[Simh] DMA access to the IO page

[Paul Koning]

> On Sep 5, 2018, at 10:13 PM, Bob Supnik <bob at supnik.org> wrote:
> 
> Apparently, the GT40 does this. So... problems.

FWIW, I've done this too, in college on our 11/20.  That was for a primitive CRT display (an X/Y scope attached to an AD11 (?) D/A converter) which had its data fed to it by DMA from the RC11 system disk.  It was set to write to the D/A data register, with bus address increment inhibit set.  Crude, but it worked.

	paul