Northstar Horizon

From: allisonp_at_world.std.com <(allisonp_at_world.std.com)>
Date: Tue Nov 2 14:02:10 1999

> > My solution was far more reasonable. Map it <VDM1> at 4000h and set a bit
> > to enable it (small hack). That way it used no TPA space and was still
> > faster than using a TTY. I later set up one of the NS* controllers that
> > way for a full 64k space. Of course I had to write my own drivers but it
> > was pretty trivial.
>
> And hack the RAM board to be disabled when the VDM1 is enabled?

Ah, ever hear of phantom... part of the MDS-A and VDM IO hack was to set
them up to output Phantom, in both cases it was just a jumper required.
The disable was simpler, MDS-A has a rarely used sector interupt enable
latch and the VDM used a bunch of bits for windowshading, something I
considered useless and removed from the board (a few socket level jumpers)
and I had the bit I needed for enable. If they were enabled phantom was
generated, if they were not ram was there.

Allison
Received on Tue Nov 02 1999 - 14:02:10 GMT