computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...

, the Executable and Linkable FormatTool Interface Standard (TIS)
Portable Formats Specification
Version 1.1'' (October 1993) (ELF, formerly named Extensible Linking Format), is a common standard

file format A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary or free. Some file formats ...

for

executable In computing, executable code, an executable file, or an executable program, sometimes simply referred to as an executable or binary, causes a computer "to perform indicated tasks according to encoded instruction (computer science), instructi ...

files,

object code In computing, object code or object module is the product of a compiler. In a general sense object code is a sequence of statements or instructions in a computer language, usually a machine code language (i.e., binary) or an intermediate langua ...

shared libraries In computer science, a library is a collection of non-volatile resources used by computer programs, often for software development. These may include configuration data, documentation, help data, message templates, pre-written code and su ...

, and

core dump In computing, a core dump, memory dump, crash dump, storage dump, system dump, or ABEND dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has crashed or otherwise terminat ...

s. First published in the specification for the

application binary interface In computer software, an application binary interface (ABI) is an interface between two binary program modules. Often, one of these modules is a library or operating system facility, and the other is a program that is being run by a user. An ' ...

(ABI) of the

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

operating system version named System V Release 4 (SVR4), and later in the Tool Interface Standard,Tool Interface Standard (TIS)
Executable and Linking Format (ELF) Specification
Version 1.2'' (May 1995) it was quickly accepted among different vendors of

systems. In 1999, it was chosen as the standard binary file format for Unix and

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

systems on

x86 x86 (also known as 80x86 or the 8086 family) 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 introd ...

processors by the

86open In computing, the Executable and Linkable FormatTool Interface Standard (TIS) Portable Formats SpecificationVersion 1.1'' (October 1993) (ELF, formerly named Extensible Linking Format), is a common standard file format for executable files, obj ...

project. By design, the ELF format is flexible, extensible, and

cross-platform In computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform software r ...

. For instance, it supports different endiannesses and address sizes so it does not exclude any particular

central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

(CPU) or

instruction set architecture In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ' ...

. This has allowed it to be adopted by many different

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

s on many different hardware platforms.

File layout

Each ELF file is made up of one ELF header, followed by file data. The data can include: * Program header table, describing zero or more memory segments * Section header table, describing zero or more sections * Data referred to by entries in the program header table or section header table ELF Executable and Linkable Format diagram by Ange Albertini

ELF Executable and Linkable Format diagram by Ange Albertini

The segments contain information that is needed for

run time Run(s) or RUN may refer to: Places * Run (island), one of the Banda Islands in Indonesia * Run (stream), a stream in the Dutch province of North Brabant People * Run (rapper), Joseph Simmons, now known as "Reverend Run", from the hip-hop group ...

execution of the file, while sections contain important data for linking and relocation. Any

byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...

in the entire file can be owned by one section at most, and orphan bytes can occur which are unowned by any section.

File header

The ELF header defines whether to use

32-bit In computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculation ...

64-bit In computer architecture, 64-bit Integer (computer science), integers, memory addresses, or other Data (computing), data units are those that are 64 bits wide. Also, 64-bit central processing unit, CPUs and arithmetic logic unit, ALUs are those ...

addresses. The header contains three fields that are affected by this setting and offset other fields that follow them. The ELF header is 52 or 64 bytes long for 32-bit and 64-bit binaries respectively.

Program header

The program header table tells the system how to create a process image. It is found at file offset , and consists of entries, each with size . The layout is slightly different in

ELF vs

ELF, because the are in a different structure location for alignment reasons. Each entry is structured as:

Section header

Tools

readelf 
readelf is a program for displaying various information about object files on Unix-like systems such as objdump. It is part of the GNU binutils.
  readelf and objdump 
objdump has a similar function but with different features like  disassembling.  ...

is a Unix binary utility that displays information about one or more ELF files. A

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

implementation is provided by

GNU Binutils The GNU Binary Utilities, or , are a set of programming tools for creating and managing binary programs, object files, libraries, profile data, and assembly source code. Tools They were originally written by programmers at Cygnus Solutions. ...

