[RockerC]

I guess those cores will need special treatment and some additional effort. Didn't try any of them, but that's how I think about it.

You got it, yes that is what I thought too, that libretro cores for those multi-platform emulators engines will not work the same as a libretro core that only support one (1) single platform.

I think if the filetype is supported by several emulators you have installed on your system, you still have the option to choose one. I think it decides one emulator as a top priority but you can still, from the context menu, select "play with..." and have a list with all the available emulators for that particular filetype.

Yes but I mean is multi-platform supporting emulators like MESS and UME can't always auto-detect what platform the ROM is for, so it need to be provided with argument parameters.

MESS is a single libretro core that support emulating hundreds of different consoles/computer platforms in a single binary, (read http://en.wikipedia.org/wiki/Multi_Emula...per_System ).

The game ROM could be for Amstrad CPC or Commondore 64 and a multi-platform emulator engine like MESS could run both those just fine, but only it you pass it the right arguments.

Again please see http://www.libretro.com/index.php/mamemessume-cores/

MESS/UME support

MESS and UME have been options for a while now, but they weren’t really easy to use. First of all some clarifications.

First of all, these cores work by passing arguments like you would pass on a CLI for their standalone counterparts. Loading from RGUI imposes some limitations on that regard so some assumptions are being made for you.

Second, since the 0.138 release there support for an XML format that documents the software released for the many supported systems. These are stored in the hash directory and you can obtain them from the standalone releases.

Besides being a documentation resouce, softlists allow to load software by just specifying the system and the rom name. For example on standalone mess you could do:

mess -rompath roms nes smb

With full path loading you would do:

mess -rompath roms nes roms\nes\smb.zip

The benefits are considerable when you consider that games might have more than one file, for instance multi floppy X68000 games, those would be impossible to load from RGUI without using softlists.

The downsinde, softlist roms are not the same as the ones you might already have so full path loading still works but only with simple one file based images.

....

For full article please see http://www.libretro.com/index.php/mamemessume-cores/