An object-oriented operating system is an

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

that is designed, structured, and operated using

object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and impl ...

principles. An object-oriented operating system is in contrast to an object-oriented

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine fro ...

or programming framework, which can be run on a non-object-oriented operating system like

DOS DOS (, ) is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, both of which were introduced in 1981. Later compatible syste ...

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user 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, a ...

. There are already object-based language concepts involved in the design of a more typical operating system such as

. While a more traditional language like C does not support object-orientation as fluidly as more recent languages, the notion of, for example, a file,

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

, or

device driver In the context of an operating system, 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, enabli ...

(in Unix, each represented as a

file descriptor In Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a file or other input/output resource, such as a pipe or network socket. File descriptors typically h ...

) can be considered a good example of objects. They are, after all,

abstract data type In computer science, an abstract data type (ADT) is a mathematical model for data types, defined by its behavior (semantics) from the point of view of a '' user'' of the data, specifically in terms of possible values, possible operations on data ...

s, with various methods in the form of

system call In computing, a system call (syscall) is the programmatic way in which a computer program requests a service from the operating system on which it is executed. This may include hardware-related services (for example, accessing a hard disk drive ...

s which behavior varies based on the type of object and which implementation details are hidden from the caller. Object-orientation has been defined as objects +

inheritance Inheritance is the practice of receiving private property, titles, debts, entitlements, privileges, rights, and obligations upon the death of an individual. The rules of inheritance differ among societies and have changed over time. Offi ...

, and inheritance is only one approach to the more general problem of

delegation Delegation is the process of distributing and entrusting work to another person.Schermerhorn, J., Davidson, P., Poole, D., Woods, P., Simon, A., & McBarron, E. (2017). ''Management'' (6th ed., pp. 282–286). Brisbane: John Wiley & Sons Australia. ...

that occurs in every operating system. Object-orientation has been more widely used in the

s of operating systems than in their kernels.

Background

An object is an instance of a class, which provides a certain set of functionalities. Two objects can be differentiated based on the functionalities (or methods) they support. In an operating system context, objects are associated with a resource. Historically, the object-oriented design principles were used in operating systems to provide several protection mechanisms. Protection mechanisms in an operating system help in providing a clear separation between different user programs. It also protects the operating system from any malicious user program behavior. For example, consider the case of user profiles in an operating system. The user should not have access to resources of another user. The object model deals with these protection issues with each resource acting as an object. Every object can perform only a set of operations. In the context of user profiles, the set of operations is limited by privilege level of a user. Present-day operating systems use object-oriented design principles for many components of the system, which includes protection.

Examples

; Athene :Athene is an object-based operating system first released in 2000 by Rocklyte Systems. The user environment was constructed entirely from objects that are linked together at runtime. Applications for Athene could also be created using this methodology and were commonly scripted using the object scripting language Dynamic Markup Language (DML). Objects could have been shared between processes by creating them in shared memory and locking them as needed for access. Athene's object framework was multi-platform, allowing it to be used in Windows and Linux environments for developing object-oriented programs. The company went defunct and the project abandoned sometime in 2009. ; BeOS :

BeOS BeOS is a discontinued operating system for personal computers that was developed by Be Inc. It was conceived for the company's BeBox personal computer which was released in 1995. BeOS was designed for multitasking, multithreading, and a graph ...

was an object-oriented operating system released in 1995, which used objects and the C++ language for the

application programming interface An application programming interface (API) is a connection between computers or between computer programs. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standard that des ...

(API). The kernel was written in C with C++ wrappers in user space. The OS did not see mainstream usage and proved commercially unviable, however it has seen continued usage and development by a small enthusiast community. ; Choices :Choices is an object-oriented operating system developed at the

University of Illinois at Urbana–Champaign The University of Illinois Urbana-Champaign (UIUC, U of I, Illinois, or University of Illinois) is a public land-grant research university in the Champaign–Urbana metropolitan area, Illinois, United States. Established in 1867, it is the f ...

. It is written in C++ and uses objects to represent core kernel components like the

central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ...

(CPU), processes, and so on.

Inheritance Inheritance is the practice of receiving private property, titles, debts, entitlements, privileges, rights, and obligations upon the death of an individual. The rules of inheritance differ among societies and have changed over time. Offi ...

is used to separate the kernel into portable machine-independent classes and small non-portable dependent classes. Choices has been ported to and runs on SPARC,

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 8086 microprocessor and its 8-bit-external-bus variant, the 8088. Th ...

, and

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 ...

. ; ETHOS :ETHOS was an experimental object oriented version of the Oberon System (see below) created by Clemens Szyperski for his PhD Thesis written in

Oberon-2 Oberon-2 is an extension of the original Oberon programming language that adds limited reflective programming (reflection) and object-oriented programming facilities, open arrays as pointer base types, read-only field export, and reintroduces th ...

