I would like to see a backup program that could be set to backup several different sets of data. to especially a CD-R or CD-RW
It does, but only to CD-RW.
How come no backup software I can find can write files out as a session to a CD-R, as opposed to a CD-RW?
ewen 
I guess they just expect people to want to be able to re-write their backups.
Hey Mike,
You can (sort of) “overwrite” to a CD-R, thereby re-saving your backups. Assume that you’ve got a file called xy.z and this file was written as a session to a CD-R. If the file attributes of the file change, this modified version of the file xy.z can be written again to the same CD-R (the process actually flags the original version as retired, writes the modified copy to the CD-R and writes out TOC pointing to the newer version).
The advantages to this method would be 1) lower media cost, 2) more robust media, 3) universal readability and 4)zero media preparation time.
The big thing here is the zero media preparation time. Like everyone else, making the time to take and verify backups is a necessary evil. I gave up on CD-RWs when I found that the CD-RW format time took longer than the backup did! I know, you only have to format them the first time (or on disk re-use), but you will always be stuck without a formatted disk when you can least afford the time.
Murphy’s Law will prevail.
The whole idea of backups is to make the process as unobtrusive as possible, with the highest degree of reliability, so the users can just focus on their work.
ewen 
Guys, since it exists a backup program why don’t move the discussion on the backpup forum https://forums.comodo.com/index.php/board,5.0.html
and making a request at the wishlist there?
https://forums.comodo.com/index.php/topic,130.0.html
This is the place for new programs 