Binary-code compatibility (binary compatible or object-code-compatible) is a property of a

computer system A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...

, meaning that it can run the same executable code, typically

machine code In computer programming, machine code is any low-level programming language, consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Each instruction causes the CPU to perform a ve ...

for a

general-purpose computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...

CPU 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, a ...

, that another computer system can run.

Source-code compatibility Source-code compatibility (source-compatible) means that a program can run on computers (or operating systems), independently of binary-code compatibility and that the source code is needed for portability. The source code must be compiled befor ...

, on the other hand, means that recompilation or

interpretation Interpretation may refer to: Culture * Aesthetic interpretation, an explanation of the meaning of a work of art * Allegorical interpretation, an approach that assumes a text should not be interpreted literally * Dramatic Interpretation, an event ...

is necessary before the program can be run on the compatible system. For a compiled program on a general operating system, binary compatibility often implies that not only the CPUs ( instruction sets) of the two computers are binary compatible, but also that interfaces and behaviours of the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

(OS) and

application programming interface An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

s (APIs), and 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 ...

s (ABIs) corresponding to those APIs, are sufficiently equal, i.e. "compatible". A term like

backward-compatible Backward compatibility (sometimes known as backwards compatibility) is a property of an operating system, product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system, especially in ...

usually implies object-code compatibility. This means that newer computer hardware and/or software has (practically) every feature of the old, plus additional capabilities or performance. Older executable code will thus run unchanged on the newer product. For a compiled program running directly on a CPU under an OS, a "binary compatible operating system" primarily means

(ABI) compatibility with another system. However, it also often implies that APIs that the application depends on, directly or indirectly (such as the

Windows API The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. The name Windows API collectively refers to several different platform implementations th ...

, for example), are sufficiently similar. Hardware (besides the CPU, such as for graphics) and peripherals that an application accesses may also be a factor for full compatibility, although many hardware differences are hidden by modern APIs (often partly supplied by the OS itself and partly by specific

device driver In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and o ...

s). In other cases, a general

porting In software engineering, porting is the process of adapting software for the purpose of achieving some form of execution in a computing environment that is different from the one that a given program (meant for such execution) was originally desi ...

of the software must be used to make non-binary-compatible programs work. Binary compatibility is a major benefit when developing computer programs that are to be run on multiple OSes. Several

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, ...

-based OSes, such as

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 ...

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 ava ...

, offer binary compatibility with more popular OSes, such as

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, whi ...

-derived ones, since most binary executables are not commonly distributed for such OSes. Most OSes provide binary compatibility, in each version of the OS, for most binaries built to run on earlier versions of the OS. For example, many executables compiled for

Windows 3.1 Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series ran as a shell on top of MS-DOS. Codenamed Janus, Windows ...

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturi ...

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It was the direct successor to Windows NT 4.0, and was released to manufacturing on December 15, 1999, and was offici ...

can also be run on

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was release to manufacturing, released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Wind ...

Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...

, and many applications for

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

ran on much newer versions of Windows up to Windows 10 for as long as the

NTVDM Virtual DOS machines (VDM) refer to a technology that allows running 16-bit/32-bit DOS and 16-bit Windows programs when there is already another operating system running and controlling the hardware. Overview Virtual DOS machines can operate eit ...

was supported.

Binary compatible hardware

For a digital processor implemented in hardware, binary compatibility means that (a large subset of)

produced for another processor can be correctly executed and has (much) the same effect as on the other processor. This is quite common among many processor families, although it is rather uncommon among the ubiquitous small

embedded system An embedded system is a computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is ''embedded ...

s built around such processors. Full machine code compatibility would here imply exactly the same layout of interrupt service routines, I/O-ports,

hardware register In digital electronics, especially computing, hardware registers are circuits typically composed of flip flops, often with many characteristics similar to memory, such as: * The ability to read or write multiple bits at a time, and * Using an ...

s, counter/timers, external interfaces and so on. For a more complex embedded system using more

abstraction layer In computing, an abstraction layer or abstraction level is a way of hiding the working details of a subsystem. Examples of software models that use layers of abstraction include the OSI model for network protocols, OpenGL, and other graphics libr ...

s (sometimes on the border to a general computer, such as a mobile phone), this may be different.

