Re: AppleWin problems

[rubywand@swbell.net]

Edhel Iaur, Esq. (drsmooth@relex.com) writes ...

<<
On Tue, 25 Feb 1997 22:15:41 -0800, Rob <roberta@inreach.com> wrote:

>I'm curious to know if you have ever seen a real Apple // color
>display?  The graphics are blurred.  That is normal.  It had to do 
>with the hardware tricks that Steve Wozniak had to do in order to 
>get a color output using off the self parts.  The drawback was the 
>fuzzy color display.  AppleWin just emulates a real Apple too well.
>

I read that the various oddities of video are a side effect from
trying to cut down on the amount of memory used for video, since
memory was so expensive then (16K of memory!?  WOW, you must be 
RICH!)
>>


     Maybe, as Rob suggests, some PC users have simply never seen 
anything less than VGA resolution. Such a user might, conceivably, 
describe an Apple2 dithered-color hi-res display as "blurry".


     Apple2 hi-res could have been better; but, limiting memory IC 
expense does not seem to have been a vital consideration.

     In 1980, a true 280 x 192 16-color display would have been well 
worth the cost of just the 27k per screen of memory IC's required. 
(280 dots at 4 bits/dot = 1120 bits/line. 1120/8 = 140 bytes/line. 
140 x 192 lines = 26880 bytes/screen.)

     Such a display would be within the capabilities of popular 
moderate cost composite monitors of the time. Text would still be 24 
lines at 40 characters/line; but, it could be displayed in 16 colors.

     The biggest technical problem with our 27k/screen display is 
that the 6502 addresses just 64k. 27k gobbles more than three times 
as much memory address space as today's hi-res. Two such hi-res 
"pages" would use up nearly the entire space available for 
programming + DOS 3.3. 

     The solution, bank-switching, would have significantly increased 
circuit complexity and IC count. Then, you can add the memory IC's, 
mem support IC's, and extra video support IC's. All of which lead to 
a larger, more costly motherboard.

     As it is, the display design cuts corners at every opportunity; 
and, many of these cuts impact display clarity. Dot placement 
determines dot color and adjacent dots usually interact. Text in the 
"Text window" below a color hi-res display always looks a bit odd 
because Text characters employ single-dot-width lines and it is 
impossible to display a single white dot on a hi-res color screen.

     Naturally, a major factor in designing Apple2's graphics display 
was the competition. At the time, there wasn't any. (TRS-80, 
remember, was hyping B/W character graphics.)

     Apple2 could have offered better graphics; but, why bother? Back 
in 1980, hi-res looked great! And, Apple II+'s sold like hotcakes.