Neo-geo.rom ng-sm1.rom ng-lo.rom ng-sfix.rom Having these 4 ROMs in every single NEO-GEO set means having a lot of redundant files, so it was decided to store them in a separated file, what would be called a BIOS file, and when running one of the NEO-GEO games, MAME will look for those ROMs in the BIOS file. This file is neogeo.zip In MAME 0.62, there are 6 BIOS files: cvs.zip, decocass.zip, neogeo.zip, pgm.zip, playch10.zip and skns.zip The problem with these type of files is that ClrMame Pro doesn’t update them so when after a scanning process we have some BIOS errors, we must correct them manually. The most common error arises when in a new MAME release is included a new BIOS file.