🚀 go-pugleaf

In article <1992Aug30.113052.9729@shograf.com> jimb@shograf.UUCP (Jim battle) writes:
| 
| I feel that the 3.75x system bus bandwidth difference between a
| ShoGraphics PEXStation and an SGI Indigo would make a bigger difference
| in system performance than having a funky user-accessible DMA capability.

I agree completely.  The extra system bus bandwidth would be useful in
many more contexts than the extra DMA functionality, so it should be a
bigger win overall.

| I agree with you that for some cases the OpenGL approach is a significant
| win for a specific machine, but I remain unconvinced that it matters that
| much in general.

Perhaps we have different opinions here because my position is a little
higher on the food chain.  As a software guy, it's important to me to
select the interface with maximum implementation flexibility and best
performance on as wide a range of machines as I can envision, because
I'll have to live with it for at least a decade.  If the OpenGL
approach allows me to squeeze more performance out of some classes of
machine (without unduly degrading others), or if it allows me to
configure systems more flexibly (e.g. reducing the coupling between CPU
cost/performance and graphics cost/performance) or if application
developers tell me the interface allows them to complete their ports
more quickly, then to me it looks like a big win.  In your case it may
look less important because your hardware base is one of those for
which the choice of graphics interface doesn't matter.

| ...

Thanks for the comments on the i860.  I've participated in some
graphics design efforts using it, and I remain favorably impressed.

| |                                      ...why not choose a 3D graphics
| | interface that allows you to reduce bus bandwidth requirements in the
| | cases where that results in performance or price improvement?
| 
| I guess political reasons.  ...

Probably so.  Technical issues are only one factor in the business
decisions of all the companies you mentioned.  Even financial issues
aren't dominant; otherwise companies would be more careful about
evaluating full productization costs rather than pricing the sample
implementations alone.

| Thanks for your response; sorry if I've mangled the content of your
| arguments by excerpting it this way.

No problem.  This discussion has been well worthwhile.

Allen