; GEOS :

PC/GEOS GEOS (later renamed GeoWorks Ensemble, NewDeal Office, and Breadbox Ensemble) is a computer operating environment, graphical user interface (GUI), and suite of application software. Originally released as PC/GEOS, it runs on MS-DOS-based, I ...

is a light-weight object-oriented multitasking graphical operating system with sophisticated window and desktop management featuring scalable fonts. It is mostly written in an object-oriented x86 assembly language dialect and some C/C++ and is designed to run on

(similar to Microsoft Windows up to

Windows Me Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...

). GEOS was developed originally by Berkeley Softworks in 1990, which later became GeoWorks Corporation, and it is continued to be maintained by BreadBox Computer Company. Related

software suite A software suite (also known as an application suite) is a collection of computer programs (application software, or programming software) of related functionality, sharing a similar user interface and the ability to easily exchange data with eac ...

s were named ''Ensemble'' and ''New Deal Office''. Adaptations exist for various palmtops, and 32-bit systems with non-x86-CPUs. ; Haiku :

Haiku is a type of short form poetry that originated in Japan. Traditional Japanese haiku consist of three phrases composed of 17 Mora (linguistics), morae (called ''On (Japanese prosody), on'' in Japanese) in a 5, 7, 5 pattern; that include a ''kire ...

(originally named ''OpenBeOS''), is an open-source replacement for BeOS. It reached its first development milestone in September 2009 with the release of Haiku R1/Alpha 1. The x86 distribution is compatible with BeOS at both source and binary level. Like BeOS, it is written primarily in C++ and provides an object-oriented API. It is actively developed. ; IBM i (OS/400, i5/OS) :IBM introduced

OS/400 IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2 ...

in 1988. This OS ran exclusively on the

AS/400 The IBM AS/400 (Application System/400) is a family of midrange computers from IBM announced in June 1988 and released in August 1988. It was the successor to the System/36 and System/38 platforms, and ran the OS/400 operating system. Lower-cost ...

platform. Renamed

IBM i IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2 ...

in 2008, this operating system and runs exclusively on

Power Systems IBM Power Systems is a family of server computers from IBM that are based on its Power processors. It was created in 2008 as a merger of the System p and System i product lines. History IBM had two distinct POWER- and PowerPC-based hardwar ...

which also can run

AIX Aix or AIX may refer to: Computing * AIX, a line of IBM computer operating systems *Alternate index, for an IBM Virtual Storage Access Method key-sequenced data set * Athens Internet Exchange, a European Internet exchange point Places Belg ...

and

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

. IBM i uses an object-oriented methodology and integrates a database ( Db2 for i). The IBM i OS has a 128-bit unique identifier for each object. ; IBM OS/2 2.0 :IBM's first priority based pre-emptive multitasking, graphical, windows-based operating system included an object-oriented user shell. It was designed for the Intel 80386 that used

virtual 8086 mode In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running ...

with full 32-bit support and was released in 1992.

ArcaOS ArcaOS is a Proprietary software, proprietary operating system based on OS/2, developed and marketed by Arca Noae, LLC under license from IBM. It was first released in 2017 and builds on OS/2 Warp 4.52 by adding support for new hardware, fixing ...

, a new OS/2 based operating system initially called Blue Lion is being developed by Arca Noae. The first version was released in May 2017. ; IBM TopView : TopView was an object-oriented operating environment that loaded on a PC on DOS, and then took control from DOS. At that point it effectively became an object-oriented operating system with an object-oriented API (TopView API). It was IBM's first multi-tasking, window based, object-oriented operating system for the PC led by David C. Morrill and released in February 1985. ; Java-based :Given that Oracle's (formerly

Sun Microsystems Sun Microsystems, Inc., often known as Sun for short, was an American technology company that existed from 1982 to 2010 which developed and sold computers, computer components, software, and information technology services. Sun contributed sig ...

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

is today one of the most dominant object-oriented languages, it is no surprise that Java-based operating systems have been attempted. In this area, ideally, the kernel would consist of the bare minimum needed to support a

Java virtual machine A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally descr ...

(JVM). This is the only component of such an operating system that would have to be written in a language other than Java. Built on the JVM and basic hardware support, it would be possible to write the rest of the operating system in Java; even parts of the system that are more traditionally written in a lower-level language such as C, for example

s, can be written in Java. :Examples of attempts at such an operating system include JavaOS, JOS, JNode, and JX. ; Lisp-based :An object-oriented operating system written in the

Lisp Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized Polish notation#Explanation, prefix notation. Originally specified in the late 1950s, ...

dialect

Lisp Machine Lisp Lisp Machine Lisp is a programming language, a dialect of the language Lisp. A direct descendant of Maclisp, it was initially developed in the mid to late 1970s as the system programming language for the Massachusetts Institute of Technology (MI ...

