Game Storage

Before you start adding your games, please take the time to understand how data storage is structured on KNULLI. This might be helpful, especially when you already have experience with other CFWs and want to migrate your data.

The /userdata folder

KNULLI supports single and dual SD card setups. Internally, KNULLI has a folder called /userdata where all your data (games, screenshots, bezels, saves, configurations, themes, etc.) will be stored. On a single-SD-card setup, the /userdata folder will always point to the SHARE partition of your primary SD card. If you have a device with more than one SD card slot and choose to create a dual-SD-card setup, the /userdata folder will point to the main partition of your secondary SD card instead.

Consequently, you will not be able to use the SHARE partition of SD 1 and SD 2 at the same time. Only one of those SD cards can be mounted as /userdata at a time. When you access your storage via SMB network transfer, you will only find one SHARE folder, which will always point at your /userdata folder. Therefore, when running a dual-SD-card setup, your internal SHARE partition will neither be used by KNULLI, nor be accessible via network transfer.

Internal and external storage

You can switch between single/dual SD card mode by following the steps in the section about Using a second SD card. Basically, by switching between internal/external storage, you just tell KNULLI which drive/partition /userdata should point to.

Understanding mounting on Linux

Windows users might not know this: On Linux systems, drives are not addressed by "drive letters" like you know it from your Windows machine. Instead, Linux mounts the drives into folders. The Linux file system does not know any drive letters at all, it consists of just one file tree with / being the "root" of the tree. Every folder that exists is a subfolder of /.

You might imagine / to be roughly comparable to C:\ on your Windows machine. Try to imagine that, when plugging an USB stick, the stick will not appear as D:\ but as a folder on C:\, e.g. C:\media\my-usb-stick\.

KNULLI is a Linux, so it uses the Linux file system. More specifically, KNULLI always needs to have a folder called /userdata (again, roughly comparable to C:\userdata) where KNULLI expects all your data (games, themes, saves, etc.) to be located. However /userdata is also a mount point for a drive. By switching between internal and external, you basically tell KNULLI where /userdata should point to after the next boot - it is either the internal SHARE partition or SD 2.

KNULLI expects all your data to be in /userdata, it does not look for games, themes, or anything else outside of the pre-defined folder structure. This is why it is not possible to use both SD cards as game storage at the same time.

Pre-defined folders for your data

Inside the /userdata folder, you will find subfolders where you can store your games and other files. After installing for the first time, KNULLI will create and populate all these folders automatically. The most important folders for you to know are the following:

• /userdata (corresponds to either the SHARE partition of your primary SD card or the main partition of the secondary SD card)
  • /bios is the folder where you can store your BIOSes.
  • /cheats is the folder where you can store your cheats.
  • /decorations is the folder where you can store your decorations/bezels.
  • /music is the folder where you can store MP3 and OGG files to have them play as background music on EmulationStation. (The songs should have a sample rate of 44100Hz and a bitrate of 256kb/s max.)
  • /roms is the folder where you can store your games. Inside the folder you will find subfolders for all supported systems. Simply place your game files into the folders of the system the game was made for, e.g.
    • /snes is the folder where your SNES games should be stored.
    • /gb is the folder where your Gameboy games should be stored.
    • /ports is the folder where your ports (including PortMaster should be stored.
    • ...
  • /saves is the folder where your savegames will be stored.
  • /screenshots is the folder where your screenshots will be stored.
  • /system is the folder where your settings will be stored. You should not change anything in here, unless you are absolutely sure that you know what you are doing. However, it can't hurt to include this folder in your backups.
  • /theme-customizations is the folder where your theme customizations will be stored.
  • /themes is the folder where your themes will be stored.

KNULLI only scans for games in the subfolders of the roms folder. Games which are stored anywhere else will not be recognized as such. If you are unsure, which folder to choose for your games, we strongly suggest to have a look into the Batocera Wiki!

KNULLI is a Linux system which is case-sensitive. Consequently, you should pay attention to capital letters when renaming folders or migrating folders from other systems/devices.

For details about the files which are required/supported for each system, have a look into the Systems section of the wiki.