Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!deimos.cis.ksu.edu!uxc!iuvax!watmath!mks!wheels
From: wheels@mks.UUCP (Gerry Wheeler)
Newsgroups: comp.sys.atari.st
Subject: Re: screen savers (why so big?!)
Summary: can't blank mono screen
Message-ID: <924@mks.UUCP>
Date: 11 May 89 14:39:27 GMT
References: <8905110734.AA12784@ucbvax.Berkeley.EDU>
Organization: Mortice Kern Systems, Waterloo, Ont.
Lines: 17

In article <8905110734.AA12784@ucbvax.Berkeley.EDU>, TK0GRM1@NIU.BITNET (Gordon Meyer) writes:
> I can't fathom why they all want to grab that extra 32K of RAM
> to blank the screen.  Isn't it enough to just zero out the pallet
> and then restore it when it comes time to "unblank"?

This works fine for color systems, but not monochrome.  In the
monochrome system, one bit in the pallette controls whether the video
should be normal or inverted (I guess it is XORed with the video), but
there is no way to make it all black.  I guess that was easier than
using the pallette as they do in color, but it seems unfortunate.  If
they had used pallette entries 0 and 1, then you could have written zero
to both of them and blanked the screen easily. 
-- 
     Gerry Wheeler                           Phone: (519)884-2251
Mortice Kern Systems Inc.               UUCP: uunet!watmath!mks!wheels
   35 King St. North                             BIX: join mks
Waterloo, Ontario  N2J 2W9                  CompuServe: 73260,1043