What game system is my mother talking about?

My mother and I were having lunch recently and we got on the topic of video games and how much better they have become over the years, then she mentioned a game system which I have never heard of. She couldn't remember the name of the system, but she claims it had small, credit card like disks which slide into the system. According to her she had rented it from a store for my older brother and they had it only a while before said store went out of business. She also told me that this was just before we bought our first Nintendo system. Anyone have any idea what the heck she's talking about? I am super curious!What game system is my mother talking about?Hmm...Maybe the Sega Master System? Not really sure. There were a lot of unpopular game systems Americans never heard of. This one was only really popular in European and the Brazilian market for some reason.What game system is my mother talking about?It could be the megadrive, or N64. (I think the megadrive is also called genesis.) They had sliding cartridges that go into the console and were quite popular.What game system is my mother talking about?it could have been an atari i used to have one but thats all i no