Inter-Language Unification or ILU is a method for computer systems to exchange data, bridging differences in the way systems represent the various kinds of data. Even if two systems run on the same computer, or on identical computer hardware, many differences arise from the use of different

computer language A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a compu ...

s to build the systems. The

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 ai ...

interfaces Interface or interfacing may refer to: Academic journals * Interface (journal), ''Interface'' (journal), by the Electrochemical Society * ''Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Lin ...

provided by ILU hide

implementation Implementation is the realization of an application, or execution of a plan, idea, model, design, specification, standard, algorithm, or policy. Industry-specific definitions Computer science In computer science, an implementation is a realiza ...

distinctions between different

languages Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of met ...

, between different

address space In computing, an address space defines a range of discrete addresses, each of which may correspond to a network host, peripheral device, disk sector, a memory cell or other logical or physical entity. For software programs to save and retrieve st ...

s, and between

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 ...

types. ILU can be used to build multi-lingual

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of pro ...

libraries A library is a collection of materials, books or media that are accessible for use and not just for display purposes. A library provides physical (hard copies) or digital access (soft copies) materials, and may be a physical location or a vir ...

("class libraries") with well-specified language-independent interfaces. It can also be used to implement

distributed systems A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...

. It can also be used to define and document interfaces between the

modules Broadly speaking, modularity is the degree to which a system's components may be separated and recombined, often with the benefit of flexibility and variety in use. The concept of modularity is used primarily to reduce complexity by breaking a sy ...

of non-distributed programs. ILU interfaces can be specified in either the Object Management Group's

CORBA The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between sys ...

Interface Definition Language interface description language or interface definition language (IDL), is a generic term for a language that lets a program or object written in one language communicate with another program written in an unknown language. IDLs describe an inter ...

(OMG IDL), or ILU's Interface

Specification Language A specification language is a formal language in computer science used during systems analysis, requirements analysis, and systems design to describe a system at a much higher level than a programming language, which is used to produce the executa ...

(ISL).

History

ILU was developed as 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 sof ...

project at the

Xerox Xerox Holdings Corporation (; also known simply as Xerox) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox is headquartered in Norwalk, Connecticut (ha ...

Palo Alto Palo Alto (; Spanish for "tall stick") is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto. The city was estab ...

Research Center (

Xerox PARC PARC (Palo Alto Research Center; formerly Xerox PARC) is a research and development company in Palo Alto, California. Founded in 1969 by Jacob E. "Jack" Goldman, chief scientist of Xerox Corporation, the company was originally a division of Xero ...

) from 1991 until 2000. The last release was 2.0beta1. From 1997 to 2000, ILU was used as the foundation for experimental work on a "next generation"

HTTP protocol The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...

by the

World Wide Web Consortium The World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web. Founded in 1994 and led by Tim Berners-Lee, the consortium is made up of member organizations that maintain full-time staff working to ...

's HTTP-NG activity. As a result of this work, a particularly efficient experimental RPC protocol called
w3ng
was developed, along with a way of efficiently multiplexing a single

TCP TCP may refer to: Science and technology * Transformer coupled plasma * Tool Center Point, see Robot end effector Computing * Transmission Control Protocol, a fundamental Internet standard * Telephony control protocol, a Bluetooth communication s ...

connection into multiple channels in both directions, called
w3mux
. Th

were presented at the 2000

World Wide Web Conference The ACM Web Conference (formerly known as International World Wide Web Conference, abbreviated as WWW) is a yearly international academic conference on the topic of the future direction of the World Wide Web. The first conference of many was hel ...

Features

The last release supported the

programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...

C++ C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...

(Corba2 mapping),

ANSI C ANSI C, ISO C, and Standard C are successive standards for the C programming language published by the American National Standards Institute (ANSI) and ISO/IEC JTC 1/SC 22/WG 14 of the International Organization for Standardization (ISO) and the ...

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

, and

Common Lisp Common Lisp (CL) is a dialect of the Lisp programming language, published in ANSI standard document ''ANSI INCITS 226-1994 (S20018)'' (formerly ''X3.226-1994 (R1999)''). The Common Lisp HyperSpec, a hyperlinked HTML version, has been derived fro ...

. Contributed support was also available for

Modula-3 Modula-3 is a programming language conceived as a successor to an upgraded version of Modula-2 known as Modula-2+. While it has been influential in research circles (influencing the designs of languages such as Java, C#, and Python) it has not be ...

Guile Scheme GNU Ubiquitous Intelligent Language for Extensions (GNU Guile) is the preferred extension language system for the GNU Project and features an implementation of the programming language Scheme. Its first version was released in 1993. In addition ...

, and

Perl 5 Perl is a family of two High-level programming language, high-level, General-purpose programming language, general-purpose, Interpreter (computing), interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it ...

. ILU has been installed on most flavors of UNIX (

SunOS SunOS is a Unix-branded operating system developed by Sun Microsystems for their workstation and server computer systems. The ''SunOS'' name is usually only used to refer to versions 1.0 to 4.1.4, which were based on BSD, while versions 5.0 and l ...

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 ...

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 ...

AIX Aix or AIX may refer to: Computing * AIX, a line of IBM computer operating systems *An Alternate Index, for a Virtual Storage Access Method Key Sequenced Data Set *Athens Internet Exchange, a European Internet exchange point Places Belgium ...

, OSF,

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 ...

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 ...

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 ...

LynxOS The LynxOS RTOS is a Unix-like real-time operating system from Lynx Software Technologies (formerly "LynuxWorks"). Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility. Lyn ...

SCO Unix 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 were ...

, etc.) and

MS-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 ser ...

(3.1, 95, NT). It supported both threaded (

POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming interf ...

, Solaris, NT, Franz ACL, PPCR, Modula-3) and event-loop ( Xt, Tk,

XView XView is a widget toolkit from Sun Microsystems introduced in 1988. It provides an OPEN LOOK user interface for X Window System applications, with an object-oriented application programming interface (API) for the C programming language. Its in ...

) operation. One of the implementation goals was to maximize compatibility with existing

open standard An open standard is a standard that is openly accessible and usable by anyone. It is also a prerequisite to use open license, non-discrimination and extensibility. Typically, anybody can participate in the development. There is no single definition ...

s. As a result, ILU provided support for use of the OMG CORBA IDL interface description language, and can be thought of as a CORBA ORB system (though with omissions from and extensions to the CORBA spec). ILU also included a self-contained implementation of ONC RPC, and it was possible to describe and use existing RPC services as ILU objects. ILU also included a self-contained implementation of the World Wide Web's Hypertext Transfer Protocol (HTTP), and could thus be used to implement object-oriented

web browser A web browser is application software for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on ...

s and servers. Communication security was provided by GSS-based context negotiation and on-the-wire encryption.

External links

*The ILU sources are available free from ftp://ftp.parc.xerox.com/pub/ilu/ilu.html{{Dead link, date=January 2020 , bot=InternetArchiveBot , fix-attempted=yes . Computer languages Component-based software engineering Inter-process communication Object models Object request broker Object-oriented programming

History

Features

See also

External links