A normal backup (full backup) backs up every file on the specified volume or volumes (or partitions). In full backup system, the restore process requires only the most recent tape. A full backup needs a large storage space and requires more time for backup operation. If you have large amounts of data, running a daily full backup may not be practical because it may take too long to perform. Every file has an archive bit that flags whether or not the file needs to be backed up. When you change a file, this bit is flagged automatically, which means that the file needs to be backed up. In theory, any file that has been changed needs to backed up because we want to be sure we can always bring the file to its most recent state.
To view the archive bit in Windows 2003, right-click on the file and go to the properties. Once in the properties, click the Advanced button on the general tab. You will see the option that says “File is Ready for Archiving”. Whenever a new file is created or modified, Windows 2003 sets the archive bit. The important thing to understand when a full backup is performed is that the backup backs up all the files that you select (whether the archive bit is set or not), and then clears the archive bit so that the operating system and applications know that the file has been backed up.