RetroX forums

Hi Franco in the beginning it was only mame I think that could be loaded from zip files , what emulators now play zipped rom files ie all the emulators on your retrox or still only mame , could you advise please

Only MAME play zipped games, because that's the official file format for that emulator.

All other emulators handle uncompressed files, so RetroX can scan and recognize your compressed games, but before playing it RetroX must uncompress them to run the emulator. That will require additional space.

So your options are:
a) zipped: it uses less space in your original storage, but it will use more space in your internal storage, the game must be unzipped and the unzipped copy will be put in your internal storage for the emulator to run.
b) unzipped: it uses more space in your original storage, but the emulator will just use that copy to start the game, no additional work or space needed

Explained perfectly Franco, I wouldn't want to use any internal storage space so will go with unzipped for all formats except mame , great response and explained very well, thank you kindly .

When a zipped rom is unzipped and stored on the internal storage, is this deleted once the game closes or kept on the device. if so where ?

It is kept in the device until you uninstall the game from the game details screen or the manage games option -> uninstall games.
It is stored in what Android considers to be the "Primary external storage", in some device that's not an external drive but internal.