Application-accessible nvram/cache for Linux?

[Michael ODonnell]

> Worst case, you can open using O_DIRECT, which specifies direct
> read/right access.  The only limitation really is the reads/writes
> need to be aligned to the block size of the device.
>
> Better would be to tell the OS it's OK to cache it, but a direct
> write is needed.


Negative.  Even though Paul didn't supply specifics it's still
clear that for a mapped file to provide the same granularity and
persistence as battery-backed RAM it would have to be updated
after *each* write to memory.  Nothing that's yet been mentioned
here will yield that sort of behavior.  I suppose it would be
possible to simulate it by (say) marking the region of memory
in question as Read Only and then having the SEGFAULT handler
update the corresponding block on the device, but...  ick!