An incremental backup process
A.
Backs up all the files that have changed since the last full or incremental backup and sets the archive bit to
0.
B.
Backs up the files that been modified since the last full backup. It does not change the archive bit value.
C.
Backs up all the data and changes the archive bit to 0.
D.
Backs up all the data and changes the archive bit to 1.
Explanation:
The incremental backup method backs up all the files that have changed since the last full or incremental
backup and resets the archive bit to 0. This is known as “clearing the archive bit”. A full backup backs up all
files regardless of whether the archive bit is 1 or 0 and sets the archive bit to 0.
The archive bit is used by the backup process to determine whether a file has been changed. When you modify
a file or create a new file, the archive bit is set to 1. This tells the backups process that the file has changed (or
is a new file) and needs to be backed up. When an incremental backup backs up the file, it sets the archive bit
to 0. When the next incremental backup runs and sees that the archive bit is 0, the incremental backup knows
that the file has not changed since the last backup and so will not back up the file again.
Incorrect Answers:
B: This answer describes the differential backup process. The differential backup does not change the archivebit value; an incremental backup does change the archive bit value to 0.
C: This answer describes the full backup process. An incremental backup does not back up ALL files; it only
backs up changed files.
D: An incremental backup does not back up ALL files; it only backs up changed files. Furthermore, it changes
the archive bit value to 0, not 1.Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, pp. 801-802