Emulators and different bios/regions

Can anyone explain why Saturn emulators require specific bios regions to work with different region discs? I put a region switch in my original Saturn back in like, 1995 - which plays both US and Japanese discs on the original US bios without any issues. It still works to this day, I'd open it and take pictures to remember what I did, but if it ain't broke - don't fix it!

I only recently started messing with Saturn emulation (mostly because I'm still waiting for an ODE so I can hack stuff on real hardware), and found this quite curious. Obviously, it's easy to find the bios files out there, but it's interesting that this isn't required on real hardware at all, only a couple jumpers need switched.
Simply, to avoid potential compatibility issues.
There are chances to freeze the game when switching between different versions(not only different regions) of bios, e.g. if you save a game with one bios, then load the game save with another bios.
There are more differences between EU and JP versions of bios than US and JP ones. So if you switch between PAL and NTSC bios, the risk is increased.
Makes sense. I don't own any PAL games, so I never would have experienced that. I probably would have never tried swapping regions between saves, but that's really only possible with emulation. Still, I was curious. Would be nice to add a switch to skip the region check though.
Nova has no such restrict currently, but I will add the restrict in future versions like other emulators.
And I will add a switch like you suggested.
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Established Member
There is a hacked region free bios to use with ssf. Yaba-sanshiro I think has a auto-region patch, don't know about mednafen.
right, but my point was - on real hardware - the bios region doesn't actually matter. it's the position of the jumpers on the mainboard. :)