The system BIOS is the lowest-level interface between the hardware of your system and
the software that runs on it. It has several significant roles that it plays in the
control of access to hard disks:
- BIOS Interrupt Routines: In order to ensure the interoperability of various
hardware and software products, the BIOS of the system is tailored to the needs of its
hardware, and provides a standard way of letting software addressing the hardware. These
are called BIOS services and are used by
many operating system and application programs. They provide a uniform interface to the
hard disk, so applications don't need to know how to talk to each type of hard disk
individually. (Many newer operating systems today regularly bypass these BIOS services but still may use them for compatibility
purposes.)
- Hard Disk Detection and Configuration: Standard IDE/ATA hard disks are configured
in the BIOS using various BIOS settings. Modern
BIOSes can in fact interrogate modern IDE/ATA disks to determine these parameters, and
automatically configure them.
- Hard Disk Interface Mode Support: The BIOS, working with the system chipset on
the motherboard and the system I/O bus, controls which types of interface modes can be
used with the hard disk. This refers specifically to features such as high-performance PIO modes, DMA modes,
and block mode.
Next: The Int13h Interface
