Memory Hardware Considerations for a Thin Client (Windows Embedded CE 6.0)

1/5/2010

ROM and RAM requirements for Windows Embedded CE powered thin clients depend on several significant factors, such as CPU selection, implemented applications, and performance considerations.

ROM or Flash

For a run-time image that includes the Windows Thin Client Shell, a minimum of 16 MB of ROM is required. We recommend 32 MB of ROM. Notice that this does not provide for additional software.

For a run-time image that includes the Standard Shell, a minimum of 32 MB of ROM is required. We recommend 64 MB of ROM. Notice that that the 32 MB minimum does not provide for additional software.

Note

By default, the Windows Thin Client design template includes the Windows Thin Client Shell. Also by default, the Enterprise Terminal design template includes the Standard Shell.

Both design templates include .NET Compact Framework 2.0. This adds more than 4 MB to your run-time image size. For more information, see Windows Thin Client Design Template and Enterprise Terminal Design Template.

Generally, flash memory is used for ROM. This lets you upgrade thin client software without having to replace the hardware.

Additionally, the ROM must be sufficient to support software that you add to the thin client run-time image. We recommend that you provide sufficient nonvolatile memory to store a minimal image backup as well as to provide space for the registry to grow to at least 50 kilobytes (KB).

Nonvolatile Memory

A thin client requires sufficient nonvolatile memory, such as flash memory or nonvolatile RAM, to store the universally unique identifier (UUID) and the registry entries that contain the thin client operating system (OS) design settings. Thin clients require 32 MB of ROM, plus user storage.

The UUID requires 128 bytes of memory.

How much nonvolatile memory that is required to store the OS design settings depends on the device, the software that is installed, and the number of connections that are defined on the thin client. A typical thin client device that includes the Remote Desktop Protocol (RDP) client, and that has five defined connections, requires approximately 20 KB of nonvolatile storage.

We also recommend that you provide sufficient nonvolatile memory for the registry to grow to at least 50 KB.

RAM

The thin client system software and the RDP client require at least 64 MB of RAM. This requirement does not include the RAM that is required for the video frame buffer or for the OEM-supplied software. This memory requirement supports a thin client that is running one or two RDP sessions. We recommend 128 MB of RAM or more.

Note

Each RDP session requires approximately 4.5 MB of RAM.

You can change the memory each RDP session uses by adjusting the value of BitmapCacheSize in the registry. For more information, see RDP Registry Settings.

SDRAM

For execution of software on a thin client display screen, your hardware must have 32-bit wide SDRAM with a minimum frequency of 100 megahertz (MHz). To enable a better user experience with smoother graphics output, use more SDRAM to buffer more graphics data. Additionally, more SDRAM enables more applications to reside on the device.

RAM and RDP Sessions

If multiple RDP sessions are required, RAM becomes increasingly important to the operation of a thin client. If a user tries to start a session and there is insufficient RAM, the Windows Thin Client Shell sends a message that the client process cannot be started. In designing your thin client device, consider the needs of your customers when you establish RAM size for your thin client.

See Also

Concepts

Performance Considerations for the Hardware Components of a Thin Client