Many arcade games were available in several slightly different forms. For example, Pac-Man was first released in Japan by Namco, and there it was named "Puck-Man." Midway then licenced and released it in the United States as "Pac-Man," and later re-released it with a slightly faster speed and different patterns. Variations of Pac-Man have also been found with different mazes, hearts instead of dots, and even piranha fish instead of monsters.
In MacMAME, a "parent" is usually the latest official version of an arcade game from its original company. "Clones" are variants of that game with slight differences from the original. Clones might be prototypes, bootlegs, regional versions for different countries, updated versions with bugs fixed, or simply the same game licensed to another company.
To list all of a game's clones in MacMAME, use the pulldown menu above the game list and select "Show Virtual Clones." Control-click on a game in the list to display (and jump to) its parent or clones.
MacMAME is clever about clones. If you have a parent ROM set (a zip file containing all the ROM files from the parent game) and you want to play a clone, then the clone's ROM set will only need to contain the ROM files unique to that clone (MacMAME will look in the parent ROM set for the ROM files which are identical to the parent's). This saves disk space on your computer, since identical ROM files aren't duplicated. Some web sites distribute clone ROM sets this way, containing only the ROM files which are different. The drawback of this approach is that you'll need a copy of the parent ROM files in order to play the clone, which is why many web sites distribute clones as complete sets so that they can be played without needing the parent set.
Another approach is to have one zip file which contains all the ROM files for the parent game and all of its clones. This is called a "merged ROM set", and if you're a completist who likes to have as many ROM sets as you can, it can be more convenient than having a separate file for each clone. Some web sites distribute ROM sets merged in this way. If you have merged ROM sets, select "Show Virtual Clones" from the pulldown menu above the game list in the MacMAME application's window so that MacMAME will show you what clones are available for it to use.
A problem can occur, however, when you have a parent ROM set which contains ROM files for that game's clones, and then you also have clone ROM sets which contain ROM files from the parent. This could happen if you obtain ROM files from several different sources, and the result is that you'll have several ROM files duplicated in the parent and clone sets and this will waste disk space on your computer. To solve this, you can merge the clone ROM files into the parent ROM set by hand. To help you, the "Analyze Romsets" button on the Reports tab will go through your ROMs folder and create a report showing all your ROM files, which parent or clone set they belong in, and whether you have any duplicates or damaged files.
Two useful programs for maintaining your collection of ROM sets are 'MacMAME Companion' (on Carlo Noben's site) and 'MacMAME Utilities.' If you have access to a Windows-based PC, a Windows utility named 'ClrMamePro' also does an extremely thorough job of sorting and cleaning up ROM sets.
A "ROM audit" is a report which will tell you whether any of the ROM sets you have are damaged or incomplete. To create this report, click the "Reports" tab in the MacMAME application window, then press the "Audit ROMs" button. Check "List problems only" and "Suppress warnings for known problems" (unless you want much more detailed information). Select "Ignore problems with CHD files" unless you want to check your copies of the compressed hard disk files (for some games which originally had built-in hard disks). Leave the "Audit Filter" blank, then press the "Audit" button. After a few moments, the report will appear, and then you can save it to a file on your computer if you desire.
The "Audit Filter" field lets you narrow your search. The asterisk is a wildcard. If you want to audit only the Pac-Man games, enter "pac*" in that field.
To have MacMAME list the clones which are available for you to play, select "Show Virtual Clones" from the pulldown menu above the game list in the MacMAME application window.
The "Mini Audit" lets you determine if the ROM files you have for a particular game are valid. Select the "Info" tab in the MacMAME application window, then select "Mini Audit" from the pulldown menu. If any of the ROM files are listed as anything other than "good," then you may need to obtain a new copy of that ROM set.
The picture to the right shows an audit of "Puzzle Bobble / Bust-A-Move" (pbobblen.zip) with several rom files missing. The missing files happen to be the Neo-Geo BIOS files; as described above under "What is a BIOS?", this could be fixed either by adding the missing files to the game zipfile or by putting them into "neogeo.zip".
The names of the rom files generally correspond to how the original rom chips are marked on the original arcade game motherboard.
The errors which can appear during a mini audit include:
- Not found: The rom file is missing; the game can not be played.
- Bad crc: The rom file is present, but it doesn't have the checksum which MacMAME expects. Most likely you need to get a newer copy of this game's roms to work with this version of MacMAME.
- Bad length: The rom file is present, but it has the wrong size, so it might not be valid.
- No good dump exists: The original rom chip has never properly been copied to a file. The file you have may be partially or entirely bad. The game may or may not be playable.
- No dump exists: The original rom chip has never been copied to a file. It is possible that the original game motherboard has never been found intact.
Errors listed in red will prevent the game from being emulated at all. Errors listed in yellow will allow you to try emulating the game, but it might not be playable.