MEM 0040h:008Eh - FIXED DISK - INTERRUPT CONTROL [not XTIBM PC XT]
Size:	BYTE
Note:	cleared to 00h at start of disk operation, set to FFh by IRQ14
	  handler when hard disk controller completes command
SeeAlso: MEM 0040h:008Ch,MEM 0040h:008Dh,MEM 0040h:008Fh