We've got a 64K-word TX-2 core memory on display at the MIT Museum. [update - here's a link <a href="http://tinyurl.com/5mve8b" rel="nofollow">http://tinyurl.com/5mve8b</a>]<p>Back in 1975/6 I was using a DEC LSI-11 that had core memory. I forget how much but it was enough to run FORTRAN.