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Frame buffers in PCI video cards must support the existing Macintosh big-endian pixel ordering. If accessible in more than one data format, frame buffers on cards should also support multiple views (called apertures) by being mapped in different formats to separate areas of memory. These concepts are described in Frame Buffers.
PCI video display cards in Power Macintosh computers should define certain properties in the device tree to let the cards function during system startup. These properties are discussed in PCI Open Firmware Drivers.
PCI video display devices should provide an interrupt to mark vertical blanking intervals. Mac OS utilizes this interrupt to do cursor and screen updates to avoid flicker. If the hardware interrupt for vertical blanking is not provided, a time management task may be installed. For more information on this subject, see Graphics Drivers.
Power Macintosh computers support the ISA bracket for PCI expansion cards.