[runeks]

> There are several storage class memories that are nearing commercialization.

I'm very interested in this. Could you point out which technologies that are near ready for commercialization?

My understanding is that the current cost is orders of magnitude higher per unit of storage for these new technologies compared to NAND flash or even DDR3 RAM. But of course, a dedicated fab could change that very quickly.

[jhallenworld]

Well nvDIMMs are available right now (from companies like Netlist, Agigatech, Viking, Smart, Micron). This is DRAM with an analog switch, a controller and flash memory. When you lose power, the DRAM is disconnected from the processor and the contents are copied to the flash. The newer technology might be cheaper, but I thought so far the write performance is not as good as DRAM.

The issue is the cache: the data is not non-volatile until it has been written back to DRAM. Even then, you need some advanced warning of a power outage for it all to work.

Unibus (bus for PDP-11 core memory systems) had an early warning signal, to give the memory controller a chance to write back the previous (destructive) read.

[bahahah]

Components are available on the market now based on PCM, MRAM, and FRAM. I know that Intel has large productization, not research, teams working on a variant of SCM. Near means 2-3 years though. Research exit to market ready is always a 3-5 year cycle when process engineering is involved.