A-Level Computer Science / Unit 7: Responsible and Legal Computing

7.1.3 Choosing a Software Licence

🔒 Lesson slides are available to signed-in users. Sign in

7.1.3 Choosing a Software Licence

Copyright identifies who controls a program, while a software licence states what users are allowed to do with it. A licence may limit the number of users, permit or forbid modification, control redistribution, require payment, or place conditions on modified versions.

This section compares the licensing approaches named in the syllabus: commercial software, shareware, free software associated with the Free Software Foundation (FSF), and open-source software associated with the Open Source Initiative (OSI). Freeware is included only as a useful comparison because its name is often confused with free software.

By the end of this section, you should be able to:

  • Explain how a software licence differs from ownership of the software.
  • Compare commercial software, shareware, free software and open-source software.
  • Describe the roles of the Free Software Foundation and the Open Source Initiative.
  • Distinguish price, source-code access, modification rights and redistribution rights.
  • Select and justify a suitable licensing approach for a given situation.
Software licence: a set of legal terms that grants specified rights to use software and states any conditions or restrictions attached to those rights.

What Does a Software Licence Control?

A licence should be examined by looking at the permissions it grants, not simply at whether the software has a price. Two programs that are both free to download may give users very different rights.

Question to ask Why it matters
Who may run the software? The licence may restrict use to one person, one device, one organisation or a particular purpose.
Is the source code available? Without source code, users cannot realistically study or alter how the program works.
May the program be modified? An organisation may need to adapt the software to its own hardware, language or workflow.
May copies be redistributed? The licence determines whether original or modified copies can be shared with other people.
What conditions apply? Conditions may include payment, attribution, keeping notices, publishing source code or using the same licence.
What support is provided? Updates, training, technical support and service guarantees may affect the practical choice.
Common mistake: Price and freedom are different. Software can cost nothing but still forbid modification, while software that grants extensive freedoms may legally be sold.

Commercial and Proprietary Licensing

In syllabus questions, commercial software normally refers to proprietary software supplied by a vendor as a product or paid service. The vendor keeps control of the program and grants customers limited rights through a licence. The source code is normally unavailable to the customer.

A commercial licence might be based on named users, devices, simultaneous users, a whole organisation or a subscription period. The exact arrangement depends on the vendor's terms.

Arrangement Possible situation Important limitation to check
Single-user or named-user licence A designer needs access to a specialist modelling package. Whether the same account may be used on more than one device.
Device licence A program is installed on fixed workstations in a media room. Whether moving the software to replacement hardware is allowed.
Site or organisation licence A college needs the same application across several classrooms. The maximum number of users, installations or simultaneous sessions.
Subscription licence A company pays monthly for access, updates and cloud services. What happens to access and stored data when the subscription ends.

Commercial software can be a sensible choice when an organisation needs a finished product, compatibility with existing systems, accountable technical support, regular security updates or staff training. Possible disadvantages include recurring cost, restrictions on copying, dependence on the vendor and little ability to inspect or customise the code.

Exam tip: Do not justify commercial software only by saying “it is better”. Link the choice to a requirement such as specialist support, compatibility, rapid deployment or a service agreement.

Shareware: Try Before Committing

Shareware is proprietary software distributed so that potential customers can try it before purchasing or registering the full product. The trial may end after a set period, restrict particular features, limit the amount of data processed or display reminders to pay.

Shareware: proprietary software offered for trial or evaluation, usually with limits on time, features or continued use.

Shareware can reduce purchasing risk because users can test whether the program meets their needs. However, trial access does not normally include the source code or permission to modify and redistribute the software.

Common mistake: Shareware is not necessarily a permanently free or incomplete program. Some trials provide the full feature set for a limited time; others restrict features. The licence terms must be checked.

Free Software and the Free Software Foundation

The Free Software Foundation (FSF) focuses on the freedoms granted to users. Here, the word free refers to liberty rather than price. A program can therefore be free software even when someone charges for distributing, supporting or packaging it.

A free-software licence is designed to give users four broad freedoms:

Freedom Meaning for the user
Run Run the program for any purpose without needing separate permission for that purpose.
Study Examine how the program works; access to the source code is required.
Share Redistribute copies of the original program.
Improve Modify the program and distribute modified versions; source-code access is required.
Copyleft: a licensing method that uses copyright to preserve specified freedoms when covered software or modified versions are redistributed.

Some free-software licences use copyleft and require redistributed modified versions to remain under compatible freedom-preserving terms. Other free-software licences are permissive and do not impose the same requirement. Therefore, free software does not automatically mean copyleft software.

Open Source and the Open Source Initiative

The Open Source Initiative (OSI) maintains the Open Source Definition and reviews licences submitted for approval. An open-source licence does more than make code visible: it must grant rights that allow software to be used, modified and redistributed under the licence conditions.

Open-source software: software released under a licence that provides access to source code and permits use, modification and redistribution under stated terms.

Open-source development can support collaboration, independent security inspection, localisation and adaptation to new hardware. However, the existence of source code does not guarantee that a project will be easy to maintain, secure, well documented or supported.

Common mistake: “Source available” is not always the same as open source. A developer may let people read code while still forbidding modification or redistribution. The licence permissions determine whether it is open source.

Comparing the Required Licensing Approaches

Approach Typical source-code access Modification and redistribution Typical reason to choose it
Commercial proprietary software Not normally provided Restricted by the vendor's licence A ready-to-use product, vendor support or compatibility is required.
Shareware Not normally provided Modification and redistribution are usually restricted The user wants to evaluate a proprietary product before buying it.
Free software associated with the FSF Required for studying and modifying Users receive freedoms to run, study, share and improve, subject to licence terms User freedom, long-term control or community improvement is important.
Open source associated with the OSI Required Use, modification and redistribution are allowed under an approved licence Collaboration, inspection, adaptation or reduced vendor dependence is important.

