[comp.sys.next] Burn-in fears

oneill@fornax.UUCP (Richard Oneill) (02/22/91)

Some of our older NeXT machines have an after-image of the loginwindow
burned into their display. Its faint, but noticeable. I don't know whether
this was caused by behavour which is no longer exhibited by v2.0, but I have
noticed that at our site, running v2.0, loginwindow screens stay at "normal
intensity" for quite a while after logout before dimming to "reduced
intensity". Is there some way to

	a) Reduce the dimming time for the login window
	b) Switch off the monitor when I want the machine to keep running
	   but I know no one will be using it.
	c) Have the login window appear in slightly different places on
	   the screen each time it is drawn.
	d) Replace the default screen saver with an alternative one.

Thinking about it, has anyone had problems with icons (such as the NeXT
icon) in the dock burning in, and if so is there any way to prevent this
happening.

Or is the burn-in problem imaginary, and sensible monitor brightnesses cause
no chance of problems.

	Richard
--
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please try your call again later. This is a recording | oneill@cs.sfu.ca

garnett@cs.utexas.edu (John William Garnett) (02/23/91)

In article <2171@fornax.UUCP> oneill@fornax.UUCP (Richard O'Neill) writes:
>Some of our older NeXT machines have an after-image of the loginwindow
>burned into their display. Its faint, but noticeable. I don't know whether
>this was caused by behavour which is no longer exhibited by v2.0, but I have
>noticed that at our site, running v2.0, loginwindow screens stay at "normal
>intensity" for quite a while after logout before dimming to "reduced
>intensity". Is there some way to
>
>	a) Reduce the dimming time for the login window

This question came up a while back (a month ago?).  I don't remember that
there was any response giving a way to set the autodim time in such a way
that it affected the machine when no one was logged in.  If you want to
experiment, there is an IOCTL that sets the autodim time (and for that matter
there is an IOCTL that sets the dimming level).  Use "man evs" for more info.

>	b) Switch off the monitor when I want the machine to keep running
>	   but I know no one will be using it.

I too would like a way to be able to do this.  Is there anyway (under
software control) to switch off the monitor power without switching off
the machine?  I'm pretty sure there isn't any documented way :-) but that
hasn't usually stopped people...

>	c) Have the login window appear in slightly different places on
>	   the screen each time it is drawn.

Interesting idea...  You know one thing you could do is write a cron
script that uses the screen dimming IOCTL to run every hour or so
(if no one is logged in then dim the screen all the way) [someone
has already done this, I can dig up the script if you want].  The builtin
autodimmer only dims to 1/4 the current brightness - this doesn't really seem
to be dim enough.  Who knows, you might get burnin even if you have dimness set
to zero (if with dimness 0, you can still see a faint image of the login
window).  Other people have written scripts using pft (think that was it
anyway) to put up a black window covering the entire screen.  Perhaps
a good combination would be to dim the screen all the way and put up the
black window (would this use less power than just putting up the black
window?).

>	d) Replace the default screen saver with an alternative one.
>

There are some screen savers out there in the archives.  Most people
claim to have had problems getting some of them to work.  One called
LockScreen should be ready for 2.0 in a short while assuming I've been
reading the author's posts correctly.

>Thinking about it, has anyone had problems with icons (such as the NeXT
>icon) in the dock burning in, and if so is there any way to prevent this
>happening.

good question :-)  Maybe you could write an icon shuffler that would put
your icons up in a different order each time you logged in!  Boy wouldn't
that add to the learning curve for the environment (laugh).

>
>Or is the burn-in problem imaginary, and sensible monitor brightnesses cause
>no chance of problems.
>

I have seen several posts from people complaining about monitor burn-in...
I doubt the problem is imaginary (in the usual sense of the word).

-- 
John Garnett
                              University of Texas at Austin
garnett@cs.utexas.edu         Department of Computer Science
                              Austin, Texas

bchen@kanga.caltech.edu (Bing-Qing Chen) (02/23/91)

In article <2171@fornax.UUCP> oneill@fornax.UUCP (Richard O'Neill) writes:
>Some of our older NeXT machines have an after-image of the loginwindow
>burned into their display. Its faint, but noticeable. I don't know whether
>this was caused by behavour which is no longer exhibited by v2.0, but I have
>noticed that at our site, running v2.0, loginwindow screens stay at "normal
>intensity" for quite a while after logout before dimming to "reduced
>intensity". Is there some way to
>
>	a) Reduce the dimming time for the login window
 
 The following is a small program that will set the screen brightness to
0 when screen is auto-dimmed and restore to the previous brightness when
screen is reactivated. It will maintain a preset auto-dim time even when
loginwindow is running.

- Bing Chen
bchen@pooh.caltech.edu
--------------------------------------------------------
/*
 * Usage: screensaver <auto-dim minitues>
 * Run when logged into console or run by root
 */
#import <nextdev/evsio.h>
#import <libc.h>

void main( int argc, char **argv)
{
  int nb=0;
  int ob;
  int o_dim,c_dim;
  int ad_time=20400;
  int cad_time;
  int evs=open( "/dev/evs0", O_RDONLY);

  if ( evs == -1 ) {
    perror ("/dev/evs0");
    exit(10);
  }
  if ( argc == 2 ) 
    ad_time = atoi(argv[1])*4080;
  if ( ad_time < 4080 )
    ad_time = 4080;
  ioctl(evs, EVSIOSADT, &ad_time);
  ioctl(evs, EVSIOCADS, &o_dim);
  ioctl(evs, EVSIOCB, &ob);
  while (1) {
    sleep(1);
    ioctl(evs,EVSIOCADS,&c_dim);
    ioctl(evs,EVSIOCADT, &cad_time);
    if ( cad_time != ad_time ) 
      ioctl(evs, EVSIOSADT, &ad_time);
    if ( c_dim != o_dim ) {
      o_dim = c_dim;
      if ( c_dim ) {
	ioctl(evs, EVSIOCB, &ob);
	ioctl(evs, EVSIOSB, &nb);
      }
      else
	ioctl(evs, EVSIOSB, &ob);
    }
  }
  exit(0);
}

datran2 (02/23/91)

In article <1121@lovelady.cs.utexas.edu> garnett@cs.utexas.edu (John William Garnett) writes:
>In article <2171@fornax.UUCP> oneill@fornax.UUCP (Richard O'Neill) writes:
>
>>Thinking about it, has anyone had problems with icons (such as the NeXT
>>icon) in the dock burning in, and if so is there any way to prevent this
>>happening.
>
>good question :-)  Maybe you could write an icon shuffler that would put
>your icons up in a different order each time you logged in!  Boy wouldn't
>that add to the learning curve for the environment (laugh).
>

As a matter of fact I have some slight burn-in on my two year old cube.
I always manually dim the screen at logout, and I have no noticeable
burnin of the login window.  I do have burnin of the icons.  Not the center
of the icons.  My own wetware neural net shuffling of their order seems
to be enough to prevent that, however, the white box around each icon
is now a permanent feature of my screen.

I also use scene (1.0 scene that is) to put up a background pattern of
a "tweed" or "burlap" that I rotate every few days.  This gives some random
burn in of the whole screen (I surmise) that hopefully will help keep
the ageing process a random one.

Steve


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