I wrote:
> It was "Williams Tube" memory.  It did need to be refreshed, and did not
> acchieve tremendous density.  It also was not terribly reliable.  It is
> rumored that the first video games were played on these; kinda neat having
> the frame buffer and display in the same device.

myke predko <myke@PASSPORT.CA> replied:
> I think if you look back at the old computer games, you'll see that the
> screen buffer is used for both video memory and program memory.  This also

I'm not sure, but I think you may have missed the point.  I wasn't talking
about the frame buffer being part of main memory, or vice versa.  That is
very common.  There have even been some x86 PCs that do that, but AFAIK only
the Cyrix MediaGX based PCs do it now.

What the original poster and I referred to was a device in which the
computer's main memory literally was the display tube.  The use as a frame
buffer was completely incidental.

I wrote:
> I wonder how difficult it would be to make such a thing now?  And use a PIC
> to drive it, of course!

myke wrote:
> It shouldn't be that hard; a PIC ZX-81?  I think that would be an
> interesting project!

That defeats the purpose.  The question is whether it is possible to make
a Williams tube memory.  Having a RAM frame buffer is way to common to be
of even the slightest interest.

Cheers,
Eric