What is the difference between full, incremental, and differential backups?

What is the difference between full, incremental, and differential backups?

• A. Full backup copies all selected data; incremental backups copy only changes since the last backup of any type; differential backups copy changes since the last full backup.
• B. Full backups copy only new data; incremental backups copy all data; differential backups copy changes since the last backup.
• C. Full backups copy system files only; incremental backups copy user data; differential backups copy applications.
• D. Full backups copy changes since the last backup; incremental backups copy everything; differential backups copy nothing.

Answer: (A)

Backup strategies hinge on what data is captured and the reference point for changes. A full backup copies all selected data in one pass. An incremental backup copies only the data that has changed since the last backup of any type (full or incremental), so each incremental run adds only new changes. A differential backup copies all changes since the last full backup, so it grows with every differential until the next full backup. This setup explains restore behavior: with a full backup plus all incremental backups, you need the full plus every subsequent incremental to restore fully. With a full backup plus the latest differential, you only need the full and the most recent differential to restore. The other options mix up what each type copies or the reference point, so they don’t match how these backup methods actually operate.

Backup strategies hinge on what data is captured and the reference point for changes. A full backup copies all selected data in one pass. An incremental backup copies only the data that has changed since the last backup of any type (full or incremental), so each incremental run adds only new changes. A differential backup copies all changes since the last full backup, so it grows with every differential until the next full backup.

This setup explains restore behavior: with a full backup plus all incremental backups, you need the full plus every subsequent incremental to restore fully. With a full backup plus the latest differential, you only need the full and the most recent differential to restore. The other options mix up what each type copies or the reference point, so they don’t match how these backup methods actually operate.