This overview describes the interface between a Fibre Channel Protocol for SCSI (FCP) and iSCSI device driver and an FCP and iSCSI adapter device driver. The term FC SCSI is also used to refer to FCP devices. It is directed toward those wishing to design and write a FCP device driver that interfaces with an existing FCP adapter device driver. It is also meant for those wishing to design and write a FCP adapter device driver that interfaces with existing FCP device drivers.