Acronyms and Glossary

See also: Member-FAQ

The EFI and Framework Open Source Community lives within a fairly complex world of acronyms, terms, etc. Hopefully this page helps clarify some of those and provides a good reference.

ACPI

Advanced Configuration and Power Interface. See www.acpi.info

AL

Afterlife phase. Also known as the "power down phase."

AML

ACPI Machine Language

API

Application Program Interface. Programmatic interfaces for the firmware (not Win32-type OS-level APIs).

a priori file

A file with a known GUID that contains the list of DXE drivers that are loaded and executed in the listed order before any other DXE drivers are discovered.

Artifact

Something tracked in Project Tracker

ASL

ACPI Source Language

Attribute

A field of something tracked in CEE Project Tracker

BA

Boot Authorization

BBS

BIOS Boot Specification

BDS

Boot Device Selection phase

BFV

Boot Firmware Volume. Code (i.e., PEI and PEIM code) that appears in the memory address space of the system without prior firmware intervention. See also FV.

BIS

Boot Integrity Services

BIST

Built-in self test

BLT

Block Transfer (pronounced "blit" as in "slit" or "flit"). A series of functions that form the basis of manipulation graphical data. The operation used to draw a rectangle of pixels on the screen.

BNF

Backus-Naur Form. A metasyntactic notation used to specify the syntax of programming languages, command sets, and the like

BootDevice

The device handle that corresponds to the device from which the currently executing image was loaded

BootManager

The part of the firmware implementation that is responsible for implementing system boot policy. Although a particular boot manager implementation is not specified in this document, such code is generally expected to be able to enumerate and handle transfers of control to the available OS loaders as well as EFI applications and drivers on a given system. The boot manager would typically be responsible for interacting with the system user, where applicable, to determine what to load during system startup. In cases where user interaction is not indicated, the boot manager would determine what to load and, if multiple items are to be loaded, what the sequencing of such loads would be.

Boot Services

The collection of interfaces and protocols that are present in the boot environment. The services minimally provide an OS loader with access to platform capabilities required to complete OS boot. Services are also available to drivers and applications that need access to platform capability. Boot services are terminated once the OS takes control of the platform.

BSD

Berkeley Software Distribution

BSP

Boot Strap Processor - typically the processor that will execute SEC and PEI

COFF

Common Object File Format. An (originally) Unix *-based file format that is now recognized under several OSs. The format uses one or more header fields followed by the section data for the file

Compatibility16

A traditional legacy BIOS with the POST and BIOS Setup code removed. Compatibility16 BIOS code executes in real mode

CompatibilityBIOS

The combination of both EfiCompatibility and Compatibility16

CompatibilitySmm

Any IBV-provided SMM code to perform traditional functions that are not provided by EFI

CRC

Cyclic Redundancy Check. A fixed-size error checking code appended to the end of a block of data (file) that is based on the content of the file

CRTM

Core Root-of-Trust Module

CSM

Compatibility Support Module. The combination of EfiCompatibility, CompatibilitySmm , and Compatibility16. Portion of the Framework that allows compatibility with non-EFI compliant operating systems to run on Framework firmware

CVDR

Configuration Values Driven through Reset

Depex

Dependency expression. Code associated with each Framework driver that describes the dependencies that must be satisfied in order for that driver to run. Controls order of execution in a Framework dispatch of PEIM and DXE drivers

DispatchEntry Point

The entry point that the dispatcher invokes

Driver

Modular chunk of firmware code that supports chipset or platform features. bReusable in multiple system contexts

DXE

Driver Execution Environment phase

DXE Foundation

A set of intrinsic services and an execution mechanism for sequenced control of driver modules

DXE Services

Services, such as security services and driver services, that are usable by DXE drivers

EfiCompatibility

EFI code that corresponds to EFI compatibility drivers, code that generates data for compatibility interfaces, or code that invokes compatibility services.

EDK

EFI Developer Kit

EPL

Eclipse Public License

Extensible Firmware Interface (EFI)

EFI is a specification that defines the interface between an operating system, option ROMs, and platform firmware. EFI was originally invented by Intel as the Intel(R) Itainum BIOS replacement. EFI is now owned by a industry non-profit collaborative trade organization called The UEFI Forum.

FAT

File Allocation Table

FAT32

FAT32 File System Driver

FD

Firmware Device. A persistent physical repository that contains firmware code and/or data and that may provide NVS. For the purposes of this architecture specification, the topology of bFDs should be abstracted via bFVs.

FFS

Firmware File System. A binary storage format that is well suited to firmware volumes. The abstracted model of the FFS is a flat file system

Firmware Device

See FD.

Firmware Volume

See FV.

FIT

Firmware Interface Tableb.( Itanium systems only)

Font

A translation between Unicode weights and glyphs. This "M" and this "M" and this "M" represent the same weight but in different fonts

FoundationCode

The core interoperability interfaces between modules and in the Framework

FPSWA

Floating Point Software Assist. (Itanium systems only)

Framework

short for Intel® Platform Innovation Framework for EFI

FS

Firmware Store. The abstracted model of the FS is a flat "file system" where individual files are SUMs

FV

There are one or more FVs in the FS. The FV containing the "reset vector" is known as the Boot Firmware Volume (BFV). A FV is a simple Flash File System that starts with a header and contains files that are named by a GUID. The file system is flat and does not support directories. Each file is made up of a series of sections that support encapsulation.

GCD

Global coherency domain. The address resources of a system as seen by a processor. It consists of both system memory and I/O space

glyph

The graphical representation of a single Unicode weight

Globally Unique IDentifier (GUID)

Globally Unique Identifier. A 128-bit value used to differentiate and name services and structures.

