Suppose you want to run a full backup of a group of files at the beginning of a week, and then back up only the files that have changed on the remaining days of the week. To do so, you have the choice of Incremental or Differential backups.
There are also several types of backup routines available. The most common are full, copy, differential, incremental, and daily.
A full backup backs up each file and turns a setting (also called a switch) on the file to mark it as backed up. Think of a switch as a light switch, when a file is created the switch is in the off position. When the file is backed up the light (file in our case) is turned on. When you edit the file and save it the switch is set back to the off position just like when you leave the room and turn off the light. When a file or group of files are copied they are duplicated elsewhere but the setting (switch) is not changed.
An incremental backup only backs up the files that have been added or changed since the last backup and turns the switch on. It does this by looking for switches that are off.
A differential backup copies only the files that have been added or changed since the last backup but leaves the switch off.
The daily backup only backs up files that were created or modified that day.
