Open source and closed source

Overview

Recall questions on open source and closed source software, the arguments for and drawbacks of each, whether open source means free, how companies profit from open source, security arguments, and choosing between them for a scenario.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is open source software?

   Model answer

   Software released with its source code, under a licence that allows anyone to read it, modify it and redistribute it. It is usually, though not necessarily, free of charge; the defining feature is the freedom granted by the licence, not the price.

2. 2

   What is closed source software?

   Model answer

   Software distributed only as compiled machine code, with the source code kept secret by the owner. The licence restricts what the user may do: typically the user may run it but may not modify it, copy it beyond agreed limits, redistribute it, or attempt to reverse-engineer it.

3. 3

   Give three arguments in favour of open source software.

   Model answer

   It is usually free to obtain, so there are no licence fees and it can be deployed on as many machines as needed. It can be modified to fit exactly what an organisation needs, and that adapted version can be shared. A large community can inspect the code, so bugs and security flaws are often found and fixed quickly and there are no hidden functions. It also removes dependence on one supplier, so the software cannot be discontinued or made unaffordable at the vendor's choice, and open file formats make future migration easier.

4. 4

   Give three arguments in favour of closed source software.

   Model answer

   It usually comes with guaranteed professional support, warranties and someone contractually responsible when it goes wrong. It is generally thoroughly tested and polished before release, with proper documentation and training material, because the company's income depends on it. Development is funded and directed, so features and updates arrive on a predictable schedule. It is also often better supported by hardware manufacturers and is the format other organisations expect, and the owner keeps control of the intellectual property they invested in.

5. 5

   Give two drawbacks of open source software.

   Model answer

   Support may be limited to community forums with no guaranteed response and nobody accountable if a problem is not solved, so an organisation may have to employ its own expertise or pay a third party. Quality and documentation vary enormously between projects, and a project maintained by volunteers can be abandoned. Compatibility with widely used closed formats and with some hardware can also be poorer, and staff may need retraining.

6. 6

   Give two drawbacks of closed source software.

   Model answer

   Licence costs can be substantial and recurring, and grow with the number of users. The user cannot modify it, so if it does not quite do what is needed they must wait and hope the vendor agrees to change it, and they cannot inspect the code to verify what it does with their data. There is also vendor lock-in: proprietary file formats and the risk that the product is discontinued, its price raised, or support for an old version withdrawn, leaving the organisation with no route out.

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