interrupt 13 (Int 13)

The software-based interrupt request interrupt 13 (Int 13) serves as the logical interface of the BIOS for controlling the sectors of a hard disk.

The sectors of a track and the cylinders are controlled via interrupt 13, which contains the hard disk addressing. Since the initial address space of Int 13 comprised 24 bits, the address space that can be controlled was limited to 504 megabytes( MB). For this reason, Int 13 Extended increased the addressable address space to 64 bits, which theoretically corresponds to a storage capacity of several billion terabytes( TB).