問74
頻出度★☆☆
階層型ディレクトリ構造のファイルシステムに関する用語と説明 a～d の組合せとして, 適切なものはどれか。 a 階層の最上位にあるディレクトリを意味する。 b 階層の最上位のディレクトリを基点として, 目的のファイルやディレクトリまで, 全ての経路をディレクトリ構造に従って示す。 c 現在作業を行っているディレクトリを意味する。 d 現在作業を行っているディレクトリを基点として, 目的のファイルやディレクトリまで, 全ての経路をディレクトリ構造に従って示す。
平成23年度 秋期 ITパスポート試験 問74
テクノロジ系ソフトウェア › ファイルシステム
This question's explanation and your answers so far.
解説
問 74
Incorrectア
Although absolute path = b is correct, current directory = a and root directory = c have a and c swapped. Because a means “the directory at the very top of the hierarchy”, it is the description of the root directory, and it cannot be the description of the current directory, which points to the directory being worked in right now. Conversely, because c means “the directory in which work is currently being performed”, it is the description of the current directory, and it cannot be the description of the root directory, which exists only once at the very top.
Incorrectイ
All three are wrong. On top of swapping a and c just as ア does, setting absolute path = d is also wrong. d shows the path starting from the current directory, which is the description of a relative path. An absolute path always starts from the root directory, so it has the property that its notation does not change even when the working location changes. This option gets wrong the most basic point of all: that absolute and relative paths are distinguished by where the starting point is.
- ウ
正解 In a hierarchical directory structure, the one and only directory at the top of the tree is called the “root directory”, and directories and files branch out below it. Therefore a, which means the directory at the very top of the hierarchy, is the root directory. On the other hand, the directory in which the user is working right now is called the “current directory”, and c, which means the directory in which work is currently being performed, corresponds to it. The remaining b and d are both ways of expressing the path to a target file or directory; the only difference is where the starting point is. If the starting point is the root directory, the notation does not change no matter which directory you are working in, giving a unique path, and this is called an “absolute path”. If the starting point is the current directory, the notation changes depending on where you are working, and it becomes a “relative path”. Since b starts from the directory at the very top of the hierarchy it is an absolute path, and since d starts from the current directory it is a relative path. Putting this together, current directory = c, absolute path = b, root directory = a, so ウ, which shows this combination, is the correct answer.
Incorrectエ
The correspondences current directory = c and root directory = a are correct, but absolute path = d is wrong. d is the way of showing a path starting from the directory in which work is currently being performed, that is, from the current directory, so it is the description of a relative path, and it has been mixed up with b, which is the description of an absolute path. In the correct combination b is what corresponds to the absolute path, so this option is wrong in only one place, making it a typical trap choice.
ここがポイント
- Basic terms of the hierarchical directory structure. The root directory is the single directory that exists only once at the very top of the hierarchy, and the current directory refers to the directory in which work is currently being performed.
- The two kinds of paths are distinguished by their starting point. Showing the entire path starting from the root directory is an absolute path (unique regardless of the working location), while starting from the current directory gives a relative path (its notation changes depending on the working location).
用語