VIDSLEEP (14/11/1995)
(c)1995, TmutZ Software, Levien van Zon

Contact:
lvzon@bio.vu.nl or levjenno@dds.nl
http://huizen.dds.nl/~levjenno/

Changes: 04/11/1997 - GEM version now locks keyboard control.

Machine: Falcon 030 or machines with a Falcon-compatible video system
This program does not work with the old ST compatible modes on the Falcon.

I lost the original docs when my account sudenly vanished, so
here's some new ones...

WARNING: THIS PROGRAM *MIGHT* DAMAGE SOME MONITORS!!!
I therefore take NO responsability for any damage done by this
to your hardware or software! This program comes TOTALLY WITHOUT
WARRANTY. And if your monitor suddenly blows up, please do
let me know so I can warn others :-)

I wrote this little utility back in 1995, when I had just bought an
SVGA monitor for my Falcon. This monitor had so called EPS Power Saving
capabilities, which allow it to switch into an sleep or standby mode
when your videocard tells it to. Unfortunately my Falcon isn't fitted
with a PC videocard, so I had to think of another way to kick
the thing to sleep.

The solution came in the form of a screensaver called, er...,
wait a sec...TurboBlanker, which could take advantage of power saving
features by, as I discovered with a little help from SysMon, switching
the vertical sync of the videosubsystem to external, thereby
actually stopping vertical video synchronisation. This caused my
monitor to switch into standby mode after a few seconds.
In addition, switching off the video updates should reduce bus
load a little and thus increase processing speed, although I doubt
one would actually notice the increase.

Knowing this it was easy to write a little program to do this myself.
There are two versions, both source codes are included in vidsleep.c.
The first version (vidsleep.prg) is for use in a (multitasking) GEM
environment, using AES calls to wait for a keypress. The second version,
vidsleep.tos, is for use with single tasking environments or a shell.
It uses GEMDOS for keypress-checking and was written in assembly,
making it smaller than the GEM version.

Vidsleep is really simple to use: just run it. Your screen should go
blank and if all goes well your monitor should switch itself into
standby after a few seconds. To turn the monitor back on, just hit
a key.

If you use a multitasking OS, everything should just keep running
normally in the background when the monitor is off.
Well, except maybe programs that wait for a Vertical Blank (VBL)
(because the VBL has gone :-).

I myself have installed the GEMDOS version in my shell PATH and
assigned a desktop function key to the GEM version, so I can
switch off my monitor with the press of a key or by typing a simple
command. In addition to Vidsleep I also use sleep.tos, which is a
utility to switch off the DSP, thereby reducing Falcon power usage
and heat production. This little program can be obtained from most
Atari FTP sites (Falcon utility section). If you can't find it, mail me.

I should really do something like: alias sleep="dspsleep ; vidsleep"
to have fast shell access to both sleep commands, but I'm allergic
to comfort. :-)

Please beware! Fiddling with video sync rates is always risky!
I have used this program without problems for two years on my
Falcon 030 with a cheap Escom SVGA monitor, but I can't guarantee
that it'll work with your configuration.
You will at least need a (S)VGA monitor with EPS power saving
capabilities. You probably shouldn't try this with a TV. ;-)

You may freely copy and use this program and its sourcecode.

In the future I might also release a little utility to switch
off (SCSI) harddisks, just to make things complete.
Have fun!

    -=El Vjenno di Theemuts

WARNING: THIS PROGRAM *MIGHT* DAMAGE SOME MONITORS!!!
I therefore take NO responsability for any damage done by this
to your hardware or software! This program comes WITHOUT WARRANTY.

