[cctalk] Re: Computer Museum uses GreaseWeazle to help exonerate Maryland Man

[Will Cooke via cctalk]

> On 02/01/2023 3:51 PM CST Paul Koning via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
ot sure about that. What sort of numbers are we talking about?
> 
> If all else fails there's core memory, which as far as I remember is pretty 
> much unlimited for both read and write.
> 
> paul

I don't know for sure and can't find any references, but I strongly suspect 
that core memory would wear out over time, as well.  My reasoning for this is 
the because in principle it works the same as FRAM.  I usually refer to FRAM as 
"core on a chip."  Over time, the magnetic domains in FRAM tend to stay in one 
polarization or another.  I see no reason why the magnetic domains in core 
wouldn't do the same.  However, a single core is probably bigger than the 
entire FRAM chip so there are a LOT more domains.  That means it would take a 
proportional amount of writes to wear out -- let's just say a million times.  
In addition, core access was in microseconds, whereas FRAM and other modern 
memories are in nanoseconds.  So it takes something like 1000 times longer on 
the clock on the wall to perform the same number of writes.  So in the end 
something like a billion times longer on the calendar to wear it out.

I would be very interested if anyone actually knows and especially if there are 
references available.

Will