This video card was Apple's first foray into the world of accelerated
graphics. The "accelerator" is an AMD 29000 RISC CPU, for which I believe
there is a gcc back-end (i.e. we could, in principle, write code for it).
Apple essentially dropped QuickDraw into the RAM on the card, started up
the 29000 CPU, and patched MacOS to call those routines "interprocessor"
(I'm not privy to the details, alas) which had the salutory effect of
accelerating the graphics for *all* the video in the system, not just the
monitor attached to the the card - it was really a graphics co-processor
system.

As I understand it, however, there were found to be "too many" applications
playing beneath QuickDraw's API (behind the back of the co-processor) that
thought they "knew" how the system was configured, and the 8*24 GC's
presence in the system violated those assumptions (i.e. application go
crash, boom), so the card never sold all that well. They were also rather
expensive (surprise - hardware from Apple). Apple officially deprecated
their use with the Quadras (i.e. any 68040 or later system; probably had
cache coherency issues).

I have one of these beasts if anyone wants it. I live in the SF Bay Area.

	Erik <fair@clock.org>
	Mountain View, CA