The mpbios driver extracts configuration information
from the BIOS on multiprocessor systems that conform to the Intel
MultiProcessor Specification. This information is used to attach application
processors and APICs, and to assign interrupts to ISA, EISA and PCI devices.
On modern systems this information is provided by ACPI through the
acpimadt(4) device. On such a system
mpbios will not attach, even if the BIOS also
contains the data structures specified by the Intel MP Specification.
The mpbios driver supports version 1.1 and
1.4 of the Intel MP Specification.
The mpbios driver first appeared in
OpenBSD 4.5, based on code present since
OpenBSD 3.6.