Some terminals I worked on years ago used shift registers connected in a loop as memory...
Leonard
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of John Parsons
Sent: Saturday, May 02, 2015 12:15 AM
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:6909] Re: Altair Cyclops Info Wanted
A little detective work that needs a sanity check:
Regarding Gary's idea of using a 4106 or similar: the device shown in the Popular Electronics article makes 30 reads of the memory chip to generate a frame. The output of each bit on each scan is amplified and used to generate a dot, with the dot intensity depending on the charge of the bit in the RAM on that scan. That will give a grey scale dot on the 'scope. The 4106 refreshes the memory on every read, so the bits will always be either a 1 or a zero, depending on the light. The article Gary mentions has no grey scale, only black or white. So no chip that refreshes on every read can be the chip in the Cyclops.
So that leaves another dilemma: if the chip can't refresh on a read, and has no refresh pin, how can a DRAM be the chip? Is there any other refresh mechanism that was in use in 1975? If not, it seems the memory must be static.
Where are all the semiconductor engineers? I guess they have been replaced by computers. We're doomed!! :-)
JohnP
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