In distributed computing, an object request broker (ORB) is a piece of middleware software that allows programmers to make program calls from one computer to another, via a network. Distributed computing is decentralised and parallel computing, using two or more computers communicating over a network to accomplish a common objective or task. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

ORBs handle the transformation of in-process data structures to the byte sequence which is transmitted over the network (of course also the reverse transformation). This is called marshalling or serialization. See serial publication for the term in publishing In computer science, serialization means to force one-at-a-time access for the purposes of concurrency control, or to encode a data structure as a sequence of bytes. ... // General characteristics In an older computer science context serialization means to force one-at-a-time access for the purposes of concurrency control. ...

Some ORBs, such as CORBA-compliant systems, use an Interface Description Language (IDL) to describe the data which is to be transmitted on remote calls. Before object-oriented programming (OOP) became mainstream, a similar technology called remote procedure call (RPC) was popular. In computing, Common Object Request Broker Architecture (CORBA) is a standard for software componentry, created and controlled by the Object Management Group (OMG). ... Wikipedia does not yet have an article with this exact name. ... The acronym OOP has multiple meanings: The computer programming paradigm known as Object-oriented programming. ... Remote procedure call (RPC) is a protocol that allows a computer program running on one computer to cause a subroutine on another computer to be executed without the programmer explicitly coding the details for this interaction. ...

In addition to marshalling data, ORBs often expose many more features, such as distributed transactions, directory services or realtime scheduling. A distributed transaction is a database transaction that must be synchronized among multiple participating databases which are distributed among different physical locations. ... A Directory service organizes content in a directory server into a logical and accessible structure. ... An operation within a larger dynamic system is called a real-time operation if the combined reaction- and operation-time of a task is shorter than the maximum delay that is allowed, in view of circumstances outside the operation. ...

In the object oriented languages, the ORB is an object, having methods to connect the objects being served. After such an object is connected to the ORB, the methods of that object become accessible for remote invocations. ORB must also have some means to obtain the network address of the object that has now become remote. The typical ORB also has many other methods.

See also

• CORBA - the Common Object Request Broker Architecture.
• Orbix - An Enterprise-level CORBA ORB
• Orbacus - A source code available, high performance CORBA ORB
• TAO - A source code available Real-time CORBA with TAO(TM) (CORBA ORB)
• DCOM - the Distributed Component Object Model from Microsoft
• RMI - the Remote Method Invocation Protocol from SUN
• RPC - Remote Procedure Call
• SimpleORB - a small, non-CORBA ORB
• Ice - a full-featured, non-CORBA ORB