(and later

Common Lisp Common Lisp (CL) is a dialect of the Lisp programming language, published in American National Standards Institute (ANSI) standard document ''ANSI INCITS 226-1994 (S2018)'' (formerly ''X3.226-1994 (R1999)''). The Common Lisp HyperSpec, a hyperli ...

) was developed at MIT. It was commercialized with Lisp machines from

Symbolics Symbolics, Inc., is a privately held American computer software maker that acquired the assets of the former manufacturing company of the identical name and continues to sell and maintain the Open Genera Lisp (programming language), Lisp sy ...

, Lisp Machines Inc. and

Texas Instruments Texas Instruments Incorporated (TI) is an American multinational semiconductor company headquartered in Dallas, Texas. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog ...

. Symbolics called their operating system

Genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

. It was developed with the

Flavors Flavour or flavor is either the sensory perception of taste or smell, or a flavoring in food that produces such perception. Flavour or flavor may also refer to: Science * Flavors (programming language), an early object-oriented extension to L ...

object-oriented extension of Lisp, then with New Flavors, and then with the

Common Lisp Object System The Common Lisp Object System (CLOS) is the facility for object-oriented programming in American National Standards Institute, ANSI Common Lisp. CLOS is a powerful dynamic programming language, dynamic object system which differs radically from t ...

(CLOS). :Xerox developed several workstations with an operating system written in Interlisp-D. Interlisp-D provided object-oriented extensions like LOOPS and CLOS. :Movitz an
Mezzano
are two more recent attempts at operating systems written in Common Lisp. ; Medos-2 : Medos-2 is a single user, object-oriented operating system made for the

Lilith Lilith (; ), also spelled Lilit, Lilitu, or Lilis, is a feminine figure in Mesopotamian and Jewish mythology, theorized to be the first wife of Adam and a primordial she-demon. Lilith is cited as having been "banished" from the Garden of Eden ...

line of

workstation A workstation is a special computer designed for technical or computational science, scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating syste ...

s (processor:

Advanced Micro Devices Advanced Micro Devices, Inc. (AMD) is an American multinational corporation and technology company headquartered in Santa Clara, California and maintains significant operations in Austin, Texas. AMD is a Information technology, hardware and F ...

(AMD) 2901), developed in the early 1980s at

ETH Zurich ETH Zurich (; ) is a public university in Zurich, Switzerland. Founded in 1854 with the stated mission to educate engineers and scientists, the university focuses primarily on science, technology, engineering, and mathematics. ETH Zurich ran ...

by Svend Erik Knudsen with advice from

Niklaus Wirth Niklaus Emil Wirth ( IPA: ) (15 February 1934 – 1 January 2024) was a Swiss computer scientist. He designed several programming languages, including Pascal, and pioneered several classic topics in software engineering. In 1984, he won the Tu ...

. It is built entirely from modules of the programming language

Modula-2 Modula-2 is a structured, procedural programming language developed between 1977 and 1985/8 by Niklaus Wirth at ETH Zurich. It was created as the language for the operating system and application software of the Lilith personal workstation. It w ...

. It was succeeded at ETH Zurich by the

Oberon Oberon () is a king of the fairy, fairies in Middle Ages, medieval and Renaissance literature. He is best known as a character in William Shakespeare's play ''A Midsummer Night's Dream'', in which he is King of the Fairies and spouse of Titania ...

system (see also below), and a variant named ''

Excelsior Excelsior may refer to: Arts and entertainment Literature and poetry * "Excelsior" (Longfellow), an 1841 poem by Henry Wadsworth Longfellow * "Excelsior", an 1877 picture book in verse by Bret Harte, published as an advertisement for the Sa ...

'' was developed for the Kronos workstation, by the

Academy of Sciences of the Soviet Union The Academy of Sciences of the Soviet Union was the highest scientific institution of the Soviet Union from 1925 to 1991. It united the country's leading scientists and was subordinated directly to the Council of Ministers of the Soviet Union (un ...

, Siberian branch,

Novosibirsk Novosibirsk is the largest city and administrative centre of Novosibirsk Oblast and the Siberian Federal District in Russia. As of the 2021 Russian census, 2021 census, it had a population of 1,633,595, making it the most populous city in Siber ...

Computing Center, Modular Asynchronous Developable Systems (MARS) project, Kronos Research Group (KRG). ; Microsoft Singularity : Singularity is an experimental operating system based on Microsoft's .NET Framework. It is comparable to Java-based operating systems. ; Microsoft Windows NT :

Windows NT Windows NT is a Proprietary software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

is a family of operating systems (including

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, ...

