Michael R Zucca wrote:
> 
> > > 	Lastly, I found a guy who is going to sell me his Q900 for pretty
> > > cheap... what is the current state on this machine? (I'm having trouble
> > > with Netscape, and my lynx on my NetBSD is also suffering from my
> > > file-system woes, or I would look it up on the machine-status page myself
> > > ;-)) 
> > 
> > It's still fairly non-functional at the moment, I believe.  Both of the
> > Q900 and Q950 use the IOP's for ADB and serial port functionality.  While
> > the serial ports might work, the ADB definitely doesn't.  In addition,
> > there might be some issues with the dual SCSI bus on these machines.  I
> > suppose you might be able to get a headless net-booting machine out of it,
> > but it wouldn't probably be very useful right now.
> 
> Actually, Allen's been trying to squeeze some info out of Apple about the
> IOPs and barring that I suppose we could sit down and starting looking at
> code in MacsBug.

Well, I wish him the best of luck...but when I last asked about hardware
information, they said that they no longer distribute that kind of
information to _anyone_ except certain licensed partners, and that they
weren't going to be issuing anymore of this type of license, either.
 
> FYI, the IOPs are actually 6502's linked to their respective devices.
> They handle interrupts and buffering, interrupting the CPU only when
> necessary. They have something like 32k of RAM which is mapped into
> devices space somewhere. So it's sort of nothing like DMA ;-)
> Just wondering if who ever codes the IOP stuff is going to have to
> crack open an old book on 6502 assembly <bleck!>

Ah....it's been a _long_ time...but Apple II's were pretty cool ;-)

> The dual SCSI bus thing shouldn't be too bad. I believe the base address of
> both busses is well known. Just attach the esp driver in two places
> (or is that the problem?) Doesn't the Quadra 700 have two SCSI busses?

No, it doesn't, just one.  I don't think it'll be a real problem either,
but I seem to remember that it didn't quite work "out of the box" the last
time someone tried.

Later.

-- 
Colin Wood                                 cwood@ichips.intel.com
Component Design Engineer - MD6                 Intel Corporation
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I speak only on my own behalf, not for my employer.