VAX graphics

[Tony Duell]

> 
> Johnny Billquist wrote:
> > It might be that the graphic system have a color palette then, since 
> > obviously, there are other colors than blue possible, but none others 
> > are shown there.
> > Or else they have a 24 bit pixel depth, which would be very impressive.
> 
> Our grinell had more than one buffer, and you could do operations 
> between them too.

Another possibility is an I2S of some flavour. My model 70 and model 75 
machines have a 512*512 displayed resolution, and 24 bit colour (or in 
one case 30 bit colour). Agian you had multiple byteplanes which you 
could combine in all sorts of ways.They had a fairly simple parallel host 
interface, I have the Unibus card, there were others made to link to 
HP2100, DG Nova,etc. And an iterface converter that linked to a DR(V)11-W 
type of port.

Unlike the Grinell, I do have some documentation, including schematics. 
Just as well, my 70/E has 6 byteplanes (it could have up to 12 with 2 
more memory crates...). It conainst over 3000 4K DRAM chips (it's not 
3072, it's even more than that) and about as many TTL devices...

-tony