Dumb Questions about CHDs

[WhereEaglesDare]

Okay so how does this thing work?  I got some CHDs for Street Fighter 3 and some other games.  I have read many articles about CHDs but I cant find one that says cut and dry how to use them.  Please in 10 words or less please tell me how to use CHDs.  Thank you.

[kronic24601]

you put the folder in with your roms. That's it.

(10 exactly)

[syph007]

put them in a new folder with the name of the rom ie  sfiiia  and put that folder in the roms folder of mame.

[WhereEaglesDare]

then what is a parent and how come some dont work or load at all?  I am getting them from a reliable source and I think they should work.  Am i doing something else wrong?

In fact I dont think they are even showingin the MAME Game listing.

Here is I did, I downloaded the RARs, unzipped them til I had the CHD file, sf3000.chd.  I created a folder inside the roms folder and name it sf3000 and then I put the folder.  I have several and I dont think any of them are working.  Is there a step I need to do to make MAME use them?

[syph007]

Very few work or run properly.  The only ones I've even tried are simpsons bowling and Area 51.

To use one as an example for area 51 I'd have the following in my roms folder.

[area51] folder with area51.chd inside
area51.zip rom

If you cant get any of the known ones that work to work, you must have a version mismatch or something.

Edit:

For the chd you are talking about, it would go in a folder named sfiii   and you should have a sfiii rom file as well.

[WhereEaglesDare]

Do you need to have a .zip rom in the root of the rom folder as well as the chd?  Is that called the Parent Rom?

[syph007]

Do you need to have a .zip rom in the root of the rom folder as well as the chd?  Is that called the Parent Rom?

Yes you need the rom files and chd files.

No a parent rom is something different.

[kronic24601]

1) You need compatible Roms that are built for the same MAME version.
2) SOME roms need CHDs
3) MOST games that use CHDs require ALOT of CPU power to run. For example, my 4.52GHz cpu barely runs Gauntlet Legends.
4) The Parent Rom holds all the ROM information, the US/JAP/etc version holds just "some" information to modify the game (usually disclaimers). You always need the parent rom, or at least the rom files.
5) BIOS, many (all?) of the roms use a separate BIOS file and will not run without it.
6) Tons of games have a preliminary or imperfect driver status, basically meaning they don't work.

Take a look at this site: http://maws.mameworld.info/maws/

If a game is not working. take a look on that site, it will tell you if it's a clone (meaning it needs a parent), needs a CHD, BIOS, if it works at all, etc...

Very useful site.

[Hoopz]

From the Mame FAQ:

LINK

[WhereEaglesDare]

Makes so much sense now!  I downloaded Judge Dredd (jdreddc) but jdreddc isnt showing up, because it looks for the jdredd rom then that rom references the jdreddc, does that sound right?