INT 13 - ESDI FIXED DISK - TRANSLATE RBA TO ABA AX = 1C0Eh CH = low 8 bits of cylinder number CL = sector number, high two bits of cylinder number in bits 6 and 7 DH = head number DL = drive number ES:BX -> ABA number Return: CF set on error AH = status Note: ABA (absolute block address) format can be found in IBM ESDI Adapter Technical Reference by using its Device Configuration Status Block .