Storing differential imagaes on optical media

[chrizio]

I keep my images also on RAM-DVD media.
All because bad experiences with hard disk.
So, I have three media. One for complete image #1,
two for differentials #2 and #3.
Full image is created once two months and burned to #1.
Once a week a differential backup is made. And stored
alternately on #2 and #3.
Actually, I realized following:
while creating a differential and burning it to optical media (#2 or #3)
I have also to burn again the full image to media #1. Is that right ?

Cause creation of differential one leads to some update
of associated full image. However, one can't see it,
cause modification date of full image file stays untouched.

[seekforever]

A differential backup is based on the Full backup that is referenced when the differential is made. So if you have a copy of the Full on DVD already you don't need to burn it again. Of course, if you make a new Full then you have to burn it.

Creating differentials or incrementals do not modify the Full image. It is never altered.

[chrizio]

Thanks for your informative answer.
I see, my assumption was incorrect.

It is enough to copy to media the backup just made only.
The file containing full image is not modified on any manner
while creating diffs/incs.