Core memory emulator using non volatile ram.

[Eric Smith]

On Sat, Dec 15, 2018 at 11:55 AM Chuck Guzis via cctalk <
cctalk at classiccmp.org> wrote:

> On 12/15/18 10:01 AM, Guy Sotomayor Jr via cctalk wrote:
> > FRAM or MRAM.  I make extensive use of them in my projects.
> >
> > Everspin has a few (all SMT and 3.3v).  As I recall they run ~$20/ea for
> 4Mb (512K x 8 or 256K x 16).
>
> As neither MRAM nor FRAM requires a write-after-read refresh, I fail to
> see the "realism" in this that couldn't be satisfied with simple
> battery-backed RAM or even flash-backed RAM.
>

FRAM requires write-after-read refresh, but it's done internally to the
part. That's why FRAM has limited read endurance; each read also does a
write.  FRAM endurance is typically 10^14 cycles (check the datasheet of a
specific part), which is adequate for most uses.