Date   : Wed, 12 May 1993 10:31:43 +0100 (BST)
From   : "I Stephenson" <ian@...>
Subject: Re: A new thing...

>After reviving an old project, I hit upon the solution (made easier by the
>fact I now have a master with shadow ram, and didn't before). I've  
>successfully
>doubled the vertical resolution of the bitmapped screen modes, giving a
>maximum of 640x512 in mode 0.
>
>Having done this, I haven't any idea what to do with it! :-)
>
>The refresh rate is effectively halved, which seems to be too slow to stop a
>certain amount of flicker under the wrong conditions (isolated pixels
>flicker). But it's not bad. Text looks good.
>
>Anyone got any ideas for this?
>
Excellent!
I figure that this works by switching the banks between the interlace, so lines  
from each bank get interleaved(?). I had wondered if this was possible, but I  
don't have shadow RAM to try it with (If this works well enough I might get  
some!). Once selected how well does it sit with the rest of the system (ie is  
it transparent?), or are special drivers needed? Will it work with any shadow  
board?

The obvious thing would be to develop some sort of windowing environment (the  
old res realy wasn't enough for this). Once I get BCPL running I was planning  
to add some O-O extensions (as in Objective C) - I consider such things  
esential for windowing. It would then be pretty easy to get something like the  
original Mac finder up and running.

Have you tried converting the GIF viewer to it? Mode 0 stuff looked pretty good  
-twice the res would be excellent.

Keep text the same physical size, and but write some font drivers. Double res  
would allow you to add serifs and other cute features without overly crowding  
things.

Acorn failed to see the graphics revolution, and hence support for the above  
stuff is limited. Therefore its probably something worth invsetigating further.

Ian