new disk controllers for DEC platforms (was Re: Q-bus to CF)

[Douglas Taylor]

Why can't the driver(s) for RAM disks be used?  Then the hardware 
interface might be a whole lot simpler, just make the IDE drive look 
like an extended section of memory.

At 11:16 AM 3/2/2008, you wrote:
>On Sun, Mar 02, 2008 at 07:18:51AM -0800, Bob Armstrong wrote:
> > > Ethan Dicks (ethan.dicks at usap.gov) wrote:
> > >
> > >>On Sat, Mar 01, 2008 at 08:35:14PM -0500, Charles H Dickman wrote:
> > >>...
> > >> Software development for a 20 year old OS is not easy.
> > >
> > >And in the case of the PDP-11, several 20-year-old OSes, or in the case
> > >of the VAX, a few old OSes, of many versions.
> >
> >   All true, although it might not be as bad as it sounds.  There are a lot
> > of people on this list, and some of them used old DEC computers and
> > operating systems.  Some of them might already know how to write a driver
> > for one of these OSes - get a group of them together and you'll 
> have all the
> > old OSes covered.
>
>True, but there are a lot of dusty neurons to polish before much progress
>could be made.  I haven't written a device driver for DEC hardware in
>over 15 years (I've worked on Ultrix, and VMS 4.x and VMS 5.x, myself).
>
> > ... the first thing you should do is
> > hack up simh to include emulation of your proposed new "RQATA" interface
> > card; then you could start writing drivers before the hardware was even
> > done, and simh is a great tool for debugging the driver software.
>
>That's an excellent suggestion (and I say that having helped Bob Supnik
>debug one of _his_ drivers long ago).
>
> >   OTOH, the SBC6120 was sort of my experiment in open source old computer
> > development.  I always hoped people would expand and add to it, both in
> > hardware and software, but for the most part that never really happened.
> > Most people wanted to buy a turnkey system that they could plug 
> in, turn on,
> > and start using it - people seem to have jobs, families and real lives and
> > just don't have the time to do a lot of development.
>
> >From my own standpoint, especially since I have an IOB6120 and FP6120,
>it does pretty much everything I'd want it to do.  About the only feature
>I can think of off the top of my head would be to jimmy the IOB6120
>FPGA firmware to be able to talk to a real RX01/RX02 hanging off of the
>I/O pins (with suitable line drivers/receivers, of course).  I'd probably
>only want that to be able to image disks, anyway, though.  Out of the box,
>the SBC6120 boots up OS/8 and that works for most of what I'd do with a
>"real" PDP-8 anyway - boot it up, play a few games, and marvel at what's
>going on under the hood.
>
>In terms of software dev, folks can just as easily fire up simh and work
>on software there.  I always thought the appeal of the SBC6120 was to
>have a real 12-bit machine in ones hands, not the developement aspect of it.
>
>-ethan
>
>--
>Ethan Dicks, A-333-S     Current South Pole Weather at  2-Mar-2008 at 15:49 Z
>South Pole Station
>PSC 468 Box 400       Temp  -52.8 F (-47.1 C)   Windchill   -87.4 F (-66.3 C)
>APO AP 96598          Wind   13.4 kts Grid 12   Barometer 685.9 mb (10406 ft)
>
>Ethan.Dicks at usap.gov            http://penguincentral.com/penguincentral.html