1.2 Features of the Specification
The MP specification includes the following features:
A multiprocessor extension to the PC/AT platform that runs all existing uniprocessor shrink-
wrapped binaries, as well as MP binaries.
Support for symmetric multiprocessing with one or more processors that are Intel architecture
instruction set compatible, such as the CPUs in the Intel486™ and the Pentium
Support for symmetric I/O interrupt handling with the APIC, a multiprocessor interrupt
Flexibility to use a BIOS with minimal MP-specific support.
An optional MP configuration table to communicate configuration information to an MP
Incorporation of ISA and other industry standard buses, such as EISA, MCA, VL and PCI
buses in MP-compliant systems.
Requirements that make secondary cache and memory bus implementation transparent to
There are many vendors building innovative MP systems based on Intel architectures today. Intel
supports and encourages vendors to develop advanced approaches to the technological
requirements of today's computing environments. In no way does the MP specification prevent
system manufacturers from adding their own unique value to MP systems. This specification does
not define the only way that multiprocessor systems can be implemented. Vendors may, for
example, create noncompliant, high-performance, scalable multiprocessor systems that do not have
the PC/AT compatibility required by this specification. Hardware vendors will always have the
option of offering one or more customized operating systems that support the unique, value-added
capabilities that they have designed into their systems. End users will be able to benefit from the
additional capabilities that these vendors offer.
The MP specification benefits PC vendors who wish to offer MP-enabled systems without having
to invest in the customization of one or more operating systems. This specification focuses on
providing a standard mechanism to add MP support to personal computers built around the PC/AT
hardware standard. With that goal, the specification covers only the minimum set of capabilities
required to extend the PC/AT platform to be MP-capable. The hardware required to implement the
MP specification is kept to a minimum, as follows:
One or more processors that are Intel architecture instruction set compatible, such as the CPUs
in the Intel486 or Pentium processor family.
One or more APICs, such as the Intel 82489DX Advanced Programmable Interrupt Controller
or the integrated
together with a discrete I/O APIC
The necessary supporting electronics to duplicate the initialization and signaling protocol
described in this specification.
APIC, such as that
on the Intel Pentium 735\90 and 815\100