Binary compatible operating systems

Binary compatible operating systems are OSes that aim to implement binary compatibility with another OS, or another variant of the same brand. This means that they are ABI-compatible (for

). As the job of an OS is to run programs, the

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 ...

s running the OSes have to be the same or compatible. Otherwise, programs can be employed within a CPU emulator or a faster

dynamic translation In computer science, dynamic recompilation is a feature of some emulators and virtual machines, where the system may recompile some part of a program during execution. By compiling during execution, the system can tailor the generated code to ...

mechanism to make them compatible. For example, the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...

is not compatible with Windows. This does not mean that Linux can't be binary compatible with Windows applications. Additional software,

Wine Wine is an alcoholic drink typically made from Fermentation in winemaking, fermented grapes. Yeast in winemaking, Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different ...

, is available that does that to some degree. The

ReactOS ReactOS is a free and open-source operating system for amd64/i686 personal computers intended to be binary-compatible with computer programs and device drivers made for Windows Server 2003 and later versions of Windows. ReactOS has been not ...

development effort seeks to create an

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized so ...

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, n ...

OS that is binary compatible with

Microsoft's Microsoft Corporation is an American multinational corporation, multinational technology company, technology corporation producing Software, computer software, consumer electronics, personal computers, and related services headquartered at th ...

Windows NT Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system. The first version of Win ...

family of OSes using Wine for application compatibility and reimplementing the Windows kernel for additional compatibility such as for drivers whereas Linux would use Linux drivers not Windows drivers.

and other members of the BSD family have binary compatibility with the

usermode In computer science, hierarchical protection domains, often called protection rings, are mechanisms to protect data and functionality from faults (by improving fault tolerance) and malicious behavior (by providing computer security). Comput ...

by translating Linux system calls into BSD ones. This enables the application and libraries code that run on

-based OSes to be run on BSD as well. Note that a binary compatible OS is different from running an alternative OS through

virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, stor ...

emulation Emulation may refer to: *Emulation (computing), imitation of behavior of a computer or other electronic system with the help of another type of system :*Video game console emulator, software which emulates video game consoles *Gaussian process em ...

, which is done to run software within the alternative OS in the case when the host OS isn't compatible. Sometimes virtualization is provided with the host OS (or such software can be obtained), which effectively makes the host OS compatible with programs. For example,

Windows XP Mode Windows Virtual PC (successor to Microsoft Virtual PC 2007, Microsoft Virtual PC 2004, and Connectix Virtual PC) is a Hardware virtualization, virtualization program for Microsoft Windows. In July 2006, Microsoft released the Windows version f ...

for

allows users to run a

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A ...

version of Windows 7 and enable old software to still work in a

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 calculati ...

virtual machine running

; VMware Workstation/ VMware Fusion,

Parallels Workstation Parallels Workstation is the first commercial software product released by Parallels, Inc., a developer of desktop and server virtualization software. The Workstation software consists of a virtual machine suite for Intel x86-compatible computer ...

, and

Windows Virtual PC Windows Virtual PC (successor to Microsoft Virtual PC 2007, Microsoft Virtual PC 2004, and Connectix Virtual PC) is a virtualization program for Microsoft Windows. In July 2006, Microsoft released the Windows version free of charge. In August ...

allow other OSes to be run on Windows, Linux, and macOS. For another example,

Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...

on 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– IBM– ...

had the ability to run

Mac OS 9 Mac OS 9 is the ninth major release of Apple's classic Mac OS operating system which was succeeded by Mac OS X (renamed to OS X in 2011 and macOS in 2016) in 2001. Introduced on October 23, 1999, it was promoted by Apple as "The Best Internet ...

and earlier application software through

Classic A classic is an outstanding example of a particular style; something of lasting worth or with a timeless quality; of the first or highest quality, class, or rank – something that exemplifies its class. The word can be an adjective (a ''c ...

—but this did not make Mac OS X a binary compatible OS with Mac OS 9. Instead, the Classic environment was actually running Mac OS 9.1 in a

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

, running as a normal process inside of Mac OS X.

References

External links

KDE Techbase Policies
– a compendium of C++ development rules of thumb (wit
some examples
for not breaking binary compatibility between releases of a library.
ABI Analysis Tools
a set of open-source tools for analysis of ABI and backward binary compatibility implementing KDE Techbase Policies {{Application binary interface Backward compatibility Computing terminology de:Kompatibilität (Technik)#Binärkompatibilität

Binary compatible hardware

Binary compatible operating systems

See also

References

External links