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1995-06-05
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11KB
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VESA DPMS screen saver
──────────────────────
OVERVIEW
DpmSave is a DOS screen saver for 'green' (power-saving) monitors
that conform to the VESA DPMS standard.
This screen saver does not simply blank the screen, it will
switch your computer monitor into suspend (power-saving) mode!
REQUIREMENTS
You need three things:
- PC compatible computer running MS-DOS
- computer monitor that conforms to the VESA DPMS standard
- VGA compatible graphics card
Optional:
- XMS memory and a driver program for upper memory blocks.
If this is available, DpmSave can load itself into an
upper memory block, using none of the main 640kB memory.
WARNING
DPMS (Display Power Management Signaling) signals the monitor to go to
suspend or sleep mode by switching off one or both sync signals.
THIS MISSING OF SYNC SIGNALS WILL CAUSE *PERMANENT* *DAMAGE*
TO SEVERAL OF THE OLDER COMPUTER MONITORS THAT DO NOT SUPPORT DPMS!
The program DpmSave can not detect whether or not your monitor does
support DPMS. It's your responsibility to find out and not use this
program if your monitor does not support DPMS. Please consult the
manual of your monitor or ask the dealer or manufacturer. If DPMS is
not mentioned in the manual, then the monitor most probably does not
support it.
If you hear a high pitch sound from your monitor when DpmSave
activates or the picture gets squeezed or scrambled, switch the
monitor off immediately! However note that absence of these warning
signals does not tell that your monitor does support DPMS. You can not
try it, you must look it up.
COPYRIGHT and COST
This program and its documentation are fully copyrighted
(c) Copyright 1995 by Klaus Hartnegg, Kleist-street 7,
D-79331 Teningen, Germany.
All rights reserved except as stated below:
Disclaimer: It's almost impossible to write any non-trivial computer
program that does not have some bugs. You use this program entirely on
your own risk. I may not be held liable for any damage. If you don't
like this, don't use it at all.
You might COPY and DISTRIBUTE this program and documentation if both
are UNMODIFIED and distributed together and it's not distributed as
part of or addon to a commercial program.
You might USE this version of DpmSave FREE OF CHARGE.
QUICK START
This section is for experienced users only. Please skip this
if you want to know more about the program before trying it.
1. Make sure that your computer meets all requirements mentioned above,
especially the monitor must conform to the DPMS standard!
2. Execute the command 'DPMSAVE t30s' and wait 20 seconds without
pressing any keys. You should now hear several short beeps.
After another 10 seconds the screen should become blank and
your monitor should switch to suspend mode.
IF IT DOESN'T WORK, PRESS RESET TO REBOOT YOUR PC!
3. If it did work: reboot to get rid of the trial version, then
execute the command 'DPMSAVE t10 umb klr' to install it with more
useful options (activate after 10 minutes, load into upper memory,
define hotkey left+right shift key).
DESCRIPTION
DpmSave monitors all keyboard input. Whenever no key was pressed for a
certain time, it will switch off the vertical sync signal. This causes
a VESA DPMS monitor to go to suspend mode.
DpmSave will issue several short beeps 10 seconds before activation.
If you hear this and don't want it do activate right now, press
any key to restart the counter.
Once DpmSave is activated, it continues to monitor the keyboard.
Any further keypress will cause the program to switch the computer
monitor back on.
All programs should continue running while DpmSave is activated.
DpmSave will not activate while Microsoft Windows is running.
Whenever it wants to activate, it tests for presence of Windows.
If it is found, the time counter is reset. See the section
about LIMITATIONS below for more informations.
INSTALLATION
To install DpmSave, you must specify the time after that power saving
should be activated. If you specify no time, the program will not stay
resident, but display its online help.
Syntax: DpmSave [tX[s]] [umb] [kXY]
Options: tX install and activate after X minutes
tXs install and activate after X seconds
umb load into upper memory if available
kXY define hotkey
Example: DpmSave t10 umb klr
To have DpmSave started automatically each time the computer is switched
on, include the above command in the file C:\AUTOEXEC.BAT
IMPORTANT NOTE:
You should choose an activation time that does not cause the monitor
to be switched on and off to often because this can shorten the lifetime
of the monitor. Power-Saving should be activated only a few times per
day and it should usually not be deactivated shortly after activation.
The manual of you monitor should define safe limits for this.
HOTKEY:
The power saving can optionally be activated by pressing a hotkey.
When this key is pressed, power saving will be immediately be
activated without waiting for the activation time to pass.
