問55
頻出度★☆☆
オープンソースソフトウェアに関する記述として, 適切なものはどれか。
平成21年度 春期 ITパスポート試験 問55
テクノロジ系ソフトウェア › オープンソースソフトウェア
This question's explanation and your answers so far.
解説
問 55
Incorrectア
This describes shareware. Shareware can be used free of charge for a certain trial period and requires payment for continued use, and its source code is normally not published. The essence of OSS is that modification and redistribution are already permitted at the moment you obtain it, which has nothing to do with whether there is a trial period or how it is charged for.
- イ
正解 The correct answer is イ. Open source software (OSS) is software whose source code is published and which anyone is allowed by its license to obtain, use, modify, and redistribute. The Open Source Definition (OSD), which sets out the requirements for OSS, likewise makes it mandatory that the source code be available and that the creation of derived works (modified versions) and their distribution under the same license be permitted. Therefore choice イ, “The publicly available source code may be modified and improved after it is obtained”, correctly states the very nature of OSS. Note as well that although improvement is free, many OSS licenses attach conditions when a modified version is distributed, such as keeping the copyright notice, including the license text, and inheriting the same license.
Incorrectウ
Software whose copyright has been waived is in the public domain, which is not OSS. In OSS the author retains the copyright and then, through a license (GPL, Apache License, MIT License, and so on), grants users the conditions for use, modification, and redistribution. It is precisely because the copyright is retained that the license conditions can be enforced.
Incorrectエ
Paid support services are available for OSS as well. Even though the software itself can be obtained free of charge, many vendors sell deployment support, troubleshooting, and maintenance for a fee, and paid support contracts for Linux distributions are a typical example. The definition of OSS concerns publication of the source code and the freedom to modify and redistribute it; it does not prohibit selling support for a fee.
ここがポイント
- The core requirements of OSS are three: the source code can be obtained, it may be modified, and it may be redistributed. Being free of charge or waiving copyright is not a requirement; the author keeps the copyright and sets the conditions of use through a license.
- Distinguish OSS from distribution forms that are easily confused with it: shareware is charged for after a trial period; freeware is free of charge but its source code is often not published; public domain means the copyright has expired or been waived; OSS means the copyright is retained while the source code is published and modification and redistribution are permitted. In addition, a paid support business built around OSS is perfectly viable.
用語