[rescue] octane question

[Joshua D Boyd]

On Mon, Jan 14, 2002 at 03:16:10PM -0500, Big Endian wrote:
> >Err, you have an octane don't you?  What is it's graphical setup?
> 
> No I don't but I've dealt with IMPACT indigo2s and I've done a LOT of 
> research on the octane (read mental masturbation over the octane). 
> The *I cards on the octane are repackages of the IMPACT cards for 
> indigo2s and use XIO instead of GI)64.  Octanes w/ MXI graphics 
> report "4 TRAMS" to /usr/gfx/gfxinfo and hinv.  If anybody has seen 
> differently I would *LOVE* to be proven wrong (and then grab an MXI 
> octane).  The nice thing about XIO is the raw throughput 
> (800mb/sec/direction burst)  so you can *STREAM* textures in and out 
> of ram.  This is hard to do w/ a lesser machine or even a greater 
> machine (EBUS is 1.2GB/sec but its a shared bus and I'm not sure if 
> thats a full duplex figure).

I don't know what EBUS is, but on the O2 you are always streaming textures in
and out of RAM.  That it was designed to do that well is what makes it superior
for doing things like volumetric vizualization and image processing.
 
> >I'll have to write up a sample program to test what the capabilities 
> >of octanes
> >with low/no TRAM are one of these days.
> 
> You can still get CPU based texturing on the SI and SSI cards.  I'm 
> sure that it sucks... but you can do it.  The O2, even with all the 
> stuff they do on the CPU *HAS* hardware texture because CPU texture 
> sucks.  I wouldn't bother testing w/ no TRAMS.

Well, there are two questions.  An SSI + TRAM has hardware texturing.  We are
led to believe that the TRAM is texture ram.  So, the first question is TRAM
just texture ram?  The second question is does the SI have hardware texturing?
As the O2 shows, you can have hardware texturing without texture ram, and if 
the TRAM is just ram, then that would mean that the SI would have to have 
hardware texturing.  And with this we are left asking if the TRAM is just ram
and the SI has hardware texturing, is there a software setting forcing it off 
(ie making it act like there is no hardware texturing when no TRAM is sensed so
that they can badget you to spending $$$ on a TRAM that doesn't really do any-
thing anyway since your textures are too large).

A sample program is usefull to make sure that the texture streaming actually 
works adquately on the Octanes with the cheapest texturing option.  And once it
is written, why not ask someone with superplane SI graphics to give it a test 
run?  Worst case is that it would be slow, and we would know not to count on
getting a useable Octane for less than $1k.

-- 
Joshua D. Boyd