Multiple color screens

[Doug Evans <DE%phoenix.sch.symbolics.com@RELAY.CS.NET>]

    Date: Fri, 10 Mar 89 00:36 PST
    From: Gumby@MCC.COM (David Vinayak Wallace)

    Has anyone tried having multiple color screens on one machine (i.e. more
    than one color board; I don't mean making more than one screen on the
    same piece of hardware).

Yup ... This really works ... with some precautions.  Obviously, you can't
do this in 3640 lisp machines ... no slots available.  Things are better
but tight in a 3650.  You can plug alot of stuff into a 3670 though.

1. You can have two different standard color systems in any one Lisp
   machine.  If you need more than two color screens, we would have to
   put in an Engineering Action Request while you light a fire under the
   salespeople and/or marketing people there.

   Color memory for standard color hardware is hardwired into virtual
   board slots.  Correspondingly, there are two flavors of color
   controlers available: one that maps color memory into slots 16-19 and
   one that maps color memory into slots 20-23.  Changing a color
   controller board from one flavor to another requires an ID PROM
   change and a MAP PAL change (two chips).  Such things are available
   from the guys in the Austin office (for you, Gumby) or from your
   local Symbolics service rep (for the rest of you).

2. You should be able to have any number of CAD color systems (at least
   until you run out of slots).

3. The above two mix such that you can have two different standard color
   systems plus any number of CAD color systems.  I believe things work
   best when the CAD is plugged into a lower slot than the color systems.

Another problem you will run into is a shortage of virtual board slots.
Both 3650s and 3670s have 32 virtual board slots available.  Usages:

 > 3650 Processor boards and 3670 Datapath boards use 1 slot (always slot 31)  

 > 3650/3670 IO boards use 1 slot

 > 512KWord memory boards use 1 slot

 > 1MWord memory boards use 4 slots

 > 1MWord SLB memory boards use 2 slots

 > 2MWord memory boards use 4 slots

 > CAD color systems use 1 slot

 > All standard color systems use 5 slots (any pixel width)

 > Most other optional LBus boards use 1 slot

As you can see, with only 32 slots to play with, things will fill pretty
quickly.

I do know for sure that a two color system configuration works and that
a single CAD system with a single color system configuration works.
Beyond that, at the moment, more experimentation will be needed.  Please
call the Graphics support number for more information.