3. 一般的なオプション

一般的なオプションは、大抵の場合、設定の必要はありません。また、 これらを利用することで、柔軟性を高めたり、セキュリティを上げる ことができます。

• 読み込み専用 書き込みからパーティションを保護することができます。管 理者権限でさえも、そこへ書き込むことが不可能になります。 これは通常のハードドライブ・パーティションではまずほと んど利用されません。
• ユーザ権限でのマウント操作の許可 このオプションは一般的に以下の次のこと許可します。これ は取り外し可能なメディアに対して役に立ちます。 このオプションを指定すると、誰でもいつでも接続を成立さ せることを許可します。普通は、root(管理者)のみがマウン トを確立させることができます。
• 起動時にマウントしない とりわけ取り外し可能なメディアで便利でしょう。システム がブート時にマウントを成立させようとするのを防ぎます。
• プログラムの実行を許可しない It is a security feature, especially useful for removable media. If you set the user mountable option on a removable media, it allows any user to come and install a set of files specially setup to give him full access to your system (administrator privilege). This option would prevent this from occurring.
• 特殊デバイスファイルをサポートしない This is a security feature. Special devices are generally created with proper access rights in the /dev directory. They may be created in other place too with the mknod command. This feature prevents mounting a media with special device created with relaxed security. Such devices would defeat all security on the system.
• ユーザ権限が設定されている(SetUID)プログラムを許可しない Again a security feature. It is a compromise between full access and the above option (No execution allowed). By setting this option, the system will deny privileged programs their special rights. A privileged program is one that switches the user to another identity while it is running (generally root). This allows the user to do special tasks only the supervisor can do.
• ユーザによるディスク使用量を制限する This flag tells the kernel to enable quota accounting on the file system. Quota accounting maintains for each user in real time the amount of disk space used and the amount of files and directories they own. Limits may be imposed on some or all users. This is controlled separately for each file system. The file quota.user is created in the root of the file system (Linuxconf will create it for you if you activate this feature). The utility quotacheck is run to initialize the file with the current state of the file system. The kernel from now on will silently update this per user account. This is useful to prevent a single user from filling the disk.
• グループによるディスク使用量を制限する This is the same feature as user quota enabled, but for groups. The group quotas hold the sum of the quotas of all file members of the group. A file quota.group is created when this feature is enabled and the utility quotacheck is used to initialize the file. While a user may be under his personal quota limit, the quota of his group may be over its limit. The user will be prevented from creating new files and/or growing them.