14 Oct
2012
14 Oct
'12
12:22 p.m.
On 14/10/12 2:40 PM, Dave McGuire wrote:
On 10/14/2012 01:21 PM, Toby Thain wrote:
Ah yes, silly me. It's a while since I've been looking at DEC stuff, but
I seem to have found motivation again.. :)
When I contemplated this project, I was thinking
of MSCP. But the other
day looking at one of my MicroVAX IIs (not Unibus of course) with an
idle KDA50, I wondered why people don't create faux-disks that emulate
the SDI interface. Not the same solution by any means, but are the SDI
controllers at least more common in QBus and Unibus setups?
That would be great, but it would take a LOT of work. SDI is a fairly
complex interface at the electrical level; there's a good bit of analog
magic involved.
Or, if recreating the controller rather than just
an SDI disk, most
likely it would be simpler to emulate the KDA/UDA than MSCP?
MSCP is the system<->controller interface, so these are the same
thing. (remember DEC built a lot of different MSCP drives with
completely different physical/electrical interfaces)
But emulating MSCP at the register and command level is still a lot of
work. It has been done by an individual, ...
This guy http://www.mscpscsi.com/ ? I studied the MSCP spec and as much
as I could find out about it, but it's the undocumented stuff that
worries me. I expect one would be spending some time with O/S sources.
Also, no hablo analog and digital electronics: That part was to be a
friend's domain. We looked at microcontroller and FPGA possibilities.
--Toby
-Dave