MAME and Rollback question

[Red]

How does the Rollback work- Do I need the same exact set of roms and rollback set for it to work?  For example, I have the 0.123 set of roms, but the rollback set is 0.123u1, will that work to downgrade the roms to a lower version of MAME or do I need the rollback set to be 0.123 to match the rom set?

Also, if my rom set is 0.124u1, can I use the rollback set 0.123u1 or is it best to wait and get a 0.124 rollback set?

Do the CHD's get rolled back as well as the roms?  If not, how do you rollback the CHD's?

Thanks.

[u_rebelscum]

How does the Rollback work- Do I need the same exact set of roms and rollback set for it to work?  For example, I have the 0.123 set of roms, but the rollback set is 0.123u1, will that work to downgrade the roms to a lower version of MAME or do I need the rollback set to be 0.123 to match the rom set?

Also, if my rom set is 0.124u1, can I use the rollback set 0.123u1 or is it best to wait and get a 0.124 rollback set?

The roll back set contains all changes for the number it's called and back.  So the 0.123u1 file can be used on 0.123u1, 0.123, 0.97 and down.  If you use it on 0.124, the result will miss any files that were removed between 0.123u1 and 0.124.  So you might want to wait.  OTOH, if you aren't going to lay the games that the few roms that where removed, then go ahead.  If you do, the missing roms will show up after clrmamepro is finished.

Do the CHD's get rolled back as well as the roms?  If not, how do you rollback the CHD's?

No, and this question is boardline not allowed I don't know.

[Red]

Thanks u_rebelscum, much appreciated.

And I apologize if the question on the CHD's is not allowed.  I did a search before I posted that question and did not find anything, so I figured someone here might have some insight on it.  Thanks.