🚀 go-pugleaf

In article <1992Nov16.155538.874@infodev.cam.ac.uk>, nec10@cus.cam.ac.uk (N.E. Cole) writes:
> I may be given a DEC Rainbow (10 MB HD) soon, are there any patches about to
> allow me to run DOS later than 2.11 on it and to use the enchanced graphics as
> cga etc???

There is a version of DOS 3.1 customized for the Rainbow, but my
understanding from talking with one of the developers of the
Rainbow adaptations is that it isn't just a `few patches'.  You
can't reasonably start with either the Rainbow DOS 2.11 version
nor with an IBM DOS 3.1 version and get a useable system without
a LOT of work, and that assumes that you have the _sources_ to
the DOS [!!].

Unfortunately I don't know where you can get DOS 3.1 for the
Rainbow these days.  At one time you could get it `under the
table' from DEC, and then when DEC dropped the Rainbow they 
licensed the rights to the Rainbow adaptations for DOS 3.1 to
Suitable Solutions, which is now out of the Rainbow business.
It's possible that one or another of the Rainbow user's groups
has picked it up, but I've lost track of them.

As for using the enhanced graphics as CGA, forget it.  It is
possible to run many text-mode IBM-PC applications that write
directly to the PC screen memory on the Rainbow if you have
the `Code Blue' software product, which allocates a frame of
memory at the same address as the IBM video memory and copies
it back and forth;  but the graphics adapters are so far apart
that it's just not practical to write such an intercept program.
(It's not just a question of the memory format and the CPU
cycles;  many PC graphics programs write to the CRT controller
chip, which the Rainbow doesn't have in a compatible form, and
the 8088 CPU doesn't have protected mode so there is no way to
virtualize the references to the hardware).

There are a few graphics programs floating around for the Rainbow,
and there is also a version of Microsoft Windows 3.0 for the
Rainbow (obviously Windows 3.1 isn't possible because it requires
protected mode).  It only runs in monochrome (2-color), but it
has more resolution than the CGA adapter so it isn't quite as
bad as running Windows on a CGA.  It _is_ worthwhile to find one
of the Rainbow 286 accelerator cards (Turbow 286 was one of them,
sold by Suitable Solutions) if you run Windows since it takes
just a bit of the CPU :-).

Unfortunately, since the Rainbow is an orphan machine at this
point, there's not any one place that you can go to get any of
this stuff.  You may be able to find one or another of these
things at one of the used DEC equipment dealers, or at a swap
meet or user group (or from someone on the net or a BBS), but
it's going to take some digging.  If you get the machine I may
be able to pull together some Rainbow software to send you, but
we don't have any Rainbow hardware for sale.

Good luck,

Bruce C. Wright

nec10@cus.cam.ac.uk (N.E. Cole) writes:
> I may be given a DEC Rainbow (10 MB HD) soon, are there any patches about to
> allow me to run DOS later than 2.11 on it and to use the enchanced graphics as
> cga etc???
> 
> Nick