Windows 2000 native printer drivers run in USER mode. However, in the course of installing and managing printer drivers for redirection on your Terminal Server, it may be necessary—and it is possible—to run Windows NT 4.0-style KERNEL-mode printer drivers on your server. This situation highlights an important difference between Windows 2000 drivers and Windows NT 4.0’s architecture for printer drivers. This section explains how this potential error condition can affect your server.
From a user perspective, both KERNEL-mode and USER-mode drivers look and operate the same. Only the symptoms from potential failures differ.
In Windows NT 4.0, fatal errors in the KERNEL mode space are not allowed. When this does happen, it produces what is known as a STOP error, or a blue screen. As a result, the kernel halts all processing, displays debug information on a screen, and perhaps also writes the debug information to a file on disk. Depending on how your server is configured, the kernel either sits at this screen or reboots, which disconnects all clients and causes a loss of productivity.
Windows 2000’s driver architecture was changed to make printer driver code run in USER mode, where a fatal error results in the loss of the Spooler process space only. A failure in a Windows 2000 printer driver means that only printing functionality is lost. The server remains running without losing client data, other than the data that was being processed through the Spooler.
Most OEM-supplied drivers that caused blue-screen errors in Windows NT 4.0 have been fixed, and the updated versions are available on the vendors’ Web sites.
As a best practice, if you choose to use KERNEL-mode printer drivers, you should make every effort to obtain the latest versions from the manufacturer wherever possible.
You can distinguish Windows NT 4.0 style KERNEL-mode drivers from USER-mode drivers by checking the UI on the Drivers tab under File, Server Properties in the Printers folder.
On this tab, Windows NT 4.0 drivers are listed with the following version:
“Windows NT 4.0 or Windows 2000”
Native Windows 2000 USER-mode drivers are displayed with the following version:
“Windows 2000”
You should identify a KERNEL-mode driver vs. a USER-mode driver before you decide whether to run these drivers in your TS implementation or audit existing servers in your TS implementation.
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