Lesson Objectives Aims Key Words To know the difference between open and closed source software. Key Words

Open Source Its open Closed Source It’s closed

Source Source code is the raw program code for a piece of software ALL software, regardless of whether it is open or closed is created from source code

Closed source Closed Source Proprietary Updated and modified by one organisation Fixed functionality – no ability or right to modify Usually sold for profit (can be freely released) Tight controls on modifications Can take longer to fix/may never be fixed (support) Protects intellectual property/patents Closed source

Open Source Open Source Freely available code base – can be modified by anyone Updated and modified by one or more people Code can be “forked” – adapted to any use Cannot usually be sold for profit Loose control - requires greater community coordination No guarantee of support – quick fixes or none at all? No royalties for intellectual property Open Source

Don’t get confused Open source != Free Free != Open Source Apps can be free – but closed source – how do they make money?

GNU GNU public license Open source still needs a license Why?

Examples of open source Black Mesa Libre Office Linux Firefox Remakes of old games – OpenTTD, CorsixTH, some emulators

Review/Success Criteria You should know: The difference between open and closed source The difference between free and open source! How software can be licensed