HII

Human Interface Infrastructure. Repository of configuration and translation information for localization. Typically used with boot manager and shell to provide a localized user interface.

HOB

Hand-Off Block. A structure used to pass information from one boot phase to another (i.e., from the PEI phase to the DXE phase)

IBV

Independent BIOS Vendor

IFR

Internal Forms Representation. A binary encoding of forms-based display content and configuration information

IHV

Independent Hardware Vendor

IME

Input Method Editor

Intrinsic Services

Services, such as security services and driver services, that remain available after the phase during which they are instantiated

IPL

Initial Program Load. An architectural PEIM to PEIM interface that starts the DXE phase

IPMI

Intelligent Platform Management Interface

ISO 3166

An association between a country or region and a two or three character ASCII string

ISO 639-2

An association between a language or dialect and a three character ASCII string

Localization

Concepts by which an interface is made useful to users speaking different languages and from various cultures by adapting the interfaces to the user. "STOP" in English would be "ALTO" in Spanish and "СТОП" in Russian. Alphabetic on keyboards are local to the language and may be local to the country the keyboard is localized for. For example, a French keyboard in France is different from a French keyboard in Canada.

MCA

Machine Check Architecture

MDE

Module Development Environment

NMI

Non-maskable Iinterrupt

NRAM

Nonvolatile Random Access Memory

NVS

Nonvolatile storage. Flash, EPROM, ROM, or other persistent store that will not go away once system power is removed

ODM

Original Device Manufacturer

OEM

Original Equipment Manufacturer

OpROM

Option ROM

PAL

Processor Abstraction Layer. A binary distributed by Intel that is used by the 64 bit Itanium processor family

PCI

Peripheral Component Interconnect. See www.pcisig.com for more information.

PCR

Platform Configuration Register

PE/COFF

PE32, PE32+, or Common Object File Format. A defined standard file format for binary images

PEI

Pre-EFI Initialization phase. Set of drivers usually designed to initialize memory and the cpu so that DXE phase can run. sually the first bset of code run starting from reset.

PEI Foundation

A set of intrinsic services and an execution mechanism for sequenced control of PEIMs

Pre EFI Initialization Module (PEIM)

Pre-EFI Initialization Module. Modular chunk of firmware code running in PEI that supports chipset or platform features. Reusable in multiple system contexts.

PEI Services

Common services that are usable by PEIMs

PEIM to PEIM Interface (PPI)

A C structure named by a GUID that is published by one PEIM and consumed by another. The C structure can contain data and member functions. It differs from a Protocol in that it may have to function prior to memory being available and parts of the PPI could be in read only memory.

PHIT

Phase Handoff Information Table. A HOB that describes the physical memory used by the PEI phase and the boot mode discovered during the PEI phase.

PIC

Position-independent code. Code that can be executed at any address without relocation

POST

Power On Self Test

Protocol

A C structure named by a GUID that is published by one EFI or DXE driver and consumed by another. The C structure can contain data and member functions.

Reverse Thunk

The code to transition from 16-bit real mode to native execution mode

RSD_PTR

ACPI definition: Root System Description Pointer

RT or Runtime phase

For EFI and the Framework this is after exit boot services has executed and the OS is in control of the system.

Runtime Services

Interfaces that provide access to underlying platform-specific hardware that may be useful during OS runtime, such as time and date services. These services become active during the boot process but also persist after the OS loader terminates boot services.

SAL

System Abstraction Layer. (Itanium systems only)

SALE_ENTRY

System Abstraction Layer entry point. (Itanium systems only)

Sandbox

The common properties of a driver or preboot environment that allow applications to run. These properties include a defined load image format and services that can run in the sandbox.

SEC

SECurity Phase. Initial starting point for boot process, first code executed after hardware reset. Responsible for 1) Establishing root trust in the software space; 2) Initializing architecture specific configuration to establish memory space for the C code stack.

SMI

System Management Interrupt

SMM

System Management Mode

SOR

Schedule on Request

SSE

Streaming SIMD Extensions

SUM

Separately Updateable Module. A portion of the BFV that is treated as a separate module that can be updated without affecting the other SUMs in the BFV.

Tiano

Codename for the Intel Project to develop the Framework

TCB

Trusted Computing Base

TCG

Trusted Computing Group

TE Image

Terse Executable image. An executable image format that is specific to the Framework. This format is used only in PEI and is used for storing executable images in a smaller amount of space than would be required by a full PE32+ image. Is a smaller more compact version of bPE32.

Thunk

The code to transition from native execution mode to 16-bit real mode

UNDI

Universal Network Driver Interface. Silicon specific driver in the preboot LAN stack that interfaces to SNP and PXEBC

Unicode

A standard defining an association between numeric values known as "weights" and characters from the majority of the worlds currently used languages. See the Unicode specification for more information.

USB

Universal Serial Bus. See http://www.usb.org for more information

VFR

Visual Forms Representation. A high-level language representation of IFR

VM

Virtual Machine

VTF

Volume Top File. A file in a firmware volume that must be located such that the last byte of the file is also the last byte of the firmware volume

VT-UTF8

A serial protocol definition that extends VT-100 to support Unicode

Watchdog Timer

An alarm timer that may be set to go off. This can be used to regain control in cases where a code path in the boot services environment fails to or is unable to return control by the expected path.

XIP

Execute In Place. PEI code that is executed from its storage location in a firmware volume

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EDK II FAQ Frequently asked questions about EDK II

UEFI/PI FAQ Frequently asked questions about UEFI/PI