. * elfutils provides alternative tools to

purely for Linux. * elfdump is a command for viewing ELF information in an ELF file, available under Solaris and

FreeBSD FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...

. *

objdump 

objdump is a command-line program for displaying various information about object files on Unix-like operating systems. For instance, it can be used as a disassembler to view an executable in assembly form. It is part of the  GNU Binutils for fine ...

provides a wide range of information about ELF files and other object formats. objdump uses the

Binary File Descriptor library The Binary File Descriptor library (BFD) is the GNU Project's main mechanism for the portable manipulation of object files in a variety of formats. , it supports approximately 50 file formats for some 25 instruction set architectures. History ...

as a back-end to structure the ELF data. * The Unix

file 

File or filing may refer to:

 Mechanical tools and processes
* File (tool), a tool used to ''remove'' fine amounts of material from a workpiece
**Filing (metalworking), a material removal process in manufacturing
** Nail file, a tool used to gent ...

utility can display some information about ELF files, including the

for which the code in a relocatable, executable, or shared object file is intended, or on which an ELF

was produced.

Applications

Unix-like systems

The ELF format has replaced older executable formats in various environments. It has replaced a.out and

COFF The Common Object File Format (COFF) is a format for executable, object code, and shared library computer files used on Unix systems. It was introduced in Unix System V, replaced the previously used a.out format, and formed the basis for ex ...

formats in

operating systems: *

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

Solaris Solaris may refer to: Arts and entertainment Literature, television and film * ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem ** ''Solaris'' (1968 film), directed by Boris Nirenburg ** ''Solaris'' (1972 film), directed by ...

Illumos Illumos (stylized as illumos) is a partly free and open-source Unix operating system. It is based on OpenSolaris, which was based on System V Release 4 (SVR4) and the Berkeley Software Distribution (BSD). Illumos comprises a kernel, device d ...

IRIX IRIX ( ) is a discontinued operating system developed by Silicon Graphics (SGI) to run on the company's proprietary MIPS workstations and servers. It is based on UNIX System V with BSD extensions. In IRIX, SGI originated the XFS file system and ...

NetBSD NetBSD is a free and open-source Unix operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was forked. It continues to be actively developed and is a ...

OpenBSD OpenBSD is a security-focused, free and open-source, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by forking NetBSD 1.0. According to the website, the OpenBSD project em ...

Redox Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...

DragonFly BSD DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD in Ju ...

Syllable A syllable is a unit of organization for a sequence of speech sounds typically made up of a syllable nucleus (most often a vowel) with optional initial and final margins (typically, consonants). Syllables are often considered the phonological "bu ...

HP-UX HP-UX (from "Hewlett Packard Unix") is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on Unix System V (initially System III) and first released in 1984. Current versions support HPE Integrity Ser ...

(except for 32-bit PA-RISC programs which continue to use SOM) *

QNX QNX ( or ) is a commercial Unix-like real-time operating system, aimed primarily at the embedded systems market. QNX was one of the first commercially successful microkernel operating systems. The product was originally developed in the early ...

Neutrino * MINIX

Non-Unix adoption

ELF has also seen some adoption in non-Unix operating systems, such as: *

OpenVMS OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Ope ...

, in its

Itanium Itanium ( ) is a discontinued family of 64-bit Intel microprocessors that implement the Intel Itanium architecture (formerly called IA-64). Launched in June 2001, Intel marketed the processors for enterprise servers and high-performance comput ...

and

amd64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mod ...

versions * BeOS Revision 4 and later for

based computers (where it replaced the

Portable Executable The Portable Executable (PE) format is a file format for executables, object code, DLLs and others used in 32-bit and 64-bit versions of Windows operating systems. The PE format is a data structure that encapsulates the information necessary fo ...

format; the

PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., App ...

version stayed with

Preferred Executable Format The Preferred Executable Format is a file format that specifies the format of executable files and other object code. PEF executables are also called Code Fragment Manager files (CFM). PEF was developed by Apple Computer for use in its classic Ma ...

