

                                     SLEEPER
                                  by Eric Tauck
                                October 25, 1989

     SLEEPER is a memory resident utility that automatically blanks a
     screen after a certain period of keyboard inactivity or upon command
     by the user. This is useful in preventing screen 'burn-in' or hiding
     the contents of the screen from prying eyes.  SLEEPER requires a
     standard IBM PC or compatible computer running PC or MS DOS version
     2.0 or higher and uses about 750 bytes of memory.

     NOTE: there are different versions of SLEEPER for different adapter
     types.  Only run the version of SLEEPER that matches the computer's
     adapter.  See the end of this document for more information on the
     different versions of SLEEPER.

     SLEEPER must be made resident before it can blank the screen
     automatically. This is done by running SLEEPER from the DOS command
     line.  A single numeric parameter may be specified to set the amount
     of time (in seconds) before blanking the screen.  If the parameter is
     absent, SLEEPER will blank the screen after five minutes (300
     seconds).

     Once installed (i.e. made resident), SLEEPER constantly monitors the
     keyboard and system clock.  If no key is pressed for the specified
     amount of time, SLEEPER blanks the screen.  SLEEPER will make the
     screen visible the moment any key is pressed.  The pressed key is NOT
     absorbed by SLEEPER, but is passed through to the system.

     The resident SLEEPER can be controlled by running the SLEEPER program
     or with special keystroke commands.  The keystroke commands will only
     work when an application is expecting keyboard input.  For instance,
     during a long compile, the keyboard commands will not work because
     most compilers don't poll the keyboard.

     If the screen is explicitly blanked (by running SLEEPER with the H
     option or pressing ALT-CTRL-H when resident), it will remain so until
     it is explicitly un-blanked (by running SLEEPER with the V option or
     pressing ALT-CTL-V when resident) or by resetting the timer (by
     running SLEEPER with the R option or pressing ALT-CTRL-R when
     resident).

     The screen can be blanked without installing SLEEPER by running it
     with the H option.  The screen will remain blank until SLEEPER is run
     again using the V option.

     SLEEPER will blank the screen in all text and graphics modes.  When
     the screen is blank, the computer continues to operate normally.  You
     can continue to type commands to an application or DOS, even if you
     are unable see what you're typing.

                        Non-Resident Command Line Options
                        ---------------------------------

     SLEEPER ?

       Display a brief help screen.



     SLEEPER nnn

       Install SLEEPER with a timer value of 1 to 3600 seconds.  If this
       number is absent, SLEEPER will be installed with a value of 300
       seconds (five minutes).  Note that the number 'ticks' are displayed
       upon installation, not seconds.  Ticks occur at about 18.2 per
       second and are what SLEEPER actually uses to measure the passage of
       time.

     SLEEPER H

       Force the screen hidden (i.e. blank).  The screen will remain hidden
       until the screen is forced visible with the V option below.

     SLEEPER V

       Force the screen visible.  Only useful if the screen has been forced
       hidden with the H option above.

                          Resident Command Line Options
                          -----------------------------

     SLEEPER ?

       Display a brief help screen.

     SLEEPER nnn

       Set a new timer value.  The range of legal values is 1 to 3600, the
       same as when installing SLEEPER.  As when installing, the number of
       ticks (not seconds) are displayed.

     SLEEPER H

       Force the screen hidden (i.e. blank).  The timer is disabled and the
       screen remains blank until it is forced visible or the timer is
       reset.

     SLEEPER R

       Reset the timer.  The internal timer is reset as if a key was
       pressed.  If necessary, the timer is restarted and the screen is un-
       blanked.

     SLEEPER T

       Force a timeout.  The internal timer is set so the screen will blank
       after one second.  Once the screen is blanked, it will be un-blanked
       as soon as any key is pressed.

     SLEEPER U

       Uninstall SLEEPER.  This command removes SLEEPER from memory.
     Sometimes
       SLEEPER cannot be removed if another TSR has been installed after
       SLEEPER.



     SLEEPER V

       Force the screen visible.  The timer is disabled and the screen
       remains visible until it is forced hidden or the timer is reset.

                           Resident Keyboard Commands
                           --------------------------

     ALT-CTRL-H

       Force the screen hidden.  Same as SLEEPER H above.

     ALT-CTRL-R

       Reset the timer.  Same as SLEEPER R above.

     ALT-CTRL-T

       Force a timeout.  Same as SLEEPER T above.

     ALT-CTRL-V

       Force the screen visible.  Same as SLEEPER V above.

                                   Usage Notes
                                   -----------

     SLEEPER is usually installed automatically in the AUTOEXEC.BAT file
     when the computer is booted up.

     Controlling SLEEPER from the command line is typically done from batch
     files to modify SLEEPER before loading an application and then to
     restore SLEEPER once the application has terminated.  Since SLEEPER
     cannot detect input from a mouse or joystick, you may want to force
     the screen visible before running an application which primarily uses
     a mouse or joystick for input.

     SLEEPER doesn't work well with all applications, particularly
     applications that are timing or video sensitive (like games for
     instance).  If you think there is a conflict between an application
     and SLEEPER, you can always uninstall SLEEPER before running the
     application and then reinstall SLEEPER once the application has
     terminated.

     SLEEPER monitors the shift keys (SHIFT, ALT, and CTRL) as well as all
     of the 'normal' keys.  A shift key can be used to restore a blanked
     screen without passing a keystroke to the currently executing program.

     Releasing a pressed key has a the same effect as pressing a key, thus
     if a key was being held down when SLEEPER decided to blank the screen,
     the screen will be un-blanked as soon as the key is released.
     Similarly, if you use the forced timeout keystroke command (ALT-CTRL-
     T) and hold the ALT or CTRL keys down for more than one second, the
     screen will be un-blanked as soon as you release either key.



     SLEEPER only works with VGA adapters, however two special versions of
     SLEEPER, SLEEPERE and SLEEPERM, are provided that should work with EGA
     and monochrome adapters respectively.  SLEEPERE blanks the screen by
     setting the palette registers to black.  Because setting the palette
     registers is not an instantaneous operation, keystrokes can be lost
     when blanking or restoring the screen.  Only run the version of
     SLEEPER that matches the computer's adapter, though it should be okay
     to run SLEEPERE on a VGA adapter.

