Datasheet

1058
Do Not Forget about Data Protection
Backup review
You can find out more about backups in Book VII, Chapter 3, but for the
exam, here are some of the key points you need to remember.
When you perform a backup, the OS keeps track of which files have been
changed since the last backup by setting the archive bit. The archive bit
is an attribute of the file that tells the system that the file has changed. To
view the archive bit within Windows XP or Vista, right-click the file and
choose Properties. In the Properties dialog box, click the Advanced button.
The first option in the Advanced Attributes dialog box that appears — File Is
Ready for Archiving — is the archive bit. (See Figure 1-10.) When this check
box is selected, it means that the file needs to be backed up because it has
changed.
Figure 1-10:
Viewing the
archive bit
in Windows.
Before you perform a backup, decide what type of backup to perform. Each
backup type deals with the archive bit a little differently. Here are the three
major types of backup:
✦ Full backup: Copies any files that you select, whether the archive bit
is set or not, and clears the archive bit on any file that is backed up —
essentially recording the fact that the file has been backed up.
✦ Differential backup: Copies any files that have changed, but it does not
clear the archive bit; thus, there is no record that the files have been
backed up. The benefit is that the next time you do the backup, the files
will be backed up again because the archive bit has not been cleared. As
far as the OS is concerned, the file has not been backed up since it was
changed.
✦ Incremental: Copies any file that has changed and then clears the
archive bit on any files that are backed up. Thus, if a file is copied
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