Supporting filesystems in persistent memory

Posted Sep 11, 2014 9:01 UTC (Thu) by dakas (guest, #88146)
In reply to: Supporting filesystems in persistent memory by reubenhwk
Parent article: Supporting filesystems in persistent memory

Volatile storage has always been considerably faster, smaller in capacity and far more expensive[...]

"Always" is such a strong word. There were literally decades where core memory was persistent because, well, consisting of magnetic cores.

HP at the current point of time appears to be betting a significant part of its assets on memristor technology. It does not look feasible to make it "much faster and more volatile": they want to move the CPUs to that technology as well, so there will be no issue of "better fit/worse fit" as there is with static RAM vs dynamic RAM vs block devices.

I'd like to see them pull this off and make computing more exciting again than the "more of the same, just more so" developments of the last 30+ years.

Supporting filesystems in persistent memory

Posted Feb 12, 2016 9:24 UTC (Fri) by roblucid (guest, #48964) [Link]

And as one of the links in article explains, core memory was not only slower than RAM, but the persistence was only 80% reliable, frequently a colder style boot was required.

Fast memory has needed to be closer to the core, for example modern L1 cache, technologies which include RAM inside the CPU package (EDRAM/HBM2) are intended for high bandwidith whilst providing low latency. A device on the end of some bus, that's plugged in, can NEVER compete with the short physical connections of on chip RAM, so there's very good reason to believe the miracle people want to believe, will prove to have engineering tradeoffs (for example the EROS persistent RAM store, was disk backed therefore with log write throughput is FAR lower than RAM and it's performance relied on cache and the hot checkpoint area of disk reducing seeks for "85%" of accesses).