Xenix driver for Univision 1024 video board

[David L. Markowitz]

I am in the process of writing a driver for a Univision 1024 frame buffer,
and I have a few questions.

First the details.  I have ten years of Unix experience, and have written
many drivers, but I've never worked with Xenix or DOS much.  My background
is Vax/68000/Sparc and VME based, not Intel and AT bus based.  The hardware:

Standard stuff:
	SCO Xenix 2.3.2
	Micronix 20MHz 386 + Cache
	2 MB RAM
	80 MB Hard Disk
	Monochrome Video Board

I am adding:
	Univision 1024x1024 frame buffer with VSB bus
	Tecon DVX1024 Frame Grabber with VSB bus

I already have the Tecon mostly working (it won't interrupt, though).

I need to map in 64K chunks of the video memory on the AT bus.
The board includes registers to set up which piece of video RAM
is mapped to the bus, but I don't know how to interpret Intel-style
addresses like C400:0200 within a driver.

I do not need to use this as my console device, nor does it need
to interface to the standard video boards data structures (although
that would be nice).  I really just want to use it as an alternate
stand-alone display, while also having the monochrome display hooked up.

Now, the questions:

1) Has anyone already written this?  How about other memory mapped video
   board drivers?  Are there any floating around in source form that
   people wouldn't mind letting me look at?

2) How do I access the bus at such an address from Xenix?

3) Is there a good manual/book somewhere on how Xenix deals with the
   fractured concepts of the AT bus.  (Or, "Gee - a real computer!  Too
   bad it can't talk to the rest of the world very well...")  (When
   Sun designed their 386i machines, they had to figure out how to
   co-exist with the AT bus.  Their solution?  "We don't use it!")

4) Am I crazy?

Please reply by mail - I will summarize if there is enough interest.

	David L. Markowitz
	Genisco Technology Corporation
	dav at genisco
-- 
	David L. Markowitz
	Genisco Technology Corporation
	dav at genisco