) *

Haiku is a type of short form poetry originally from Japan. Traditional Japanese haiku consist of three phrases that contain a ''kireji'', or "cutting word", 17 '' on'' (phonetic units similar to syllables) in a 5, 7, 5 pattern, and a ''kigo'', or se ...

, an open source reimplementation of BeOS *

RISC OS RISC OS is a computer operating system originally designed by Acorn Computers Ltd in Cambridge, England. First released in 1987, it was designed to run on the ARM chipset, which Acorn had designed concurrently for use in its new line of Archim ...

Stratus VOS Stratus VOS (Virtual Operating System) is a proprietary operating system running on Stratus Technologies fault-tolerant computer systems. VOS is available on Stratus's ftServer and Continuum platforms. VOS customers use it to support high-volume ...

, in PA-RISC and x86 versions *

SkyOS SkyOS (''Sky Operating System'') is a discontinued prototype commercial, proprietary, graphical desktop operating system written for the x86 computer architecture. As of January 30, 2009 development was halted with no plans to resume its develop ...

* Fuchsia OS * Z/TPF * HPE NonStop OS *

Deos DDC-I, Inc. is a privately held company providing software development of real-time operating systems, software development tools, and software services for safety-critical embedded applications, headquartered in Phoenix, Arizona. It was first cr ...

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

also uses the ELF format, but only for its

Windows Subsystem for Linux Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...

compatibility system.

Game consoles

Some game consoles also use ELF: *

PlayStation Portable The PlayStation Portable (PSP) is a handheld game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on December 12, 2004, in North America on March 24, 2005, and in PAL regions on September 1, 2005, ...

PlayStation Vita The PlayStation Vita (PS Vita, or Vita) is a handheld video game console developed and marketed by Sony Interactive Entertainment. It was first released in Japan on December 17, 2011, and in North America, Europe, and other international territo ...

PlayStation (console) The (abbreviated as PS, commonly known as the PS1/PS one or its codename PSX) is a home video game console developed and marketed by Sony Computer Entertainment. It was released in Japan on 3 December 1994, in North America on 9 September 1995 ...

PlayStation 2 The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October 2000, in Europe on 24 November 2000, and in Australia on 3 ...

PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed by Sony Interactive Entertainment, Sony Computer Entertainment. The successor to the PlayStation 2, it is part of the PlayStation brand of consoles. It was first released on Novemb ...

PlayStation 4 The PlayStation 4 (PS4) is a home video game console developed by Sony Interactive Entertainment. Announced as the successor to the PlayStation 3 in February 2013, it was launched on November 15, 2013, in North America, November 29, 2013 in ...

PlayStation 5 The PlayStation 5 (PS5) is a home video game console developed by Sony Interactive Entertainment. Announced as the successor to the PlayStation 4 in April 2019, it was launched on November 12, 2020, in Australia, Japan, New Zealand, North Ame ...

GP2X The GP2X is a Linux-based handheld video game console and portable media player developed by South Korean company GamePark Holdings. It was released on November 10, 2005, in South Korea only. The GP2X is designed for homebrew developers as wel ...

Dreamcast The is a home video game console released by Sega on November 27, 1998, in Japan; September 9, 1999, in North America; and October 14, 1999, in Europe. It was the first sixth-generation video game console, preceding Sony's PlayStation 2, N ...

GameCube The is a home video game console developed and released by Nintendo in Japan on September 14, 2001, in North America on November 18, 2001, and in PAL territories in 2002. It is the successor to the Nintendo 64 (1996), and predecessor of the Wii ...

