From IEEE Std 1003.1-2004 XBD 4.7 "File Times Update" [http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_07]: "st_ctime is associated with the times that the file status is changed."

This is clarified in the operations described throughout IEEE Std 1003.1-2004 XSH 3 "System Interfaces."

Although IEEE Std 1003.1-2004 only considers st_ctime as having second resolution, platform-specific extensions exist that provide st_ctime semantics but with sub-second resolution. Unix.ctime values from such platforms MAY use such finer-grain resolution.

From IEEE Std 1003.1-2004 XBD 4.7 "File Times Update" [http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#tag_04_07]: "The st_atime field is associated with the times that the file data is accessed."

This is clarified in the operations described throughout IEEE Std 1003.1-2004 XSH 3 "System Interfaces."

Although IEEE Std 1003.1-2004 only considers st_atime as having second resolution, platform-specific extensions exist that provide st_atime semantics but with sub-second resolution. Unix.atime values from such platforms MAY use such finer-grain resolution.

For performance reasons, some platforms allow operations to delay or suppress updates to st_atime. FTP servers on such platforms MAY refrain from publishing the Unix.atime fact.

File owner name, as mapped from the numeric owner ID, by the operating system.

File group name, as mapped from the numeric group ID, by the operating system.