Open & Closed Source Software
Software can be distributed with its source code available (open-source) or hidden (closed-source). Each model has distinct advantages and implications for users, developers, and organizations.
Learning Objectives
- 11.1.3.2 Describe the specifics of open-source software
- 11.1.3.3 Describe the specifics of closed-source software
Conceptual Anchor
The Restaurant Analogy
Open-source is like a restaurant that shares its recipes — anyone can cook the dish, improve the recipe, or share it with friends. Closed-source is like a secret recipe — you enjoy the food but can't see how it's made, modify it, or share the recipe.
Rules & Theory
Comparison
| Feature | Open Source | Closed Source |
|---|---|---|
| Source code | Publicly available | Hidden/proprietary |
| Cost | Usually free | Usually paid (license fee) |
| Modification | Anyone can modify and redistribute | Only the company can modify |
| Support | Community forums, documentation | Professional support team |
| Security | Many eyes = bugs found faster | Security through obscurity |
| Updates | Community-driven, frequent | Scheduled by company |
| Examples | Linux, Firefox, LibreOffice, Python | Windows, macOS, Photoshop, MS Office |
Advantages & Disadvantages
| Advantages | Disadvantages | |
|---|---|---|
| Open Source | Free, customizable, transparent, faster bug fixes, no vendor lock-in | Less professional support, inconsistent UI, may be complex to install |
| Closed Source | Professional support, polished UI, tested/certified, comprehensive docs | Expensive, no customization, vendor lock-in, slower bug fixes |
Types of Licenses
| License | Type | Key Rule |
|---|---|---|
| GPL | Open source | Derivative works must also be open source |
| MIT | Open source | Very permissive — do almost anything, just keep credit |
| Apache | Open source | Similar to MIT with patent protection |
| EULA | Closed source | End User License Agreement — restricts copying/modification |
| Freeware | Closed source | Free to use but source code not available |
| Shareware | Closed source | Free trial, then requires payment |
Open Source ≠ Free (as in no cost)
"Open source" means the code is publicly available — not necessarily that it costs nothing. Some open-source projects offer paid professional support (e.g., Red Hat Enterprise Linux). The term "free" in open source refers to freedom (to use, modify, share), not just price.
Worked Examples
1 Choosing Software for a School
Scenario: A school needs an office suite for 200 computers.
| Criteria | MS Office (Closed) | LibreOffice (Open) |
|---|---|---|
| Cost | ~$50 × 200 = $10,000/year | $0 |
| Compatibility | Native .docx/.xlsx | Good .docx support, occasional issues |
| Support | Microsoft help desk | Online community |
| Training | Widely known | Similar UI, minimal retraining |
Recommendation: LibreOffice saves $10,000+/year with minimal compromise for typical school use.
Common Pitfalls
"Open Source Is Less Secure"
This is a myth. Open-source projects like Linux are used in most servers worldwide precisely because the community can audit and fix security vulnerabilities quickly.
Tasks
Define open-source and closed-source software. Give two examples of each.
Explain why a government might choose open-source software over closed-source for sensitive systems.
Compare the GPL and MIT licenses. Which gives more freedom to the user? Which protects the open-source community more?
Self-Check Quiz
Q1: What makes software "open source"?
Q2: Is freeware the same as open source?
Q3: Which license requires derivative works to also be open source?