That can potentially work, but only by getting the filesystem/block storage/PCIe layers of the IO stack out of the way, and even then it's only plausible for Op

That can potentially work, but only by getting the filesystem/block storage/PCIe layers of the IO stack out of the way, and even then it's only plausible for Optane or similarly low-latency storage. It'll never work for flash, because the latency of flash will never be low enough.