Determine the Application Model and Install Applications

Terminal Services applications should be installed through Add or Remove Programs, because this component ensures that applications are installed in multiuser mode. If you prefer to install remotely or through the command line, you must use the CHANGE USER command. Use CHANGE USER /INSTALL to set the terminal server to installation mode, perform the installation, and then use the CHANGE USER /EXECUTE command to reset the server to execution mode.

Applications and software products should be installed before allowing users to connect to the server so that you can test their operation properly before users start activating them. In addition, you should take the following guidelines into consideration when deciding which applications should be installed on a terminal server:

• Do not run 16-bit applications, since they can reduce the number of concurrent users by up to 40 percent and require 50 percent more RAM per user. 16-bit applications will also not run in x64 installations of WS08.
• Do not run MS-DOS applications, since they can consume all of the central processing unit (CPU) resources of a server.
• Applications that run constant processes in the background (spell checking in Microsoft Word, for example) consume more resources.
• Applications that use high-quality graphics consume more bandwidth.

Your Terminal Services should be used to run applications that fall into the following categories:

• Applications that require complex installations. Placing these applications on TS servers reduces the number of installation points and thus the risks of having problems with the installation. You can also solve these problems through application virtualization, as discussed earlier.
• Applications that require frequent changes. Placing these applications on TS servers reduces the number of installation points and, therefore, the installation and deployment workload.
• Applications that are prohibitively expensive on a per-user basis so long as their licensing model allows TS sharing.
• Applications for users with low bandwidth access. This is ideal for wireless devices.
• Applications for users in sites where there are no local servers. If the number of users in a site (ten or fewer) does not warrant a local server, you can give these users access to the same service level by allowing them to use applications remotely.

The Terminal Services application operation model is slightly different from the standard WS08 model because of the multiuser environment. You should also check for compatibility scripts for the applications you install. These scripts modify standard installations to make them TS-compatible. They should be run after the application installation. Scripts are found in the %SYSTEMROOT%\APPLICATION COMPATIBILITY SCRIPTS folder.