard Windows CE Shell is displayed, containing the CETSC icon on the desktop. The user must select the CETSC icon to make a connection. The user input is saved in an .rdp file. For more information, see Terminal Services Client Configuration through the .rdp File.

Thin Client Shell

The Windows Thin Client Shell is designed specifically for Windows Thin Client, and does not expose an interface for starting arbitrary applications.

The Thin Client Shell can run with or without a default connection.

The Thin Client runs with a default connection as the default. On device startup, the Thin Client Setup Wizard is bypassed and a default connection launches the Windows CE Terminal Services Client (CETSC). The user is prompted for a server.

When running with a default connection, user input is saved in an .rdp file. For more information, see Terminal Services Client Configuration through the .rdp File.
When the Thin Client runs without a default connection, on device startup, the Thin Client Setup Wizard is displayed in which to set up a connection.

When the Thin Client runs without a default connection, user input is saved in the registry. For more information, see Configuring the Terminal Services Client.

Standard Shell

On device startup, the standard Windows CE Shell is displayed, containing the CETSC icon on the desktop. The user must select the CETSC icon to make a connection. The user input is saved in an .rdp file. For more information, see Terminal Services Client Configuration through the .rdp File.

Setup Wizard
The Setup wizard is used only in the Thin Client Shell and runs the first time that a Windows Thin Client is turned on.
IE sample
The sample browser application, Internet Explorer (IE), that ships with Platform Builder. For more information, see Creating and Customizing an Internet Browser.
Third party container
A custom container that you or a third party creates.
GWES
Graphics, Windowing, and Events Subsystem (GWES) is the interface between the user, the applications, and the operating system (OS). It consists of the Microsoft Win32® application programming interface (API), user interface (UI), and graphics device interface (GDI) libraries. GWES supports all the resources, controls, and window controls that make up the Windows CE UI, which enables users to control applications. GWES also includes support for user input and for GDI, which includes support for fonts, text drawing, line and shape drawing, palettes, and printing.
CETSC executable
Terminal Services Client (CETSC) derives from Microsoft Terminal Services Client (MSTSC). CETSC is a sample shell that provides a user interface (UI). The CETSC enables a thin client that is not using the Windows Thin Client Shell to access Windows-based applications on the Terminal Server.

When the CETSC shell is used, user preferences are saved in .rdp files. For more information, see Windows CE Terminal Services Client (CETSC).
MSTSCAX
MSTSCAX is a Microsoft® ActiveX® Control that runs in Windows and handles all communications for the RDP client.
ActiveX layer
This allows you to host RDP in a browser window or in your own container. If you have enabled a virtual channels application in your Terminal Services deployment, the application can also be made available to client computers by means of the Remote Desktop ActiveX Control Interface. For more information, see Remote Desktop ActiveX Control Interface.
UI layer
The user interface to the RDP client core and window management software.
Scriptable virtual channels
Virtual channels that can be invoked by Internet Explorer or Visual Basic. For more information, see RDP Functions.
RDP Core
This includes the core technologies required to support the RDP protocol.
File storage redirection and filtered storage redirection
File storage redirection allows you to view and manage folders on your local drives in a remote session. If file storage redirection is enabled, you can use the filtered file storage redirection to specify the directories that are available within the RDP session. File storage redirection works by using an internal virtual channel
Virtual channel
Virtual channels are custom data formats handled independently of the RDP protocol. They let you add new technologies without having to modify the RDP protocol. For more information, see Implementing Virtual Channels.

If you have enabled a virtual channels application in your Terminal Services deployment, the application can also be made available to client computers by means of the Remote Desktop ActiveX Control Interface.

Hardware

The following list shows the Thin Client Hardware. For specific hardware requirements, see Thin Client Hardware Requirements.

RAM, ROM, and nonvolatile memory
RAM, ROM, and nonvolatile memory holds the Thin Client software and provides the space in which to run applications. The amount of each type of memory required depends on the Catalog items included in the Thin Client, the software installed, and the number of Thin Client connections that are defined. In situations in which multiple RDP sessions are required, RAM becomes increasingly critical to the operation of the terminal.
I/O devices
I/O devices include a display device, keyboard, pointing device, such as a mouse or touch screen, audio output hardware (optional), and network connectivity.

Thin Client Architecture (Windows CE 5.0)

Software

Hardware

See Also

Additional resources