I’m trying to run PS2 games on emulators like PCSX2 and AetherSX2, and they keep asking for a PS2 BIOS file. I understand it’s essential, but I’m not entirely sure why.

What exactly does the BIOS do, and why can’t emulators just run without it? Also, are there different versions of the PS2 BIOS depending on the console model or region? https://theps2bios.net/ps2-games/