Terminology for graphics driver writers

Cursor support

The NFB interface provides three levels of cursor mouse movement support.

Full software cursor emulation is the default behavior. This is used when the graphics adapter does not provide cursor support. The cursor is rendered with a combination of DrawMonoImage(D3nfb), DrawImage(D3nfb), and ReadImage(D3nfb).
If the adapter has some available off-screen memory and can transparently blit images from off-screen memory to on-screen, then an intermediate level of cursor support can be developed that has slightly better performance than the previous implementation.
If either the graphics chip or the DAC on the graphics adapter have full hardware cursor support, then the NFB driver can take advantage of this.

For certain graphics architectures (fast system bus, limited off-screen memory), the graphics chip has no hardware cursor support and the graphics adapters using this chip could potentially have several different DACs that implement their hardware cursor differently. For these devices, it is wise to always make the full software cursor emulation (mentioned first above) available, for example by setting a flag in the grafinfo(DSP/4dsp) file on SVR5 and SCO OpenServer 5. This will avoid situations where a new graphics adapter comes out that uses chip A, but doesn't have DAC B, so the NFB driver that uses only the hardware cursor defined for DAC B breaks.