Which of the following is an open source software ?
2015
Which of the following is an open source software ?
Answer: C. Mozilla Firefox — CONCEPTOpen-source software is software whose source code is published under a licence that allows anyone to read it, modify it and redistribute it.…
- A.
MS Word
- B.
Windows
- C.
Mozilla Firefox
- D.
Acrobat Reader
Show answer & explanation
Correct answer: C
CONCEPT
Open-source software is software whose source code is published under a licence that allows anyone to read it, modify it and redistribute it. Proprietary (closed-source) software is licensed only as a ready-to-run program: the vendor keeps the source code and the licence forbids modifying, decompiling or redistributing it. Whether a product is open source is therefore decided by the licence attached to its source code, not by its price and not by the kind of program it is.
APPLICATION
Apply that licensing test to each of the four named products:
Software | Publisher | Source code |
|---|---|---|
MS Word | Microsoft | Kept closed under the Microsoft Software Licence Terms |
Windows | Microsoft | Kept closed under the Microsoft Software Licence Terms |
Mozilla Firefox | Mozilla | Published in full under the Mozilla Public License |
Acrobat Reader | Adobe | Kept closed under the Adobe end-user licence agreement |
Mozilla publishes the complete source code of Firefox under the Mozilla Public License, so anyone may study the browser, change it and redistribute their changed version. Mozilla Firefox is therefore the open-source software in this set.
CROSS-CHECK
MS Word and Windows are supplied to users as compiled programs under Microsoft's licence terms, which grant a right to run the software but never release its source code.
Acrobat Reader can be downloaded at no cost, yet Adobe's end-user licence agreement expressly bars modifying, decompiling or redistributing it — so a zero price does not make a program open source.
The deciding property is always the source-code licence. Free-of-charge (freeware) and open source are different ideas: freeware only removes the price, while open source removes the restriction on reading and changing the code.