Following the Doctor V64's success, Bung released the Doctor V64 Jr. in December 1998. This was a cost-efficient condensed version of the original V64. The V64jr had no CD drive and plugged into the normal cartridge slot on the top of the Nintendo 64. Data was loaded into the V64jr's battery-backed RAM from a PC via a parallel port connection. The V64Jr had up to 512 megabits (64 MB) of memory storage. At the time this was done to provide for future Nintendo 64 carts that employed larger memory storage. The prohibitive high costs associated with ordering large storage carts kept this occurrence at a minimum. Only a handful of 512 megabit games were released for the Nintendo 64 system.