There is an OS in current use that could have used Optane directly. It used to be OS/400 on an IBM machine called AS/400. Now the machine is an "i-series", and

There is an OS in current use that could have used Optane directly. It used to be OS/400 on an IBM machine called AS/400. Now the machine is an "i-series", and I think emulated on a POWER machine. Under OS/400, throughout the life of the machine, malloc will never return the same address twice. If you have an address (128 bits), you can see the last thing written there, in perpetuity. And, a program started up will run until it dies. Shut down, start up again, and the programs only notice time passed. If you get a new computer, you shut the old one down and start its image on the new hardware, and again the programs don't notice. Amusingly, much of the OS was coded in pre-1990 C++, basically Java without the GC.