DCE/RPC

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DCE/RPC, short for "Distributed Computing Environment / Remote Procedure Calls", is the remote procedure call system developed for the Distributed Computing Environment (DCE). This system allows programmers to write distributed software as if it were all working on the same computer, without having to worry about the underlying network code.

In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in a different address space, which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction. That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote. This is a form of client–server interaction, typically implemented via a request–response message-passing system. In the object-oriented programming paradigm, RPC calls are represented by remote method invocation (RMI). The RPC model implies a level of location transparency, namely that calling procedures is largely the same whether it is local or remote, but usually they are not identical, so local calls can be distinguished from remote calls. Remote calls are usually orders of magnitude slower and less reliable than local calls, so distinguishing them is important.

In computing, the Distributed Computing Environment (DCE) software system was developed in the early 1990s from the work of the Open Software Foundation (OSF), a consortium that included Apollo Computer, IBM, Digital Equipment Corporation, and others. The DCE supplies a framework and a toolkit for developing client/server applications. The framework includes:

Contents

History

DCE/RPC was commissioned by the Open Software Foundation in a "Request for Technology" (1993 David Chappell).[ when? ] One of the key companies that contributed was Apollo Computer, who brought in NCA - "Network Computing Architecture" which became Network Computing System (NCS) and then a major part of DCE/RPC itself. The naming convention for transports that can be designed (as architectural plugins) and then made available to DCE/RPC echoes these origins, e.g. ncacn_np (SMB Named Pipes transport); ncacn_tcp (DCE/RPC over TCP/IP) and ncacn_http to name a small number.

The Open Software Foundation (OSF) was a not-for-profit organization founded in 1988 under the U.S. National Cooperative Research Act of 1984 to create an open standard for an implementation of the UNIX operating system.

Apollo Computer Inc., founded 1980 in Chelmsford, Massachusetts by William Poduska and others, developed and produced Apollo/Domain workstations in the 1980s. Along with Symbolics and Sun Microsystems, Apollo was one of the first vendors of graphical workstations in the 1980s. Like computer companies at the time and unlike manufacturers of IBM PC compatibles, Apollo produced much of its own hardware and software.

The Network Computing System (NCS) was an implementation of the Network Computing Architecture (NCA). It was created at Apollo Computer in the 1980s. It comprised a set of tools for implementing distributed software applications, or distributed computing.

DCE/RPC's history is such that it's sometimes cited[ by whom? ] as an example of design by committee. It is also frequently noted for its complexity, however this complexity is often a result of features that target large distributed systems and which are often unmatched by more recent RPC implementations such as SOAP.

Design by committee is a disparaging term for a project that has many designers involved but no unifying plan or vision.

SOAP Messaging protocol for web services

SOAP is a messaging protocol specification for exchanging structured information in the implementation of web services in computer networks. Its purpose is to provide extensibility, neutrality and independence. It uses XML Information Set for its message format, and relies on application layer protocols, most often Hypertext Transfer Protocol (HTTP) or Simple Mail Transfer Protocol (SMTP), for message negotiation and transmission.

Software license

Previously, the DCE source was only available under a proprietary license. As of January 12, 2005, it is available under a recognized open source license (LGPL), which permits a broader community to work on the source to expand its features and keep it current. The source may be downloaded over the web. The release consists of about 100 ".tar.gz" files that take up 170 Megabytes. (Note that they include the PostScript of all the documentation, for example.)

The Open Group has stated it will work with the DCE community to make DCE available to the open source development community, as well as continuing to offer the source through The Open Group’s web site. [1]

DCE/RPC's reference implementation (version 1.1) was previously available under the BSD-compatible (Free Software) OSF/1.0 license, and is still available for at least Solaris, AIX and VMS.

DCE is also still available under the previous non open-source license terms from the Open Group website.

Uses

It was used in the UK's National Insurance Recording System (NIRS/2). [2]

It is used by:

Alternate versions and implementations

Books

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References

  1. ↑ News | The Open Group
  2. ↑ The Open Group, CASE STUDY : NIRS2 Archived 2005-11-23 at the Wayback Machine , Winter 1996
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