Open source software is software which can be used, modified and improved by anyone and can be redistributed freely.

This differs from proprietary software which is supplied under a licence agreement which may require a fee to use the software, or may limit the number of machines the software can be used on and which usually prohibits any copying or redistribution. Open source software is made available under a different type of licence that allows users to use, copy, redistribute and modify the source code. Software is considered to be “open source” if its source code is available under a licence approved by the Open Source Initiative (OSI). More information is available in the licences section.

When we refer to open source software as ‘free’ software we do not mean the free trials or free cut-down versions of proprietary software you may be familiar with, nor software which is supplied free of charge (known as “freeware”) - although in practice most open source software is free in this sense as well. “Free” in the definition of open source software refers to programs where the computer code which creates the software is made available to everyone with few or no restrictions.

For software to be considered “free”, it must allow four fundamental freedoms first identified by the Free Software Foundation.

• The freedom to run the software for any purpose.
• The freedom to study and modify the software.
• The freedom to copy the software.
• The freedom to improve the software.

The two concepts, “free” and “open source” are closely related: the OSI is an attempt to codify “software freedom” into a copyright licence. For this reason you will also see Open Source Software referred to as Free Software or even FOSS or FLOSS. FOSS is Free, Open Source Software, FLOSS Free, Libre Open Source Software. Libre is included to make the distinction between being free of cost/charge and being free as in the freedoms listed above. Open Source Software is usually (but not necessarily) free of cost at the point of acquisition but it is not necessarily free of cost in terms of support (see the Getting Started with Open Source section for more information).

This open approach means that anyone can study and alter the source code and therefore contribute to the development process.

Development of open source software

The open availability of source code results in a very different development model to proprietary software. Proprietary software is typically created by teams of developers paid by companies to create programs which are sold to users to make a profit. The company will have made an investment in the development of the code and it is in their interest to protect this code and the ideas contained within it. It will not necessarily be in the company's interest to ensure their software is compatible with other companies' software or hardware.

Open source software, on the other hand, is developed using an open and collaborative approach where the outcomes of this joint effort are made available without charge. The program code is not kept closed, but is published for others to study and improve as part of this spirit of openness and collaboration.

Open source projects are usually initiated by an individual or small group of people with an idea for software they want to develop. They start writing the code to bring the idea into reality, and will often make an early version of the application available to demonstrate how the software will work (hence the open source mantra, “release early, release often”). They then make the code freely available so others can join in the development process, for example by contributing their own ideas for features and improvements, working on bug fixes and amending and developing the source code to incorporate new ideas.

This can result in a very rapid development process as more and more developers get involved and start contributing. Teams can become large and global as they communicate via the web; communities of developers and users are formed around the program with everyone sharing ideas and information with the common goal of making the program better and more stable, more capable, more useful.

Developers often come from a wide variety of countries leading to the creation of localised versions in many different languages.

Types of open source software

There are many thousands of open source projects covering a wide spectrum of computing tasks. A website that acts as a repository for over 100,000 open source projects, http://sourceforge.net, shows just how large and diverse the open source world is. The projects listed there are all in different stages of development and therefore vary in stability. Some projects inspire a large amount of contribution and become alternatives to well know proprietary applications; some projects remain small and are focused on very specific tasks.

A lot of projects are of interest mainly to software developers and other IT professionals. If you are interested in exploring more specialised OSS applications, sourceforge is a great place to start, but we will be focusing mainly on the larger projects which are further down the development process and provide viable alternatives to proprietary software. For example OpenOffice.org (a suite of office tools) is used as a free and open source alternative to Microsoft Office.

For more information on the type of software available as open source visit our directory.

Benefits of open source software

The main benefits of open source software for most users are that there are no restrictions on use, and that the software is usually free to acquire. You can install the programs on as many computers as you like without it costing anything. Your students may also install the software at home so they can use the programs legally without paying, enabling them to use the packages for homework. It’s important to note, however, that the licence fee is not the only cost associated with the ownership of computer software; there are also costs for support and training and sometimes for maintaining the software. This is referred to as the total cost of ownership (TCO) reflecting how much it actually costs to run software when you factor in all the associated costs. Similar factors apply, of course, when working out the TCO of proprietary software.

It’s important to think about these factors when considering the benefits of moving to open source software and to work out if it really does provide the cost benefits that the free price tag might imply.

Another benefit of open source software is that it frees the user from the ‘vendor lock in’ associated with many proprietary programs. Lock in is where a company makes software incompatible with that of their rivals forcing the user to stick with one company's programs. Open source software tends to use open standards thus improving compatibility between software packages. What's more, if the software's source code is open, it is much easier for other programs to be implemented in a compatible manner.

Using open source software

You may be concerned that you will need to have a lot of technical knowledge to start using open source software and will have to learn a completely new way of doing things when you move away from a software package that you’re familiar with. Open source software is usually very similar to its proprietary counterparts so you should encounter a similar interface when you first launch the program. Skills learnt using proprietary software can be transferred to open source software as most of the features are broadly similar. You won’t feel like you’re having to start from scratch but may need a little time to get used to small differences in the way that programs function.

For example OpenOffice.org is a free suite of Office tools. It has the same core components as proprietary options, such as a word processor, spreadsheet and presentation builder. The programs function in a very similar way to proprietary alternatives, for example the way in which you format text in the word processor or enter data into cells in the spreadsheet. If you are teaching students how to use a spreadsheet they will be able to learn all of the important concepts from OpenOffice.org which can then be applied to other spreadsheet software packages.

What programs are available as open source?

There is a very wide range in most categories of computer software. They include office tools (eg wordprocessing, spreadsheets, presentation, desktop publishing, databases), internet tools (eg e-mail, browers), web-based applications (eg content management systems, information management systems, VLEs), graphics, video and audio tools, curriculum applications, utilities and operating systems. There is an open source alternative to most of the major applications. If you want to get an idea of the types of open source software that are available and to find alternatives to specific proprietary products there are resources on the web that allow you to do just that, such as http://www.osalt.com/

Some open source software is designed to work on a desktop computer and others, such as Moodle, are web based and run on a web server.

Our directory lists some of the main open source applications.

How can I get support?

Support for open source software is usually provided online via the project website. The big open source projects, such as Moodle or Drupal, have very active online communities where you can find the answers to most of your questions. People are usually very keen to help other users. Other sources of support include

books - many of the well established projects have manuals for their software;

discussion forums on this site are being established to enable peer to peer support for users of open source software;

many companies offer support for open source software; we will shortly be developing a database of suppliers and other companies who provide installation, training, support and maintenance services.

How do I start using open source software?

If you want to try out open source software for yourself there are several ways in which you can do so, ranging from trying out web based software using a free trial area to downloading and installing packages to your own computer. Information on this is available in the following sections:

How to obtain Open Source Applications

Getting started with open source

Look at an article "What is open source software?" on the OSS-Watch site, a service provided for higher and further education: http://www.oss-watch.ac.uk/resources/opensourcesoftware.xml

Read a more detailed article by Ian Lynch from Schoolforge UK What is open source and why schools should be interested in it (PDF format 1.4MB)