Path: utzoo!utgpu!cunews!cognos!geovision!gd
From: gd@geovision.gvc.com (Gord Deinstadt)
Newsgroups: comp.arch
Subject: Re: Dynamic Display Architecture
Message-ID: <1503@geovision.gvc.com>
Date: 18 Apr 91 15:43:27 GMT
References: <1991Apr15.200955.3438@waikato.ac.nz> <3340@crdos1.crd.ge.COM> <20670@cbmvax.commodore.com> <1991Apr17.051746.15592@sbcs.sunysb.edu>
Organization: GeoVision Corp., Ottawa, Ontario
Lines: 27

jallen@libserv1.ic.sunysb.edu (Joseph Allen) writes:

>I had an idea for a hardware windowing circuit once which was very simple and
>which would eliminate most of the problems windows have today.  All you do is
>break up the screen into small (maybe character sized) blocks.  Then for each
>block you have a pointer to where in memory the actual data is.  It's really as
>simple as normal character refresh memory,  but with no font chip and with
>wider (32-bits instead of 8) refresh memory.

Hey!  That's my idea! :-)

>So.. has anyone used/seen/proposed something like this?  Why are all modern
>screens simple flat Mac-like clones (I suppose portability is one issue)?

I even prototyped the code.  WITHOUT hardware support, just implementing this
in software, you get a really fast windowing system because there are no
shifts in your display update - just block moves.  And it is dead easy to
figure out which pieces of the screen you have to update.  The most difficult
part is mapping pixel coordinates to memory locations - so line drawing slows
down 10 to 20%.  But it made windowing useable on a 4.77 MHz PC.  I never got
a chance to use it in a product, alas.

>--
That's my .sig lead-in too!  Are you sure you aren't me?-)
--
Gord Deinstadt  gdeinstadt@geovision.UUCP
Ask me about my fast polygon fill, ideally suited for hardware.