Archive bit
(重定向自Archive attribute)
The archive bit is a file attribute used by Microsoft operating systems, by OS/2 and by AmigaOS. Typically its state indicates whether or not the file has been backed up.
On Windows and OS/2, when a file is created or modified, the archive bit is set, and when the file has been backed up, the archive bit is cleared. It is by use of the archive bit that incremental backups are implemented.