LASERS! && Freemont Street LED array (was Re: Cray J932SE (was Re: Straight 8 up on Ebay just now))

Paul Koning paulkoning at
Wed Jul 20 08:19:32 CDT 2016

> On Jul 20, 2016, at 9:12 AM, Mouse <mouse at Rodents-Montreal.ORG> wrote:
>> As far as sending video from a computer frame buffer, I think it
>> might be way too fast.
> I wouldn't be doing that.  I cited the cg6 by way of contrast.  How the
> points get into the display hardware is still open, but a framebuffer
> seems unlikely to be involved.  (I suppose a framebuffer with something
> like DVI-D could be used as a way to continuously replay sequences very
> fast, but it has its limitations.  I'd rather build a hardware ring
> buffer, but I tend towards hardware hackery.)

Given modern processor speeds, an obvious answer is to do it the same way the CDC mainframes drive the console: a program loop feeding coordinates to the interface.  You just need a loop that takes less than the acceptable refresh interval (30-50 ms or so) which isn't hard to do.  Especially since the deflection performance is likely to be the limiting factor.


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