The Windows NT 3.51 and 4.0 graphics architectures are shown in Figures 1 and 2, respectively. Figure 2 shows the redesign of GDI as a kernel-mode component.
Although there are many different ways to print, the printing path in Figure 2 shows the most common way. The print driver sends data to the spooler via the Graphics Engine, and then the spooler sends data to the parallel/serial driver. Note that the spooler still runs in user mode as a separate process.
Figure 1 Windows NT 3.51 Graphics System Architecture
Figure 2 Windows NT 4.0 Graphics System Architecture