[Sesse__]

Are you talking about the fact that NVMe works by MMIO and DMA? So is pretty much any SATA controller, so there's no inherent difference there (there are _many_ years since the dominant way of talking to devices was through programmed I/O ports). Unless you have a NVM device with host-backed memory (as discussed elsewhere in the thread), it's not like the CPU can just go and poke freely at the flash, just as it cannot overwrite a SATA disk's internal RAM or forcefully rotate its platters. It can talk to the controller by placing commands and data in a special shared memory area, but the controller is fundamentally its own device with separate resources.