Date   : Thu, 25 Aug 2011 16:05:49 +0200
From   : rick@... (Rick Murray)
Subject: Tube ROM

On 25/08/2011 09:53, J.G.Harston wrote:

> That *IS* a 4-colour MODE 0 - ie MODE 8 (and a 16-colour MODE 1 - ie MODE
> 9). Read the text files and run the programs.

???

Quote:
   MODE 8 (four colours, 80 columns) is based on MODE 1 (four colours,
   40 columns). MODE 9 (16 colours, 40 columns) is based on MODE 2 (16
   colours, 20 columns).
   [...]

Or do you mean MODE 8 (based on MODE 1) is essentially equivalent to a 
four colour MODE 0? The problem is, it depends if you're looking at it 
as a point of view of text or graphics. You may then have a MODE 0 like 
text display mode with 80?32 characters on screen, however both the 
resolution of this and the screen as a graphics area is only 320?256 
which is less than MODE 0's 640?256... Put simply, a true four colour 
MODE 0 will not fit. There isn't 40K in the machine!


As an aside, wasn't there a game (Elite?) that switched MODE partway 
down the screen, like the exterior view was drawn in MODE 0 and the 
cockpit at the bottom was drawn in MODE 2? On the same screen, at the 
same time? I bet that was an interesting design!


Best wishes,

Rick.

-- 
Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...