Subject: Re: views and pagers
To: David Jones <dej@eecg.toronto.edu>
From: Eduardo E. Horvath eeh@btr.com <eeh@btr.btr.com>
List: amiga-dev
Date: 03/24/1994 14:37:04
On Thu, 24 Mar 1994, David Jones wrote:

> Is the bitmap for /dev/view implmented via a banked device pager?

[ Other questions about paging deleted.]

Banking and paging are orthogonal issues.  The issue of banking came 
about because (from what I have gleaned) Retina cards are built using PC 
VGA controller chips.  These chips are designed for an architecture where 
1MB of video RAM needs to be sandwitched into a 16KB segment of memory 
that was allocated for video display in the original IBM PC.  The frame 
buffer is split up so portions of it can be banked in and out of that 16K.

As far as I know, the frame buffers do not page.  You would suffer from 
some strange display problems if part of your frame buffer was paged out 
and part of an application was paged in on top of it.

The paging you are probably suffering from is probably the X server.  
What it does is interpret commands from client programs and scribble into 
the frame buffers.

=========================================================================
Eduardo Horvath				eeh@btr.com
					..!{decwrl,mips,fernwood}!btr!eeh
	"Trust me, I am cognizant of what I am doing." - Hammeroid


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