> It looks like IDE will be the way to go,  Allison has done a good proposal
> here.  Now we need to collect up the data sheets and make them availible so
> that a hardware design could be started.  I would suggest that we stay away

Will that be PIO or DMA? 

I didn't see any definitive answer on that.. Feel free to shout at me
if I missed the obvious somewhere..

Even though I'm not very happy with IDE it can do reasonably well 
in a 1-drive-per-controller setup.

What I'm a bit worried about is the resulting speed from a PIO 
design. What can we expect? VS3100 PIO speeds? 30 Kbyte/sec?

And how much of the VAX'es (precious) CPU cycles will it be
using (wasting?) copying those bits from the drive?

If it's a DMA design I say: go for it! 

DMA does rule out some older IDE drives which either don't support 
DMA at all or are quite broken in that respect. Lots of cruddy 
implementatin in the peecee world..

But as for SCSI..

>From the discussion(s) here I see that SCSI would immediatey
mean 'on-board CPU'. I'm puzzled by that..

If you grab a 5380 derivative (preferrably better ;-) it should 
only need some logic for DMA'ing, but the chip should handle
most of the low-level SCSI stuff itself.

I use PC SCSI controllers (eg. Adaptec 1542 ISA with bus-master
DMA) as a reference here.. These cards (almost) never use an extra
on-board CPU.

Or am I (again) missing something obvious here?

How about a Qbus to PCI bridge ;-)

> from surface mount components if we plan on making bare boards availible to
> users to assemble themselves also while it may not be as steamlined it might
> be better to stick with off the shelf thru hole components rather than
> programible ones like FPGA or some such.  One thing is for sure the simpler
> we make this project the more likely we are to get a board up and running!

For home-building DIP's are the way to go.. Definitely not SMD.. Bad
for your nerves ;-)

							Bye Arno.

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