On Thu, 13 Nov 1997, Nathan Raymond wrote:

> On Wed, 12 Nov 1997, Allen Briggs wrote:
> 
> > > It seems to me that the hardest part of supporting IDE on Mac would be
> > > figuring out how the interrupts are handled.  After figuring out these
> > > two unknowns, it should be a matter of compiling the wd driver into
> > > the kernel..., shouldn't it?
> > 
> > Nope.  I highly doubt that Apple used a standard IDE chip/cell.  Maybe
> > they did, but I really expect that they designed their own.  "to keep it
> > cheap"
> > 
> > -allen
> 
> If its any help, the Quadra 630 was the first desktop to impliment IDE
> (the PowerBook 150 being the first portable).  The Q/P630 IDE circuitry
> doesn't support *any* extended PIO or DMA modes.

Actually, the Q/LC/P630/640 supports PIO Mode 3.  I have a Performa
640, and have also worked with a Performa 636.  As far as
"non-standard" hardware on the drive or some such, I removed the original
drive from the 640 (it was identical to the one in the 636) and put in a
Western Digital Caviar 32100, with no problems. Since then I have used the
old drive (with no problems) in one Win95 box and one Linux box.  It is
identified as a Quantum Maverick 540 (aka Quantum Prodrive) by the BIOS.
I find it difficult to believe that this is a "non-standard," proprietary
version of IDE...

> The most recent IDE
> circuitry that Apple has been doing *does* support many of these modes. 
> The IDE in the PowerBook 150 was so non-standard that Drive Setup cannot
> reformat that drive, a seperate drive formatting program from Apple is
> needed just for that computer.  Last I heard, Apple wouldn't release their
> specs on IDE to FWB Software so they could optimize their drivers.  I once
> tried the FWB drivers, and they were as much as 50% slower than Apple's!
> I don't think IDE is going to be an easy thing to support.  But I'd love
> someone to prove me wrong. :)

Obviously, the PowerBooks are different matters, but the Q630 and
clones are probably not going to be all that weird.  I'm not suggesting
that I'm up to the task, but I don't think that IDE will be as hard to
support as it seems to be being assumed it will be...

	-Seth Miller