INT 13 programming interface. Details for each command can be found on
Ralf Brown\'s Interrupt List
INT 13 Supported Functions

INT 13 Unsupported Functions

These function calls return status in AH=01 and CY flag is set, signaling that the routine is unsupported by XT-IDE BIOS.
INT 13 Future Supported Functions

These function calls currently return status in AH=01 and CY flag is set, signaling that the routine is unsupported by XT-IDE BIOS. Support for these functions may or may not be forthcoming, depending on user requirements
Enhanced INT 13 Supported Functions

These function calls are used only by operating systems that have Enhanced INT 13 support, such as FreeDOS, MS-DOS 7 (DOS that comes with MS Windows 95 and higher).
EINT13 calls allow for drives up to over 2TB in size.
Enhanced INT 13 Unsupported Functions

These function calls return status in AH=01 and CY flag is set, signaling that the routine is unsupported by XT-IDE BIOS.