Bitfields for AMD Am53C974A Host Configuration Register:
Bit(s)	Description	)
 15-9	reserved
 8	SCSI bus has been reset
 7	starting BIOS number (bits 6-4) is valid
 6-4	starting BIOS number (000 = BIOS drive 80h, 001 = drive 81h, etc)
 3	this device is a SCSI host
 2	protected-mode driver initialized
 1	real-mode driver initialized
 0	target device present
	=0 indicates that this is a host if bit 3 is set
SeeAlso: #00925,#00926