OPEN SOURCE SOFTWARE

Open-source software Part I

Open source software (OSS) is computer software that has its underlying ‘source-code’ made available under a licence. This can allow developers and users to adapt and improve it. Policy on the use of OSS in government was updated in 2004. This briefing explains how OSS works, outlines current and prospective uses and examines recent policy developments. It discusses its advantages and disadvantages and examines factors affecting uptake.

Background
Computer software can be broadly split into two development models (see Box 1 for definitions):
• Proprietary, or ‘closed’ software, owned by a company or individual. Copies of the ‘binary’ are made public; the ‘source-code’ is not usually made public.

• Open source software (OSS), where the source-code is released with the binary. Users and developers can be licenced to use and modify the code, and to distribute any improvements they make.

In practice, software companies often develop both types of software. OSS is developed by an on-going, iterative process where people share the ideas expressed in the source-code. The aim is that a large community of developers and users can contribute to the development of the code, check it for errors and bugs, and make the improved version available to others. Project management software is used to allow developers to keep track of the various versions.

Both OSS and proprietary approaches allow companies to make a profit. Companies developing proprietary software make money by developing software and then selling licences to use the software, for example Microsoft receives a payment for every copy of Windows sold with a personal computer. OSS companies make their money by providing services, such as advising clients on the version that best suits their needs, installing and customising software and development and maintenance.

The software itself may be made available at no cost. There are two main types of OSS licences:
• Berkeley Software Distribution (BSD) Licence: this permits a licencee to ‘close’ a version (by withholding the most recent modifications to the source-code) and sell it as a proprietary product;

• GNU General Public Licence (GNU GPL, or GPL, Box2): under this licence, licencees may not ‘close’ versions. The licencee may modify, copy and redistribute any derivative version, under the same GPL licence. The licencee can either charge a fee for this service or work free of charge.

Box 1. Some Common Definitions
Software is the name given to the programs that run on a computer, e.g. Microsoft Word. Programs are written as text documents, known as ‘source-code’, that contain the readable instructions controlling the program’s operation (written in computer code, such as C++). Software must be transformed, or ‘compiled’, before it can be used by a computer. This is known as the ‘binary’. Once compiled into a binary, a computer application may be used, but cannot be modified and improved unless developers have access to the underlying source-code.

An operating system is the basic software required for a computer to work. Usually all other applications require an operating system in order to work. The most widely used proprietary and open source operating systems are Microsoft Windows and GNU/Linux (page 3) respectively. Software is also required for the desktop and for infrastructure, that is to handle the basic data-processing and connections in a computer network.

Box 2. History of open source and free software
Open source first evolved during the 1970s. Richard Stallman, an American software developer who believes that sharing source-code and ideas is fundamental to freedom of speech, developed a ‘free’ version of the widely used ‘Unix’ operating system. The resulting ‘GNU’ program was released under a specially created General Public Licence (‘GNU GPL’). This was designed to ensure that the source-code would remain openly available to all. It was not intended to prevent commercial usage or distribution. This approach was christened ‘free software’. In this context ‘free’ meant that anyone could modify the software. However, the term ‘free’ was often misunderstood to mean ‘no cost’. Hence ‘open source software’ was coined as a less contentious and more ‘business-friendly’ term.