[Info-vax] vax4000

[John Wallace]

On Oct 13, 7:39 pm, Steven Schweda <sms.antin... at gmail.com> wrote:
> On Oct 13, 8:41 am, koeh... at eisner.nospam.encompasserve.org (Bob
>
> Koehler) wrote:
> > [...]  you may need to design the interface
> >    using analog logic, not digital, [...]
>
>    I'd love to see a reasonable definition of "analog logic".
> My slide rule didn't have True and False on it.  (It _did_
> have a "1", but not a "0", unless you count one on the "L"
> (log) scale.)
>
>    But back to the real question, ...
>
>    A Web search for B400X, R400X, and M9405 should give you
> some idea of the hardware involved.  I doubt that the cables
> were anything special.  I never tried it, but I suspect that
> a (matched) pair of old SCSI cables (preferably shielded?)
> could do the job of connecting this stuff.
>
>    Are your "drv11 cards" actually DRV11-WA cards, or some
> other DRV11 variant(s)?
>
>    Personally, unless I already had all this hardware lying
> around, I'd be looking for some other way to have fun.
> (Something slightly more useful, for example, might be an
> Alpha LR driver which could do input as well as output on a
> parallel port.)

An input-capable LRdriver would be an interesting idea.

DRV11Js used to make relatively undemanding low speed PIO stuff
relatively easy to do.

If I was in these circumstances with the described kit to control, I'd
perhaps look at doing the actual real time stuff on either an FPGA
board or maybe a small ARM (or even PIC) board, depending on the
details. Then you use the VAX to send the required co-ordinates to the
control board, and the VAX does any number crunching, data logging, or
other more general purpose stuff which may be required. But I guess
for some folks that eliminates half the fun!

In days gone by I'd also have happily suggested the marvel that was
VAXeln for the RT stuff but maybe that's a bit niche or overkill for
the hobbyist market, though VAXeln didn't half make it easy to write
sensible applications that could twiddle bits of hardware without
having to understand the joys of VMS in kernel mode.