Open source software was the subject of Chris' 2013 TEDx talk and he continues to use it wherever possible for teaching and professional work.
What is "open source"? Software which is provided by its developers free from both monetary cost and many licensing restrictions. The "open" part means that the source code is publicly available for inspection, copying, and amendment. This means - as long as you download the software from the official source - that it cannot contain malware, as someone would have found it in the code.
For a long time open source software (sometimes known as FOSS, for Free and Open Source Software) was far less capable than its commercial equivalents. In several areas - operating systems, office productivity, digital modeling and animation, and video editing - this is now no longer the case. The Linux operating system, for example, now powers most of the internet. Commercial software has more features, perhaps - but it's also more bloated, expensive, and frequently has to be kept current in order to open files made in the latest versions.
This is a list of current open source software that we recommend.