> >Also, it's worth noting that those chips don't live directly on the 
> >KFTIA.  They're actually on a PCI bus, which sits on some sort of 
> >bridge.  I'm not certain, but that particular PCI instance may be one of 
> >the (multiple) primary PCIs on the 8200; the KFTIA holds 2 SCSI busses, 
> >and 2 Tulips (21140s, I think), and one "hose" (which, on the particular 
> >8200 you're working on, connects to a PCI bus, which in turn bridges to 
> >EISA).

The KFTIA includes an integrated PCI subsystem.  It uses the same host bridge
chips as the external PCI subsystem (DWPLA or DWLPB).  Electrically, there are 
two PCI busses, each controlled by a bridge chip.  But the two chips work
in tandem to create the appearance of 1 logical PCI bus (the CPU sees a single 
PCI address space).  The logical PCI contains 4 ISP1020 chips, two Tulips (the 
10Mb/s variety...is that a 21040?), and a PCI mezzanine slot normally used for
an FDDI adapter (DEFPA).  Also there is a non-standard connector used for
a PCI NVRAM card (for Prestoserve disk acceleration).

The external PCI subsystem  (DWLPx) uses 3 host bridge chips to
create a logical PCI with 12 slots.  The basic I/O connection to the
system bus is a "hose".  The KFTIA has one real hose and one "logical" hose 
that connects to the onboard PCI.  You can probe the host bridge chips to see 
how many are present and use the same code to handle a KFTIA or a DWLPx.
 
> >
> > > It's also possible I can ignore these ISP SCSI busses for the moment,
> > > shove an Adaptec 2940 or an NCR script engine PCI card into a PCI slot
> > > and boot off of that (yes, I probably won't get very far past that anyway-
> > > but that's what I'm starting to work on...)

If you want to use a different SCSI controller (on an external PCI) the NCR 
53C810 chip is known to work on the hardware.  Performance may not be optimal 
though because it's a long way up to main memory when doing script accesses.

Good luck.

	/gary


Gary L. Grebus		Home:  glg@k8lt.ampr.org
Brookline, NH          Work:  grebus@zk3.dec.com