Where Does Freeware Fit?

Freeware commonly means proprietary software supplied at no monetary cost. It usually provides neither source code nor broad modification rights. It is useful for distinguishing zero price from the freedoms associated with free software, but it is not one of the main licensing categories named in this syllabus section.

Exam tip: When comparing licences, organise the answer around four dimensions: price → source code → modification → redistribution. Add support or compatibility when the scenario makes these relevant.

How to Choose and Justify a Licence

A strong recommendation begins with the organisation's needs. It then connects those needs to the permissions, restrictions and practical support offered by the licence.

Decision step Question How it improves the justification
1. Identify requirements How many users? Is customisation needed? Is support essential? Prevents a vague recommendation based only on price.
2. Match licence features Does the licence allow the required use, modification and distribution? Shows why the licence is legally and technically suitable.
3. Consider trade-offs What cost, restriction, maintenance burden or vendor dependence remains? Creates a balanced answer rather than an unsupported claim.
4. Reach a judgement Which option best meets the most important requirements? Produces a clear, scenario-specific conclusion.

Worked Example: Environmental Sensor Network

A community science group wants software for 60 low-cost air-quality sensors. Volunteers must adapt the code to different sensor boards, and partner schools should be able to share improvements. The group has limited funds but has several experienced programmers.

Requirement Licence implication
Adapt the program for different hardware Source code and permission to modify are essential.
Allow schools to exchange improvements Redistribution of original and modified versions must be permitted.
Keep purchase costs low A licence with no per-device fee would be helpful.
Programmers are available internally The group may be able to manage maintenance without a proprietary support contract.

Reasoned choice: an appropriate free or open-source licence would fit the main requirements because it can permit inspection, modification and redistribution. A copyleft licence may be preferred if the group wants redistributed improvements to remain available under similar terms. A permissive open-source licence may be preferred if the group is willing to allow modified versions to be incorporated into products under different terms.

Model structure: “Choose ___ because the organisation needs ___. This licence permits ___. A possible drawback is ___, but it is less important here because ___.”

Interactive: Software Licence Chooser

Select a scenario and compare the licence families. Use the recommendation as a starting point, then add your own justification using source-code access, modification rights, redistribution, cost and support.

Choose a scenario

Suggested focus

School computer lab

Compare a commercial site or educational licence with an open-source alternative. The school should consider user numbers, support, compatibility and total cost.

Commercial Typical financial cost
Typical modification freedom
Usually proprietary; vendor terms control installation and use.
Shareware Typical initial cost
Typical modification freedom
Evaluation access; continued or full use may require payment.
Freeware Typical financial cost
Typical modification freedom
Usually no-cost proprietary software; source code is normally unavailable.
Free / Open Source Typical acquisition cost
Modification freedom
Source code and broad permissions are provided, but licence conditions still apply.
Widget reminder: The meters show broad tendencies, not rules that apply to every product. Always read the actual licence before making a real legal or purchasing decision.

Common Mistakes and Misconceptions

  • Assuming payment transfers ownership of the program. A customer usually receives permission to use it.
  • Comparing licences only by cost and ignoring source code, modification and redistribution.
  • Using freeware and free software as if they mean the same thing.
  • Claiming that visible source code automatically makes software open source.
  • Describing the FSF or OSI as a single licence. They are organisations associated with definitions and approved or recommended licences.
  • Assuming every free-software licence uses copyleft.
  • Recommending open source only because it may be cheaper, without considering maintenance skills and support.
  • Recommending commercial software without linking vendor services to the scenario.

Practice

Core questions

  1. Explain the difference between owning software copyright and holding a licence to use the software.
  2. State three permissions or restrictions that a software licence may control.
  3. Explain why shareware may help a user make a purchasing decision.
  4. Describe the main idea behind free software associated with the FSF.
  5. Explain why source-code visibility alone is not sufficient for software to be open source.
  6. Explain the difference between free software and freeware.
  7. Describe what a copyleft condition aims to preserve when modified software is redistributed.

Licence-selection scenarios

  1. A hospital needs a mature records package that integrates with existing equipment and includes guaranteed technical support. Recommend a licensing approach and justify it.
  2. A robotics club needs to change control software for several experimental robots and publish its improvements for other clubs. Recommend a licensing approach and justify it.
  3. A photographer wants to test an editing package during one project before deciding whether to subscribe. Explain why shareware or a trial licence may be appropriate.
  4. A small charity is considering a no-cost open-source database. Explain two benefits and two practical issues it should consider before choosing it.
Extended-answer tip: A justified choice should contain a recommendation, a matched licence feature, a consequence for the organisation and at least one trade-off.

Review

Prompt Strong answer should include
Software licence Permission to use software under stated rights, conditions and restrictions.
Commercial proprietary software Vendor-controlled use, normally closed source, often chosen for a finished product and support.
Shareware Proprietary software distributed for evaluation, often limited by time or features.
Free software / FSF Freedom to run, study, share and improve; source access is needed for study and modification.
Open source / OSI A licence meeting open-source criteria, including source access and rights to use, modify and redistribute.
Copyleft A method that preserves specified freedoms when covered versions are redistributed.
Good justification Scenario requirement → matching licence feature → effect → trade-off → conclusion.
Final exam tip: The verb justify requires more than naming a licence. Explain why its permissions and restrictions fit the stated situation better than the alternatives.