As shown during its reveal trailer this morning, Nintendo's Switch console will run on cartridges instead of optical media.
These aren't your papa's bulky Nintendo 64 carts, though. Switch carts are roughly the size of Nintendo 3DS game cards, and are inserted into a slot at the top of the tablet-like device. This is in line with months of rumors indicating that Nintendo would leave Blu-Ray and DVD storage media behind in favor of cartridges.
Nintendo Switch is a console/handheld hybrid that runs on a tailor-made NVIDIA Tegra processor and will launch next March. For more info, check out Shacknews' comprehensive summary of today's unveiling.