Hi, I have been placing all my BIOS ROMs in the System folder in Retroarch, they work fine, but I was wondering if there is a way to organise the ROMs in the folder?
E.g. can I create a folder for each Core and the BIOS it requires and still have the Cores find the BIOS ok?
No, this is something I would like, but it’s not implemented currently. Most go into ‘system’ and a few require a subdir, like dc or ppsspp.
Actually, this IS possible, I’ve set my build up this way. It just takes some work to make it happen…
Here is my RetroArch/System folder:
The way you do this, is create your folders and drop in your BIOS files.
Keep in mind, If we’re talking about something like dreamcast that has it’s own folder in the normal /system folder it needs to be inside the folder you are creating. For example, instead of: …/retroarch/system/Flycast/ you’d want to do …/retroarch/system/Flycast/dc/
Once you have your folders setup, you then need to go to retroarch/config and Manually edit the .cfg files for each core, so they look similar to this:
system_directory = "X:\Emulators\RetroArch\system\Flycast"
What this does is change that /system directory by creating a core-override for every core. Hopefully this is something they can implement eventually, because honestly it’s a really nice quality of life feature.
Cool, thanks this is really helpful 
I also recently posted about a DAT for the System folder: DAT for each core's BIOS available?
And the DAT itself is separated by system, so I’m wondering if I can create folders titled the same and they will be recognised this way without needing to override.
E.g. (from the DAT):
comment "Atari - 400-800"
rom ( name ATARIBAS.ROM size 8192 crc 7d684184 md5 0bac0c6a50104045d902df4503a4c30b sha1 3693c9cb9bf3b41bae1150f7a8264992468fc8c0 )
rom ( name ATARIOSA.ROM size 10240 crc 72b3fed4 md5 eb1f32f5d9f382db1bbfb8d7f9cb343a sha1 6dd53356159a129ed12367beb3b24a771d41adb0 )
rom ( name ATARIOSB.ROM size 10240 crc 3e28a1fe md5 a3e8d617c95d08031fe1b20d541434b2 sha1 f1f0741b1d34fb4350cf7cb8ab3b6ea11cdd8174 )
rom ( name ATARIXL.ROM size 16384 crc 1f9cd270 md5 06daac977823773a3eea3422fd26a703 sha1 ae4f523ba08b6fd59f3cae515a2b2410bbd98f55 )
comment "Atari - 5200"
rom ( name 5200.rom size 2048 crc 4248d3e3 md5 281f20ea4320404ec820fb7ec0693b38 sha1 6ad7a1e8c9fad486fbec9498cb48bf5bc3adc530 )
So I would create a folder titled ‘Atari - 400-800’ and one titled ‘Atari - 5200’ and place the correct BIOS in those? 
If it doesn’t work automatically I think I might try to setup the overrides to work this way to hopefully keep it easier to track the correct BIOS files are used.
Glad I could help haha. I felt so proud of myself for figuring it out a little while back so I’m glad someone else can use it. I actually set it up this way so I could zip the whole shebang up and create a backup for those times I have to reinstall a fresh version of RetroArch. (Plus there’s just something nice about having MD5 verified BIOS folders archived haha)
I gotta confess you lost me with this DAT thing though. I’ve never heard of this and I don’t know what I’m looking at. I looked over at romvault linked from that post but… yeah I’m at a total loss what any of that is :S
No, the cores won’t recognize the subdirectories. They’re hardcoded to look in only one spot, which is usually just ‘system’. You can do the override thing like SkyHighGam3r described and point wherever you want, but it won’t do it automatically.
Yeah sometimes I have an issue with a Core and the fix might be a reinstall (probably due a preference or something). So it’s handy being able to refresh everything quick 
The DAT can be used to verify the files using a hash (often MD5), they’re often used to verify ROMs from other collections; MAME, TOSEC, No-Intro, Redump etc.
I rely on them to know that my ROMs are correct; I’ve always used Clrmamepro https://mamedev.emulab.it/clrmamepro/ as I originally used it with MAME years ago. But recently I discovered RomVault https://www.romvault.com/ which can process multiple DATs at once, this is really handy for large sets of DATs like TOSEC, and it can also reorganise folders automatically, which may be handy with the BIOS files in Retroarch. The tools will read the DAT and compare it with the files you have, they will then rename, remove or fix your existing ROMs based on the information in the DAT.
Both might seem a bit complicated at first but I’d be lost without a DAT and a tool to help me sort/test ROMs 
Both sites have decent guides that explain how to use them.
Clrmamepro will keep a backup of any files removed by default, but I’m not sure if RomVault does the same; if you’re going to try either I would use a backup set of your ROMs just to be sure as if something is setup wrong it can delete all your files 
Ah, thanks, wishful thinking
I’ll have a look into overriding to sort them