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

2. Open Source
Its open
Closed Source
It’s closed

3. 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

4. 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

5. 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

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

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

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

9. 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