Nintendo 64 The (N64) is a home video game console developed by Nintendo. The successor to the Super Nintendo Entertainment System, it was released on June 23, 1996, in Japan, on September 29, 1996, in North America, and on March 1, 1997, in Europe and Au ...

Wii The Wii ( ) is a home video game console developed and marketed by Nintendo. It was released on November 19, 2006, in North America and in December 2006 for most other Regional lockout, regions of the world. It is Nintendo's fifth major ho ...

Wii U The Wii U ( ) is a home video game console developed by Nintendo as the successor to the Wii. Released in late 2012, it is the first eighth-generation video game console and competed with Microsoft's Xbox One and Sony's PlayStation 4. The W ...

PowerPC

Other (operating) systems running on

that use ELF: *

AmigaOS 4 AmigaOS 4 (abbreviated as OS4 or AOS4) is a line of Amiga operating systems which runs on PowerPC microprocessors. It is mainly based on AmigaOS 3.1 source code developed by Commodore, and partially on version 3.9 developed by Haage & Partne ...

, the ELF executable has replaced the prior

Extended Hunk Format Hunk is the executable file format of tools and programs of the Amiga Operating System based on Motorola 68000 CPU and other processors of the same family. This kind of executable got its name from the fact that the software programmed on Amiga ...

(EHF) which was used on Amigas equipped with PPC processor expansion cards. *

MorphOS MorphOS is an AmigaOS-like computer operating system (OS). It is a mixed proprietary and open source OS produced for the Pegasos PowerPC (PPC) processor based computer, PowerUP accelerator equipped Amiga computers, and a series of Freescale dev ...

AROS Aros may refer to: *Aros (Middle-earth), a river in J. R. R. Tolkien's Middle-earth legendarium * Aros, Mull, the location of Aros Castle, a ruined 13th-century castle on the Isle of Mull, Scotland *AROS Research Operating System, a free software i ...

* Café OS (The operating system ran on Wii U)

Mobile phones

Some operating systems for mobile phones and mobile devices use ELF: *

Symbian Symbian is a discontinued mobile operating system A mobile operating system is an operating system for mobile phones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typic ...

OS v9 uses E32Image format that is based on the ELF file format; *

Sony Ericsson Sony Mobile Communications Inc. ( ja, ソニーモバイルコミュニケーションズ株式会社) was a multinational telecommunications company founded on October 1, 2001, as a joint venture between Sony Group Corporation and Ericsson. I ...

, for example, the

W800i The W800 Walkman, released in 2005 (1 August 2005 in the UK), was the first Sony Ericsson phone to use the Walkman brand. The phone features Bluetooth v1.2 (with full Bluetooth 2.0 compliance), Infrared and USB connectivity. Description The W8 ...

, W610, W300, etc. *

Siemens Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad. The principal divisions of the corporation are ''Industry'', '' ...

, the SGOLD and SGOLD2 platforms: from

Siemens C65 The Siemens C65 is a mobile phone announced by Siemens. This phone is under “C-Class” leveling of Siemens for entry levels/ consumer regularly. It was released in March 2004. It weighs 86 g and its dimensions are 100 x 45 x 16 mm ...

to S75 and BenQ-Siemens E71/ EL71; *

Motorola Motorola, Inc. () was an American Multinational corporation, multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent p ...

, for example, the E398, SLVR L7, v360, v3i (and all phone LTE2 which has the patch applied). *

Bada Bada (stylized as bada; Korean: ) is a discontinued mobile operating system developed by Samsung Electronics for devices such as mid- to high-end smartphones and tablet computers. The name is derived from " (bada)", meaning "ocean" or "sea" in ...

, for example, the Samsung Wave S8500. *

Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporatio ...

phones or tablets running the Maemo or the Meego OS, for example, the

Nokia N900 The Nokia N900 is a smartphone made by Nokia. It supersedes the Nokia N810. Its default operating system, Maemo 5, is a Linux-based OS originally developed for the Nokia 770 Internet Tablet. It is the first Nokia device based upon the Texas ...

