Any solid-state media you can access is almost certainly NAND. There's a second kind of flash memory called NOR, but it's gradually disappearing. I think it's relegated to EEPROMs and similar embedded uses. The number of applications where its advantages matter are outweighed by the seventeen bajillion dollar market for higher-capacity NAND. All the research money and foundry tech are going toward the one that'll let them sell 1 TB SSDs for $20.