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Each backup set is grouped by similar backup types. This means that a single set will only consist of images of *exactly the same partitions or a File and Folder backups of exactly the same selection criteria.
*Note: A change in partition layout will cause a new backup set to be created even if the drive letters are consistent. The partitions must have the same disk offset and length and must be from the same disk, i.e, the disk must have the same Disk ID.
e.g, If you run an Incremental image of only drive 'C' and the target folder contains 4 image files:
6698CD700DF88DF4-00-00.mrimg?? Drives Drives: C, D, E?? Created Created 1st Jan 2013
430D57E2CEEA8552-00-00.mrimg?? Drive:?? F?????????? Created? Drive: F Created 2st Dec 2012
1EB1112ABA7C3898-00-00.mrimg?? Drive:?? C:????????? Created? Drive: C: Created 1st Nov 2012
D407A9E1BF98D822-00-00.mrimg?? mrimg Drive:?? C:????????? Created Created 1st Oct 2012
Then the newly created image file will be 1EB1112ABA7C3898-01-01.mrimg. ? This is because file 1EB1112ABA7C3898-00-00.mrimg is the most recent full image in the target folder that contains exactly the same partitions as the current Incremental image. The next Incremental (or Differential) image would be 1EB1112ABA7C3898-02-02.mrimg and so on...
Note: If there was no existing backup set that contained only drive 'C:' then a new backup set (full) would be created.
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Doesn't this get confusing if multiple backup types are saved to the same folder?
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A differential backup saves only the changes made since the last full backup of the same type found in the target folder for the backup.
An incremental backup saves only the changes made since the last backup of the same type found in the target folder for the backup.