The following changes are relevant to graphics drivers:
GDI and graphics drivers have been moved to kernel mode for improved graphics performance and memory savings. See the Appendix in the Graphics Driver Design Guide for a snapshot of the new architecture and for porting tips. The Appendix also lists new and obsolete functions.
Windows NT now supports language monitors. Vendors with bidirectional devices that use PJL can use the system-supplied pjlmon; other vendors can develop their own language monitors. The port monitor design has been enhanced to support bidirectional port communication. See the Graphics Driver Design Guide for details.
Minimal DirectDraw driver support is available to driver writers who want to offer DirectDraw support in their Windows NT 4.0 display drivers. Reference pages for supported DirectDraw driver functions and structures are found in the Graphics Driver Reference.
Direct3D hardware support will be available in a post-4.0 Windows NT release. Hardware manufacturers targeting the games market should write Direct3D drivers for Windows 95 and keep in touch for news of availability on Windows NT. Those manufacturers targeting the mid- to high-end 3D market should consider using the Mini Client Driver (MCD) model to accelerate OpenGL applications. The MCD interface is appropriate for a wide range of 3D hardware. Manufacturers targeting the high-end market should consider moving to the Installable Client Driver (ICD) model to support OpenGL. For further information on these alternatives send email to ihv@microsoft.com with a subject line including the text “3D Drivers on Windows NT”.
The device driver interface for 3D hardware (3D DDI) is not supported in Windows NT Version 4.0.