I am setting up Sega Cd I have many questions What core is recommended? Is a Sega Bios file or Multiple Bios Files required? Where does, if needed, The bios file(s) go…into what directory in Retro Arch? Is there any special setting or configuaration need when setting up the core?
Either Genesis Plus GX or Picodrive. Their documentation pages are here: https://docs.libretro.com/library/genesis_plus_gx/ and here https://docs.libretro.com/library/picodrive/
BIOS files go into the ‘system’ directory. If you don’t know where that is, go to settings > directory and see what directory it’s pointing to.
Thank you very much for your reply Hunter. I tell you there is nothing like it then spending a Sunday afternoon configuring a new game console, For your game cabinet many thanks
It’s worth noting that PicoDrive is the only one out of those 2 cores that emulates 32X.
The reason I bring that up is because if you plan on doing any of the 32X enhanced CD games, you won’t be able to with GenesisPlusGX.
There’s only 6 of them, and they are all FMV titles, so it may not be an issue. It’s something I ran into doing my own setup though.
Pico Drive works pretty well on all sorts of devices and emulates 32x CD games as well 
Thank you all for replying. Your help is greatly appreciated!!!