Describes in detail BIOS functions and data structures that are used as an abstraction layer to allow higher-level applications to access mass storage devices in an interface and command-set-independent manner. To comply with this standard, higher-level software shall call the INT functions using the data structures described in this standard; and system firmware shall provide the INT functions and data structures described in this standard. This standard assumes that the reader is familiar with the conventional INT 13h interface, the usage of the BIOS Device Parameter Table, and the basic operation of mass storage devices.