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Re: //e, //c, //gs Questions
On 29 Oct 1998 07:44:23 GMT, supertimer@aol.com (Supertimer) wrote:
>spec@vax2.concordia.ca (Mitchell Spector) wrote:
>
>> It may support 1024x768, but certainly *not* at 24-bit
>>color depth. [anti-Second Sight rhetoric snipped]
>
>Wrong Mitch. The Second Sight manual, page 18,
>clearly states:
>
>"Tru-color mode is similar, but each pixel can be
>any of 16.7M (million) colors" (the paragraphs
>before it detail the three color modes of the Second
>Sight card, indexed, hi-color, and tru-color in this
>paragraph).
>
>Checking with my calculator, 16.7M is 2 to the 24th
>power or 24-bit color!
Nope, Mitch is right on this one. The Second Sight can only do 24 bit
colour in 640x480 mode if the card has 1 MB of RAM installed. Here is
a chart of the three main resolutions and the maximum colours allowed
on a 1 MB SecondSight card:
Resolution Max Colours Bytes/Pixel Proof
---------- ----------- ----------- --------------------------
640x480 16,277,216 3 640*480*3 = 921,600 bytes
800x600 65,536 2 800*600*2 = 960,000 bytes
1024x768 256 1 1024*768*1 = 786,432 bytes
A SecondSight card with only 512k installed can only be used in
640x480 or 800x600 mode with a maximum of 256 colours in each mode.
(307,200 bytes and 480,000 bytes used respectively)
>Don't knock it if you have never used it.
I don't have one and haven't tried it but I will knock it because it
is impossible for a SecondSight card to display 24 bit colour in
1024x768 mode. :-)
If the SecondSight was designed to be expandable beyond 1 MB of RAM
then it might have been possible. It would require 2,359,296 bytes of
memory to be able to do 1024x768 with 24 bit colour.
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Jeff Blakeney - Dean of the Apple II University on Delphi
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