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The MultiProcessor Specification (MPS) for the x86 architecture is an open standard describing enhancements to both operating systems and firmware, which will allow them to work with x86-compatible processors in a multi-processor configuration. MPS covers Advanced Programmable Interrupt Controller (APIC) architectures.
Version 1.1 of the specification was released on April 11, 1994. Version 1.4 of the specification was released on July 1, 1995, which added extended configuration tables to improve support for multiple PCI bus configurations and improve expandability.
The Linux kernel and FreeBSD are known to support the Intel MPS. Windows NT are known to support MPS 1.1 and, through later Service Packs, also MPS 1.4. Windows 2000 or higher are known to support MPS 1.4. OS/2 are known to support MPS 1.1 only. Mac OS X are known to support MPS 1.4 only.
There is a utility called 'mptable' which can be used to examine the MPS table on motherboards.
Since most newer machines support Advanced Configuration and Power Interface (ACPI) which subsumes the MPS functionality, MPS has for the most part been supplanted by ACPI. MPS can still be useful on machines or with operating systems that do not support ACPI.
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In computing, BIOS is firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process. The BIOS firmware comes pre-installed on an IBM PC or IBM PC compatible's system board and exists in some UEFI-based systems to maintain compatibility with operating systems that do not support UEFI native operation. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS originally proprietary to the IBM PC has been reverse engineered by some companies looking to create compatible systems. The interface of that original system serves as a de facto standard.
IA-32 is the 32-bit version of the x86 instruction set architecture, designed by Intel and first implemented in the 80386 microprocessor in 1985. IA-32 is the first incarnation of x86 that supports 32-bit computing; as a result, the "IA-32" term may be used as a metonym to refer to all x86 versions that support 32-bit computing.
x86 is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introduced in 1978 as a fully 16-bit extension of Intel's 8-bit 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186, 80286, 80386 and 80486 processors. Colloquially, their names were "186", "286", "386" and "486".
In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, address buses, or data buses of that size. A computer that uses such a processor is a 64-bit computer.
x86-64 is a 64-bit version of the x86 instruction set, first announced in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mode.
In computing, Physical Address Extension (PAE), sometimes referred to as Page Address Extension, is a memory management feature for the x86 architecture. PAE was first introduced by Intel in the Pentium Pro, and later by AMD in the Athlon processor. It defines a page table hierarchy of three levels (instead of two), with table entries of 64 bits each instead of 32, allowing these CPUs to directly access a physical address space larger than 4 gigabytes (232 bytes).
Unified Extensible Firmware Interface is a specification that defines the architecture of the platform firmware used for booting the computer hardware and its interface for interaction with the operating system. Examples of firmware that implement the specification are AMI Aptio, Phoenix SecureCore, TianoCore EDK II, InsydeH2O. UEFI replaces the BIOS which was present in the boot ROM of all personal computers that are IBM PC compatible, although it can provide backwards compatibility with the BIOS using CSM booting. Intel developed the original Extensible Firmware Interface (EFI) specification. Some of the EFI's practices and data formats mirror those of Microsoft Windows. In 2005, UEFI deprecated EFI 1.10.
x86 virtualization is the use of hardware-assisted virtualization capabilities on an x86/x86-64 CPU.
QEMU is a free and open-source emulator. It emulates a computer's processor through dynamic binary translation and provides a set of different hardware and device models for the machine, enabling it to run a variety of guest operating systems. It can interoperate with Kernel-based Virtual Machine (KVM) to run virtual machines at near-native speed. QEMU can also do emulation for user-level processes, allowing applications compiled for one architecture to run on another.
UEFI Forum, Inc. is an alliance between technology companies to coordinate the development of the UEFI specifications. The board of directors includes representatives from twelve promoter companies: AMD, American Megatrends, ARM, Apple, Dell, Hewlett Packard Enterprise, HP Inc., Insyde Software, Intel, Lenovo, Microsoft, and Phoenix Technologies.
