This is where most users give up. Let’s break the bank of jargon.
MAME ROMs are stored in .zip archives. The files inside are not "the game"; they are individual chips (Program ROMs, Sound ROMs, Graphics ROMs). To save hard drive space, the MAME community created three distribution standards. mame 2003-plus reference: full non-merged romsets
MAME 2003-Plus was designed for simplicity and low overhead. It does not want to "hunt" for parent ROMs or BIOS files across a messy folder structure. It wants to look inside one ZIP file, find everything it needs, and launch the game. This is where most users give up
Here is where the magic happens:
Using clrmamepro with the MAME 2003-Plus .dat: The files inside are not "the game"; they
You cannot ask where to download ROMs (Rule #1 of retro communities), but you can learn how to build them legally if you dump your own arcade boards, or how to audit the sets you find online.
Verdict: For MAME 2003-Plus on a handheld or retro box, Full Non-Merged is the only logical choice. You don't want to be Wi-Fi tethering to download a parent ROM just to play a clone at an airport.