To enable this feature, a hotkey must be specified when installing
DpmSave.
The hotkey is a combination of two, three or four of the special keys
Alt, Ctrl, Left-Shift, Right-Shift pressed simultaneously.
To define a hotkey, use the option kXY, where X and Y are keys from
the following table:
A: Left Alt
C: Left Ctrl
L: Left Shift
R: Right Shift
Example: to use Alt+Ctrl as hotkey, specify the option KAC.
You could use the command line: DpmSave t10 umb kac
Then whenever you press the Alt and Control-Key together,
the power saving will be immediately activated.
MEMORY USAGE
This is a TSR (terminate and stay resident) program. This means that
part of it will stay resident in memory.
I have made every effort to make the memory requirement as small as
possible. The result is one of the smallest TSR programs that I have
ever seen: the memory-resident part occupies only 416 bytes (plus 16
Bytes for a memory control block of DOS). No, that's not a typo,
it really needs only four-hundred-and-sixteen bytes!!
Additionally DpmSave can load itself into an upper memory block
thus using absolutely none of the lower 640kB of memory.
DO YOU WANT TO BE ABLE TO WRITE SUCH TSR PROGRAMS YOURSELF
USING TURBO PASCAL? PLEASE CONTACT ME FOR INFORMATIONS ABOUT
MY TSR DEVELOPER TOOLKIT!
Loading DpmSave into upper memory should be done with the 'umb'
option of the program, not with the loadhigh-command of a memory
manager. With a memory manager about 17000 bytes of upper memory
are required during installation. If this amount is not available,
loading will fail. The built in umb-installation works even if
only 432 Bytes are available.
If you load DpmSave low (i.e. not into upper memory), DOS will
automatically allocate additional memory for a copy of all environment
variables. DpmSave will release this memory. This creates a memory
hole. This memory will be recycled if another program is loaded that
needs the same amount for its environment. Otherwise the hole stays
empty.
Hint: You can save memory by installing TSR programs before setting
environment variables.
LIMITATIONS
DpmSave currently monitors only keyboard input, no mouse usage.
DpmSave will not activate while Microsoft Windows is running
because inside Windows it cannot detect keyboard input. Windows
stops all memory resident programs that intercept the keyboard
interrupt. If somebody knows how to change this, please tell me!
Removing DpmSave from memory is currently not supported but it's
possible using third party software (mark,release and my freeumb).
Please forgive my poor english, it's not my native language!
KNOWN BUGS
If the display mode changes while the monitor is in power-saving mode
(for example the computer switches into graphics mode), then the mode
might be disturbed when DpmSave de-activates. Use the DOS command
MODE CO80 to reset the display.
Some monitors seem to like better if the other sync signal
is switched off. I will try to offer both in future versions.
If you find another bug or problem, or have suggestions, please
write me an e-mail to my Internet address below.
REVISION HISTORY
v1.0 23-Apr-95
first published version
v1.1 02-May-95
oops: beep forgot to save cx-register, sometimes caused reboot
command line syntax changed
hotkey
load itself into XMS upper memory block
v1.2 13-May-95
needs less memory in upper memory block
v1.3 27-May-95
load itself into DOS 5+ upper memory block
v1.3a docs updated
FUTURE PLANS
optionally require password for deactivation (see my program KeyLock)
do also switch off hard disks (modern IDE and almost all SCSI disks)
change parameters without reinstallation
optionally load into high memory area instead of upper memory block
work inside Microsoft Windows (anybody interested? can anyone help?)
monitor mouse movements and mouse keys (anybody interested?)
These will likely be implemented only if I receive enough feedback.
Further suggestions, comments etc. are welcome.
LEGAL STUFF
All trademarks mentioned in this document are trademarks or registered
trademarks of their respective companies and are hereby acknowledged.
Turbo Pascal is a great Pascal Compiler from Borland. MS-DOS and
MS-Windows are from Microsoft Corp. VGA, VESA and DPMS are likely
registered too. VGA was developped by IBM. VESA is the Video
Electronic Standard Association. DPMS is the Display Power Management
Signalling standard defined by the VESA. Some trademarks may be
missing in this list; this does not mean that they are not protected,
I just forgot to mention them. If I made other mistakes, please
forgive me - I'm not a lawyer, just a programmer.
AUTHOR
Klaus Hartnegg
Kleist-Strasse 7
D-79331 Teningen
Germany
Internet e-mail:
hartnegg@einstein.freinet.de (home machine)
hartnegg@sun2.ruf.uni-freiburg.de (university)