Editing Doctor V64 (section)

=== Saving game progress ===
The second problem concerned saving progress. Most N64 games are saved to the cart itself instead of external memory cards. If the player wanted to keep their progress, then the cartridge used had to have the same type of non-volatile memory hardware. Alternatively, Bung produced the "DX256" and "DS1" add-ons to allow (EEPROM and SRAM respectively) saves to be made without using the inserted cartridge. These devices were inserted into the top-slot of the N64 with the game cartridge being then inserted into the top of them to just provide the security bypass. Save slots on the DX256 were selected using an alpha and numeric encoder knobs on the front of the device.