. * Android uses ELF (shared object) libraries for the

Java Native Interface In software design, the Java Native Interface (JNI) is a foreign function interface programming framework that enables Java code running in a Java virtual machine (JVM) to call and be called by native applications (programs specific to a hardwa ...

. With

Android Runtime Android Runtime (ART) is an application runtime environment used by the Android operating system. Replacing Dalvik, the process virtual machine originally used by Android, ART performs the translation of the application's bytecode into native ...

(ART), the default since Android 5.0 "Lollipop", all applications are compiled into native ELF binaries on installation. Some phones can run ELF files through the use of a

patch Patch or Patches may refer to: Arts, entertainment and media * Patch Johnson, a fictional character from ''Days of Our Lives'' * Patch (''My Little Pony''), a toy * "Patches" (Dickey Lee song), 1962 * "Patches" (Chairmen of the Board song) ...

that adds

assembly code In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence b ...

to the main

firmware In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...

, which is a feature known as ''ELFPack'' in the underground

modding ''Modding'' is a slang expression derived from the English verb " to modify". The term refers to modification of hardware, software, or anything else, to perform a function not originally intended by the designer, or to achieve bespoke specif ...

culture. The ELF file format is also used with the Atmel AVR (8-bit), AVR32 and with

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...

MSP430 The MSP430 is a mixed-signal microcontroller family from Texas Instruments, first introduced on 14 February 1992. Built around a CPU, the MSP430 is designed for low cost and, specifically, low power consumption embedded applications. Applic ...

microcontroller architectures. Some implementations of

Open Firmware Open Firmware is a standard defining the interfaces of a computer firmware system, formerly endorsed by the Institute of Electrical and Electronics Engineers (IEEE). It originated at Sun Microsystems, where it was known as OpenBoot, and has bee ...

can also load ELF files, most notably

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

's implementation used in almost all

machines the company produced.

Specifications

* Generic: **
System V Application Binary Interface
' Edition 4.1 (1997-03-18) **

' (October 2009) *

AMD64 x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mod ...

: **
System V ABI, AMD64 Supplement
' *

Arm In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...

: **
ELF for the ARM Architecture
' *

IA-32 IA-32 (short for "Intel Architecture, 32-bit", commonly called i386) 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 o ...

: **
System V ABI, Intel386 Architecture Processor Supplement
' *

IA-64 IA-64 (Intel Itanium architecture) is the instruction set architecture (ISA) of the Itanium family of 64-bit Intel microprocessors. The basic ISA specification originated at Hewlett-Packard (HP), and was subsequently implemented by Intel in coll ...

: **
Itanium Software Conventions and Runtime Guide
' (September 2000) *

M32R The M32R is a 32-bit RISC instruction set architecture (ISA) developed by Mitsubishi Electric for embedded microprocessors and microcontrollers. The ISA is now owned by Renesas Electronics Corporation, and the company designs and fabricates M32R im ...

: **
M32R ELF ABI Supplement
' Version 1.2 (2004-08-26) * MIPS: **
System V ABI, MIPS RISC Processor Supplement
' **

' (2003-06-11) *

Motorola 6800 The 6800 ("''sixty-eight hundred''") is an 8-bit computing, 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the Motorola 6800 family, M6800 Microcomputer System (latter dubbed ''68xx' ...

: **
Motorola 8- and 16- bit Embedded ABI
' *

PA-RISC PA-RISC is an instruction set architecture (ISA) developed by Hewlett-Packard. As the name implies, it is a reduced instruction set computer (RISC) architecture, where the PA stands for Precision Architecture. The design is also referred to as ...

: **
ELF Supplement for PA-RISC
' Version 1.43 (October 6, 1997) *

: **
System V ABI, PPC Supplement
' **
PowerPC Embedded Application Binary Interface
32-Bit Implementation'' (1995-10-01) **

' Version 1.9 (2004) *

RISC-V RISC-V (pronounced "risk-five" where five refers to the number of generations of RISC architecture that were developed at the University of California, Berkeley since 1981) is an open standard instruction set architecture (ISA) based on estab ...

