Anybody want to give a brief comparison of how these compare in practice to DDR4 and SSD storage? I assume it's "slower than the former, faster than the latter", but having an idea of the magnitudes would be useful.
These are byte addressable - they will look like RAM to the OS. (If you have a motherboard that supports them, there is a slight change to the spec).
To the application developer, the interface will be http://pmem.io/pmdk/ . Last I looked, there were several ways to do things, but the most commonly used would basically be allocating a chunk of memory and assigning it a file name so you could re-open it next time.
This is exciting because it could open up exciting possibilities like zero-CPU IO with DMA straight to persistent memory, "sleep" mode that is essentially free, re-thinking paging in modern operating systems, and generally re-thinking everything we've assumed since core memory.
On the same day we are talking about WASM microkernels in another thread. Things are getting fun again :)
That would be https://news.ycombinator.com/item?id=17187384
So the PC platform finally caught up with Amiga's RAM disk ;-)
Still, I do fondly remember my Amiga days!
But the speed and density seems to be a problem. E.g. it's still 2x slower than DRAM, but theoretically should be faster. It could also have 3 bits, not just 2.
It will be interesting to see the real benchmarks on this DIMMS. We all want to know if they're comparable to real DDR4 memory.
The current market is terribly overpriced (there's some debate on if there's price fixing with the big three or if it's a genuine shortage/supply problem with the Note recalls and new phone releases). DDR4 is nearly double the price it was the last time I did a build over a year ago. :-/
EDIT: Looks like these chips will be specialized for certain server boards/CPUs and only share the DIMM interface and not protocol.