During the 1990s, Nintendo and Sega experimented with delivering games on demand via various transmission media. The Sega Channel was a subscription-based service that allowed Sega Genesis owners to temporarily download games to a local adapter (1) for play. The BS-X Satellaview provided similar functionality for the Super Famicom in Japan over Satellite TV networks. However, users could store downloaded games indefinitely in interchangeable Memory Paks (2) that would fit into a larger adapter (3).
Key:  Sega Channel Adapter (Genesis, 1994),  Nintendo BS-X Memory Pak &  Nintendo BS-X Special Broadcast Cassette (Super Famicom, 1995)