Written by: Lotte Mygind, Rune Hylsberg Jacobsen and Oskar Swirtun
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Ericsson is adapting its products and work processes to take advantage of opportunities afforded by open-source software. In particular, the Linux operating system (OS) has become an important component for Ericsson.
The authors describe the use of Linux and open-source software in Ericsson products and how they benefit Ericsson's customers. They also touch on the characteristics of open-source software and present a new Linux-based building block for Ericsson's Integrated Site applications.
Background
The communications industry is moving toward systems that are based on modular and common, off-the-shelf hardware and software components. The underpinnings of this transition are open standards and architectures(Box A, Item I).
Open architectures and the standardization of interfaces between associated components are nothing new. What is new, however, with regard to the technological trend to strengthen the notion of openness, is the use of open-source software, which implies that many components contain open-source software supplemented with common, reusable components.
This trend is motivated by vendor and operator emphasis on reducing the costs and risks of development. Open standards ensure portability and interoperability between various components from different providers. For example, the open standards described by organizations such as the IEEE, IETF, and SA Forum are already widely accepted and in use. Likewise, the Linux OS has taken on an important role as a carrier-grade operating system. Figure 1illustrates the shift toward standards-based layers of composition.
What is open source?
The term open sourcerefers to software whose underlying source code is either delivered together with the software or can easily be obtained, for instance, via the internet. Anybody may use, modify, redistribute or sell open-source software. The idea behind an open source is that the process of having many people read, modify, test and debug it should also improve the source. The mere availability of source code is not enough to qualify as open source, however. For example, Microsoft's shared source prohibits commercial use of modified code. The Open Source Initiative (OSI) maintains a formal definition of open source (Box A, Item II).
Proprietary licenses, by contrast, often put restrictions on the use and distribution of software. They generally also deny users access to the source code, and users are frequently required to register and pay for the software.
Some open-source licenses require that modified versions of the software must be licensed in a special way to prevent it from being used as proprietary, closed-source software. A prime example is the GNU General Public License (GPL), which stipulates that works derived from it must also be licensed as open source under the GPL license (Box A, Item III). Because the GPL transfers to derived works, software development companies have complained that the use of GPL software could transform their products into freeware that can be copied by competitors.
The definition of free software is slightly more restrictive than the definition of open source, but the differences are minor. The main difference lies in the political and philosophical approach of the Free Software Foundation (FSF) versus the pragmatic approach of the OSI, which promotes open source for its technical qualities. "Free" refers to freedom of use, not cost. The FSF maintains the definition of free software.
In recent years, there has been greater understanding of GPL in the commercial world, and the legal interpretation has grown clearer. As a consequence, GPL software is now found in numerous commercial products.
The processes used in open source development projects differ from those used in traditional commercial software organizations. In fact, some people claim that these processes are superior to traditional development processes (Box A, Item IV).
