Writing display drivers for previous versions of Windows required you to write a large amount of assembly code covering a variety of display tasks. In Windows 95, the DIB engine supplies most of the code necessary to create a display driver. All your minidriver needs is the hardware-specific code for your display; you simply redirect the non-device specific calls from GDI to the DIB engine. If you cannot use the DIB engine, you must write a full display driver that supplies the new display functions Windows 95 requires.
Similarly, you have far less code to write for display virtualization. Windows 95 supplies the virtual display driver (VDD) which will make hardware-specific calls to a small virtual display minidriver (mini-VDD) that you write.
The VDD now allows 4-plane VGA applications to run in a Window with some standard SVGA display adapters.
The grabber is no longer a component that should be modified, since it handles all interaction between WINOA386.MOD and the VDD, both of which are now Microsoft-supplied components.
Note
If you have written display drivers for previous versions of Windows, you should use the DIB engine and the VDD because your minidrivers will be simpler, smaller, easier to write, and less likely to have bugs.