From: hasty@netcom.com (Amancio Hasty Jr)
Subject: Re: public S3 design (Was: Free software and ... Diamond products)
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Sun, 4 Oct 1992 15:42:27 GMT

In article <1992Oct3.055409.17914@gagetalker.com> scotty@gagetalker.com (Scott Turner) writes:
>In article <BvGoLF.8nn@pix.com> stripes@pix.com (Josh Osborne) writes:
>|> In article <BvCyt0.JG4@immd4.informatik.uni-erlangen.de> Torsten Duwe  
>(duwe@informatik.uni-erlangen.de) writes:
>|> [...]
>|> >Doesn't performance depend solely on the main (bus/memory/whatever) clock ?
>|> >... would be a bad thing if drawing speed was closely coupled to the pixel
>|> >clock. 
>|> 
>|> With normal DRAM (i.e., not VRAM, not duel ported RAM) if the shifter needs
>|> to output 65 Mega Pixels per second (assuming 8bits per pixel) 65 Mbyte/sec
>|> of bandwidth is used to feed the shifter, which is 65Mb/sec you can't use to
>|> transfer data to the DRAM.
>|> 
>|> [...]
>|> >In my opinion local bus is unnecessary if you have an 'intelligent' SVGA to
>|> >give complex commands to. Only memory to screen bitblt is an issue but that
>|> >should be solved using more video RAM - hope the '928 is able to address  
>more
>|> >than 1 Meg.
>|> 
>|> Well please optimise copy plane of pixmaps with xor on and have enough RAM
>|> that all of xtanks pixmaps can be resident (I think there is over 1M of them
>|> once rotated out, if not I know there is over 500K of them).  [...]
>|> 
>|> >[...]
>|> >>(4) S3 corportation provides a software development kit
>|> >Yup! They're very DOS-infected but nice people.
>|> 
>|> I thought they had a windows bias, the 911 isn't very fast unaccel'ed
>|> (isn't as fast as, say, the ET4000), and most DOS programs arn't accel'ed.
>|> Not that windows is all theat diffrent from DOS...
>Interesting discussion guys, but you're both missing the big advantages to
>using something like local buss or an S3/8514 card.
>
>The single biggest thing you need is unbanked access to the video memory.
>Next is mouse in hardware. Then comes video refresh rate vs VRAM/DRAM.

The 8C911 is not available with DRAM
>
>Not having to look over your shoulder to make sure you haven't switched
>banks or drawn on the cursor make a huge difference in performance. The S3
>chip has an on board mouse and having an 8514 interface it has unbanked
>access to the video memory.
>
>But massive bandwidth to the memory doesn't always pay off. I've benchmarked
>the ATI Graphics Ultra against the ATI GraphicsVantage. The Ultra has over
>twice the bandwidth of the Vantage and yet is only 20% faster in the windows
>benchmarks.
>
>I did a BLIT port of X11R4 to SysV386 3.2 and using the 82786's on board
>mouse hardware almost doubled the speed of the server (using the onboard
>drawing engine also gave it a BIG kick in the pants, too bad the damn thing
>died, sigh.)
>

>Western digital was shopping around a chip earlier this year that was designed
>specifically to speed up X. It pratically ate X straight (like the 82786) and
>thus might be an interesting chip to play around with.
>

Is the above mentioned chipset the S3?

>Scotty
Tnks Scotty for the info on the advantages of using the hardware cursor.

First off, I found an S3 svga card by Actix which I can set the dot 
clock values. Actix's telephone number is 408-986-1625.
You may also obtain the GraphicsEngine, the S3 card, from Palo
Alto Computers. They are located in Palo Alto, Ca. I don't have 
my dealers number. Palo Alto Computers sells the GraphicsEngine
for less than $250, and if you obtain the card  from Actix they 
will sell it for the list price of $300. All technical questions
about the GraphicsEngine should go to Actix. 

The GraphicsEngine comes with 1 MB of VRAM and there is no
S3 8C911 DRAM version.

Now on the X server side of things, I have modified an 8514/A
X server to work with the S3 chipset. The server seems
to work and it is fast. For instance moving a window around
an releasing the mouse button, the server draws the window
as soon as I release the button. The impression that I have 
is that it feels faster than a Sun Workstation IPX!
The major problem that I have is that the server seems to draw half
of the characters. 
When all the major problems with the X server get eliminated,
I will be more than happy to post my xbench results.

The 8514/A X server was developed under Linux and the S3 X 
server is being developed under 386bsd. The work to get the
GraphicsEngine working started on Tuesday and on Saturday I was
enjoying  graphics with a resolution of 1024x768 interlaced.
I had previously modified the 8514/A server to work with the
S3 chipset. The new work was related to initializing the 
S3 properly,e.g., setting the dot clocks and the Horizontal and
Vertical Timing values, etc.

My X server uses the extended graphics functions on the S3 and
does not use the vga banking.

Many thanks to Kevin Martin for providing the 8514/A X server.


Enjoy,
Amancio Hasty