While mark is correct on all counts
If you want to do a 'clean' set you will need a rom manager like
clrmamepro I make my roms as
non-merged and then create my list and filter it using a spreadsheet pick the roms I want and then build a script to delete the rest. it is overkill and take some work.and some learning..but with hard drives being so much larger these days it may not matter
However you may want to remember that most people do not remember "Puckman" but they
do remember "Pac-Man" (i.e. puckman is the parent and is
needed to run pacman...this goes for galaga3 and some others..
Also there are roms in a mame set are are marked as
not working in mame..no need to have them take up space on the drive either...but like I said above
mame dats for clrmamepro
here..youtube video to use clrmame pro
herefun fact: A full
working arcade set of roms and chds can fit on a 40..(50?) gig hard drive