, 8, Phone 8, 8.1,

Windows 10 Windows 10 is a major release of Microsoft's Windows NT operating system. The successor to Windows 8.1, it was Software release cycle#Release to manufacturing (RTM), released to manufacturing on July 15, 2015, and later to retail on July 2 ...

, 10 Mobile,

Windows 11 Windows 11 is a version of Microsoft's Windows NT operating system, released on October 5, 2021, as the successor to Windows 10 (2015). It is available as a free upgrade for devices running Windows 10 that meet the #System requirements, Windo ...

and

Xbox Xbox is a video gaming brand that consists of four main home video game console lines, as well as application software, applications (games), the streaming media, streaming service Xbox Cloud Gaming, and online services such as the Xbox networ ...

) produced by

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

, the first version of which was released in July 1993. It is a

high-level programming language A high-level programming language is a programming language with strong Abstraction (computer science), abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be ea ...

-based, processor-independent,

multiprocessing Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. The ...

multi-user Multi-user software is computer software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leavi ...

operating system. It is best described as

object-based An object-based language is a programming language that provides a construct to encapsulate state and behavior as an object. A language that also supports inheritance or subtyping is classified as object-oriented. Even though object-oriented seems ...

rather than object-oriented as it does not include the full inheritance properties of object-oriented languages. :The Object Manager is in charge of managing NT objects. As part of this responsibility, it maintains an internal

namespace In computing, a namespace is a set of signs (''names'') that are used to identify and refer to objects of various kinds. A namespace ensures that all of a given set of objects have unique names so that they can be easily identified. Namespaces ...

where various operating system components, device drivers, and Win32 programs can store and lookup objects. The NT

Native API The Native API is a lightweight application programming interface (API) used by Windows NT's kernel and user mode applications. This API is used in the early stages of Windows NT startup process, when other components and APIs are still unavail ...

provides routines that allow

user space A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware prote ...

(mode) programs to browse the namespace and query the status of objects located there, but the interfaces are undocumented. NT supports per-object (file, function, and role)

access control list In computer security, an access-control list (ACL) is a list of permissions associated with a system resource (object or facility). An ACL specifies which users or system processes are granted access to resources, as well as what operations are ...

s allowing a rich set of security permissions to be applied to systems and services. WinObj is a Windows NT program that uses the NT Native API (provided by NTDLL.DLL) to access and display information on the NT Object Manager's name space. :; Component Object Model ::On the

user mode A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware prote ...

side of Windows, the

Component Object Model Component Object Model (COM) is a binary-interface technology for software components from Microsoft that enables using objects in a language-neutral way between different programming languages, programming contexts, processes and machines ...

(COM) is an

application binary interface An application binary interface (ABI) is an interface exposed by software that is defined for in-process machine code access. Often, the exposing software is a library, and the consumer is a program. An ABI is at a relatively low-level of a ...

standard for

software components Component-based software engineering (CBSE), also called component-based development (CBD), is a style of software engineering that aims to construct a software system from components that are loosely-coupled and reusable. This emphasizes the sep ...

introduced by

in 1993. It is used to enable

interprocess communication In computer science, interprocess communication (IPC) is the sharing of data between running processes in a computer system. Mechanisms for IPC may be provided by an operating system. Applications which use IPC are often categorized as clients ...

and dynamic

object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an a ...

creation in a large range of

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

s. COM is the basis for several other Microsoft technologies and frameworks, including

Object Linking and Embedding Object Linking and Embedding (OLE) is a proprietary technology developed by Microsoft that allows embedding and linking to documents and other objects. For developers, it brought OLE Control Extension (OCX), a way to develop and use custom user ...

(OLE),

OLE Automation In Microsoft Windows applications programming, OLE Automation (later renamed to simply Automation) is an inter-process communication mechanism created by Microsoft. It is based on a subset of Component Object Model (COM) that was intended for use ...

ActiveX ActiveX is a deprecated software framework created by Microsoft that adapts its earlier Component Object Model (COM) and Object Linking and Embedding (OLE) technologies for content downloaded from a network, particularly from the World Wide W ...

, COM+,

Distributed Component Object Model Distributed Component Object Model (DCOM) is a proprietary Microsoft technology for communication between software components on networked computers. DCOM, which originally was called "Network OLE", extends Microsoft's COM, and provides the co ...

(DCOM), the

Windows shell The Windows shell is the graphical user interface for the Microsoft Windows operating system. Its readily identifiable elements consist of the desktop, the taskbar, the Start menu, the task switcher and the AutoPlay feature. On some versions of ...

DirectX Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with "Direct" ...

, and

Windows Runtime Windows Runtime (WinRT) is a platform-agnostic component and application architecture first introduced in Windows 8 and Windows Server 2012 in 2012. It is implemented in C++ and officially supports development in C++ (via C++/WinRT, C++/CX ...

. OLE is a

proprietary {{Short pages monitor