Function 0Bh	Write Long				(XT, AT, XT/286, PS/2)
entry   AH      0Bh 
	CH      cylinder (bits 8,9 in high bits of CL) 
	CL      sector number 
	DH      head number 
	DL      drive ID 
	ES:BX   pointer to buffer containing data 
return  CF      set on error 
		AH      status code (see above)    
	AL      number of sectors actually transferred 
note 1) A "long" sector includes a 4 byte EEC (Extended Error Correction) code 
     2) Used for diagnostics only on PS/2 systems