: **
RISC-V ELF Specification
' *

SPARC SPARC (Scalable Processor Architecture) is a reduced instruction set computer (RISC) instruction set architecture originally developed by Sun Microsystems. Its design was strongly influenced by the experimental Berkeley RISC system developed ...

: **
System V ABI, SPARC Supplement
' *

S/390 The IBM System/390 is a discontinued mainframe product family implementing the ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/90 ...

: **
S/390 32bit ELF ABI Supplement
' *

zSeries IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers. In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mo ...

: **
zSeries 64bit ELF ABI Supplement
' *

OS 9: **
E32Image file format on Symbian OS 9
' The

Linux Standard Base The Linux Standard Base (LSB) was a joint project by several Linux distributions under the organizational structure of the Linux Foundation to standardize the software system structure, including the Filesystem Hierarchy Standard used in the ...

(LSB) supplements some of the above specifications for architectures in which it is specified. For example, that is the case for the System V ABI, AMD64 Supplement.

86open

86open was a project to form consensus on a common

binary file A binary file is a computer file that is not a text file. The term "binary file" is often used as a term meaning "non-text file". Many binary file formats contain parts that can be interpreted as text; for example, some computer document fil ...

format for

and

s on the common

PC compatible IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones. ...

architecture, to encourage software developers to port to the architecture. The initial idea was to standardize on a small subset of Spec 1170, a predecessor of the Single UNIX Specification, and the GNU C Library (glibc) to enable unmodified binaries to run on the x86 Unix-like operating systems. The project was originally designated "Spec 150". The format eventually chosen was ELF, specifically the Linux implementation of ELF, after it had turned out to be a ''de facto'' standard supported by all involved vendors and operating systems. The group began email discussions in 1997 and first met together at the

Santa Cruz Operation The Santa Cruz Operation, Inc. (usually known as SCO, pronounced either as individual letters or as a word) was an American software company, based in Santa Cruz, California, that was best known for selling three Unix operating system variants ...

offices on August 22, 1997. The steering committee was

Marc Ewing Marc Ewing is an American computer engineer and entrepreneur. He is the creator and originator of the Red Hat brand of software, most notably the Red Hat range of Linux operating system distributions. He was involved in the 86open project in t ...

, Dion Johnson, Evan Leibovitch,

Bruce Perens Bruce Perens (born around 1958) is an American computer programmer and advocate in the free software movement. He created The Open Source Definition and published the first formal announcement and manifesto of open source. He co-founded the Open ...

, Andrew Roach,

Bryan Wayne Sparks Caldera was a US-based software company founded in 1994 to develop Linux- and DOS-based operating system products. Caldera Caldera, Inc. was a Canopy-funded software company founded in October 1994 and incorporated on 25 January 1995 by f ...

and

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also c ...

. Other people on the project were Keith Bostic, Chuck Cranor, Michael Davidson, Chris G. Demetriou, Ulrich Drepper, Don Dugger, Steve Ginzburg,

Jon "maddog" Hall Jon "maddog" Hall (born 7 August 1950) is the board chair for the Linux Professional Institute. Career The nickname "maddog" was given to him by his students at Hartford State Technical College, where he was the Department Head of Computer Sc ...

, Ron Holt,

Jordan Hubbard Jordan K. Hubbard (born April 8, 1963) is an open source software developer, authoring software such as the Ardent Window Manager and various other open source tools and libraries before co-founding the FreeBSD project with Nate Williams and Rodn ...

