Ok, perhaps some on board intelligence is the way to go. I guess one
possibility is something like a Rabbit Core
(http://www.rabbitsemiconductor.com/). These provide a reasonable number
of I/O lines for interfacing with the bus plus ethernet, 4 serial ports,
1/2 meg of ram and 1/2 meg of flash. Plus they are cheap and I already
have a developers kit!

Being ethernet based should give them good long term support, and flash
programming means the onboard software can be upgraded easily.

Something I think would be worthwile would be to make the I/O mapping
fairly flexible so the option exists to make the device emulate a rage of
existing controllers. Will have to consider whether this over complicates
the design

So my next question, are there any generally available bus drivers for the
QBUS and UNIBUS. I believe the DS8838 was suitable (at least for the QBUS)
but this device is no longer in production. Any suggestions on suitable
alternative devices?

Also, is there a good reference I can read on the DMA side of Qbus and
Unibus. I'm fairly familiar with the PIO side from building my own 8 bit
SBCs in my youth, but I never really got into any DMA magic.

Thanks,
Toby

> From: "Tobias Russell"
>
>>I'd certainly advocate a unix/linux solution on the PC side although

having produced that porting to windows might not be a big issue.
>
> FWIW, I've found that making a PCI device driver continue to work across

various Linux kernel releases is a total nightmare. They make
gratuitous
> changes all along, and nothing is really documented. Well OK there's a

book available but I've found it gives only fleeting enlightment,
everything
> changes two weeks after each edition and you're back where you started.
>
> Only half kidding: how about stand-alone? Over the past 23 years, PC

hardware has maintained vastly better backwards compatibility (for
better
> or worse) than any PC operating system has.
>
> (Yes, a stand-alone version of E11 is in the works.)
>
> I like the idea of an embedded CPU better, since that gives you a stable

place to put the real device driver code (for talking to the CSRs and
DMA system). Then use some bus with a good combination of price, speed,
simplicity, and longevity (hmm, sounds like the anti-Massbus), for
talking
> to the PC side.
>
> John Wilson
> D Bit
> ----------
> To unsubscribe (or subscribe) from (to) this list, send a message to

info-pdp11-request@village.org, with the first line of the message body
being "unsubscribe" or "subscribe", respectively (without the quotes).
>



Tobias Russell
Managing Director
Russell Sharpe Ltd
Tel: 01483 894158
Fax: 01483 898932


----------
To unsubscribe (or subscribe) from (to) this list, send a message to
info-pdp11-request@village.org, with the first line of the message
body being "unsubscribe" or "subscribe", respectively (without the quotes).