AH = 15h DL = drive number (0=A:, 1=2nd floppy, 80h=drive 0, 81h=drive 1) on return: AH = 00 drive not present = 01 diskette, no change detection present = 02 diskette, change detection present = 03 fixed disk present CX:DX = number of fixed disk sectors; if 3 is returned in AH CF = 0 if successful = 1 if error - XT's must have a BIOS date 1/10/86 or newer - used to determine if INT 13,16 can detect disk change - see INT 13,STATUS