Advanced Configuration and Power Interface (ACPI) is an open standard that operating systems can use to discover and configure computer hardware components, to perform power management, auto configuration, and status monitoring. First released in December 1996, ACPI aims to replace Advanced Power Management (APM), the MultiProcessor Specification, and the Plug and Play BIOS (PnP) Specification. ACPI brings power management under the control of the operating system, as opposed to the previous BIOS-centric system that relied on platform-specific firmware to determine power management and configuration policies. The specification is central to the Operating System-directed configuration and Power Management (OSPM) system. ACPI defines hardware abstraction interfaces between the device's firmware, the computer hardware components, and the operating systems.
The High Precision Event Timer (HPET) is a hardware timer available in modern x86-compatible personal computers. Compared to older types of timers available in the x86 architecture, HPET allows more efficient processing of highly timing-sensitive applications, such as multimedia playback and OS task switching. It was developed jointly by Intel and Microsoft and has been incorporated in PC chipsets since 2005. Formerly referred to by Intel as a Multimedia Timer, the term HPET was selected to avoid confusion with the software multimedia timers introduced in the MultiMedia Extensions to Windows 3.0.
In a computer, an interrupt request is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Hardware interrupts are used to handle events such as receiving data from a modem or network card, key presses, or mouse movements.
In computing, Intel's Advanced Programmable Interrupt Controller (APIC) is a family of programmable interrupt controllers. As its name suggests, the APIC is more advanced than Intel's 8259 Programmable Interrupt Controller (PIC), particularly enabling the construction of multiprocessor systems. It is one of several architectural designs intended to solve interrupt routing efficiency issues in multiprocessor computer systems.
System Management Mode is an operating mode of x86 central processor units (CPUs) in which all normal execution, including the operating system, is suspended. An alternate software system which usually resides in the computer's firmware, or a hardware-assisted debugger, is then executed with high privileges.
The term Legacy Plug and Play, also shortened to Legacy PnP, describes a series of specifications and Microsoft Windows features geared towards operating system configuration of devices, and some device IDs are assigned by UEFI Forum. The standards were primarily aimed at the IBM PC standard bus, later dubbed Industry Standard Architecture (ISA). Related specifications are also defined for the common external or specialist buses commonly attached via ISA at the time of development, including RS-232 and parallel port devices.
A page, memory page, or virtual page is a fixed-length contiguous block of virtual memory, described by a single entry in a page table. It is the smallest unit of data for memory management in an operating system that uses virtual memory. Similarly, a page frame is the smallest fixed-length contiguous block of physical memory into which memory pages are mapped by the operating system.
Dynamic frequency scaling is a power management technique in computer architecture whereby the frequency of a microprocessor can be automatically adjusted "on the fly" depending on the actual needs, to conserve power and reduce the amount of heat generated by the chip. Dynamic frequency scaling helps preserve battery on mobile devices and decrease cooling cost and noise on quiet computing settings, or can be useful as a security measure for overheated systems.
SeaBIOS is an open-source implementation of an x86 BIOS, serving as a freely available firmware for x86 systems. Aiming for compatibility, it supports standard BIOS features and calling interfaces that are implemented by a typical proprietary x86 BIOS. SeaBIOS can either run on bare hardware as a coreboot payload, or can be used directly in emulators such as QEMU and Bochs.
In computing, the term 3 GB barrier refers to a limitation of some 32-bit operating systems running on x86 microprocessors. It prevents the operating systems from using all of 4 GiB (4 × 10243 bytes) of main memory. The exact barrier varies by motherboard and I/O device configuration, particularly the size of video RAM; it may be in the range of 2.75 GB to 3.5 GB. The barrier is not present with a 64-bit processor and 64-bit operating system, or with certain x86 hardware and an operating system such as Linux or certain versions of Windows Server and macOS that allow use of Physical Address Extension (PAE) mode on x86 to access more than 4 GiB of RAM.