, Dave Jensen, Kean Johnston, Andrew Josey, Robert Lipe, Bela Lubkin, Tim Marsland, Greg Page, Ronald Joe Record, Tim Ruckle, Joel Silverstein, Chia-pi Tien, and Erik Troan. Operating systems and companies represented were BeOS,

BSDI Berkeley Software Design, Inc. (BSDI or, later, BSDi), was a corporation which developed, sold licenses for, and supported BSD/OS (originally known as BSD/386), a commercial and partially proprietary variant of the BSD Unix operating system for ...

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

, SCO and

SunSoft , stylized as SUNSOFT, is a Japanese video game developer and publisher. Sunsoft is the video games division of Japanese electronics manufacturer Sun Corporation. Its U.S. subsidiary operated under the name Sun Corporation of America, though, a ...

. The project progressed and in mid-1998, SCO began developing lxrun, an open-source

compatibility layer In software engineering, a compatibility layer is an interface that allows binaries for a legacy or foreign system to run on a host system. This translates system calls for the foreign system into native system calls for the host system. With so ...

able to run Linux binaries on

OpenServer Xinuos OpenServer, previously SCO UNIX and SCO Open Desktop (SCO ODT), is a closed source computer operating system developed by Santa Cruz Operation (SCO), later acquired by SCO Group, and now owned by Xinuos. Early versions of OpenServer wer ...

, UnixWare, and

. SCO announced official support of lxrun at

LinuxWorld LinuxWorld has various meanings: * LinuxWorld Conference and Expo - a series of Linux conferences worldwide that became OpenSource World in 2009 * LinuxWorld Magazine - a print publication produced from 2003 to 2006 * LinuxWorld.com Internation ...

in March 1999.

Sun Microsystems Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the ...

began officially supporting lxrun for Solaris in early 1999, and later moved to integrated support of the Linux binary format via

Solaris Containers for Linux Applications Solaris Containers (including Solaris Zones) is an implementation of operating system-level virtualization technology for x86 and SPARC systems, first released publicly in February 2004 in build 51 beta of Solaris 10, and subsequently in the fi ...

. With the BSDs having long supported Linux binaries (through a

) and the main x86 Unix vendors having added support for the format, the project decided that Linux ELF was the format chosen by the industry and "declare itself dissolved" on July 25, 1999.

FatELF: universal binaries for Linux

FatELF is an ELF binary-format extension that adds

fat binary A fat binary (or multiarchitecture binary) is a computer executable program or library which has been expanded (or "fattened") with code native to multiple instruction sets which can consequently be run on multiple processor types. This results ...

capabilities. It is aimed for

and other

operating systems. Additionally to the CPU architecture abstraction (

byte order In computing, endianness, also known as byte sex, is the order or sequence of bytes of a word of digital data in computer memory. Endianness is primarily expressed as big-endian (BE) or little-endian (LE). A big-endian system stores the most sig ...

word size In computing, a word is the natural unit of data used by a particular processor design. A word is a fixed-sized datum handled as a unit by the instruction set or the hardware of the processor. The number of bits or digits in a word (the ''word s ...

, CPU

instruction set In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ' ...

etc.), there is the potential advantage of software-platform abstraction e.g., binaries which support multiple kernel ABI versions. , FatELF has not been integrated into the mainline Linux kernel.

References

External links

(archived version)
FreeBSD manual page

Oracle Solaris Linker and Libraries Guide

The ERESI project : reverse engineering on ELF-based operating systems

Linux Today article on 86open
July 26, 1999

October 10, 1997,

Declaration of Ulrich Drepper (PDF)
in

The SCO Group The SCO Group (often referred to SCO and later called The TSG Group) was an American software company in existence from 2002 to 2012 that became known for owning Unix operating system assets that had belonged to the Santa Cruz Operation (the o ...

vs IBM, September 19, 2006
86open and ELF discussion
on

Groklaw ''Groklaw'' is a website that covered legal news of interest to the free and open source software community. Started as a law blog on May 16, 2003 by paralegal Pamela Jones (''"PJ"''), it covered issues such as the SCO-Linux lawsuits, the EU ...

, August 13, 2006 {{Executables Executable file formats