Screen Blanker V1.2 A Screen Saver Program for OS/2 Purpose: A screen saver is a program which blanks the screen after a specified period of inactivity, in order to prevent patterns from being "burned-in" to the screen. Installation: SCRNBLNK.EXE is a utility in C:\OS2 directory. Create STARTUP.CMD file to activate Screen Blanker each time you reboot your system. The command to do this is: SCRNBLNK /INSTALL You may also wish to add an entry for Screen Blanker to a Desktop Manager program group so you can easily start it at other times. If you want Screen Blanker to be effective in OS/2 DOS sessions, you must also install a device driver. SCRNBLNK.SYS is in C:\ directory. a suitable directory (such as OS2\SYSTEM). Then modify your CONFIG.SYS file to install this driver at startup. You must add a line of the form: DEVICE=C:\SCRNBLNK.SYS (or wherever you installed the file). This line should go before the DEVICE=... lines which install the mouse drivers; otherwise Screen Blanker will be unable to detect mouse activity within the DOS box. Usage: Screen Blanker is normally activated from your STARTUP.CMD file whenever the system is booted, as described under Installation above. Once Screen Blanker has been activated, it will monitor keyboard and mouse activity in all OS/2 sessions. If the specified period elapses without either being used, the screen will be blanked. Optionally, a display of the current date and time will be shown in random positions on the screen. The screen can be restored to its previous state by pressing any key or moving the mouse. Screen Blanker may also be started at other times in any of the usual OS/2 ways -- by selecting it from the File System, by an entry in a Start Programs menu, or by entering the command SCRNBLNK from a command- line window. When Screen Blanker is started it normally displays a dialog box that allows you to set some options. The command line parameter /INSTALL used at startup suppresses this dialog box and uses default or previously set values. Page 3 If Screen Blanker is already active when it is started, the new copy communicates with the previous copy to change the options in effect. The Remove button in the dialog box can be used to terminate a previously- activated screen blanker. The /NOCLOSE option may be specified when Screen Blanker is started to prevent it being removed. If the Screen Blanker device driver has been installed, Screen Blanker will also blank the screen while the DOS Compatibility mode session is in control of the screen. Alternatively, a separate DOS screen blanker may be used in the DOS compatibility session. Command Line Options: The following options may be specified on the command line when Screen Blanker is run: /INSTALL This is normally used when Screen Blanker is run from a STARTUP.CMD file. It bypasses the dialog box popup, and installs the program with whatever options have been previous set up. /NOCLOSE This option prevents the Screen Blanker from being removed from memory, and also prevents changing most of its options. If Screen Blanker is run from a STARTUP.CMD file with this option, the only way to remove it is to remove the command from STARTUP.CMD and reboot the system. Dialog Box Options: The Screen Blanker dialog box allows setting various options. The "PM Session", "DOS Session", and "Non-PM Sessions" checkboxes allow you to control when Screen Blanker is active. By default it is active in all sessions. If you remove the check from "PM Sessions", blanking will not be active in the PM session. Blanking for the DOS session will only be possible if the Screen Blanker device driver has been installed. Page 4 The time interval at which blanking should occur may be entered in the indicated place. The default is five minutes. The "Show clock" check box can be used to control whether the time and date are displayed during "blanked" periods. If "Show clock" is selected, then the "Colors" pushbutton can be used to adjust the colors used in the time/date display. When this pushbutton is selected a second dialog box pops up containing scroll bars that are used to select the colors. If the "Save settings" check box is selected, then your preferences for the other options will be saved in the system OS2.INI file, and will be applied automatically whenever the Screen Blanker is subsequently started. Caveats: (1) Screen Blanker uses the OS/2 VioPopUp service to blank the screen. OS/2 limits use of this function to one program (session) at a time. This means that if a running program has taken over the screen by "popping up", Screen Blanker will be unable to blank the screen. It also means that a running program that wants to use the "popup" while the screen is blanked will be unable to do so. Most programs that use this function appear to wait for the screen to be available, so in practice this doesn't seem to be a serious problem. (2) Some levels of OS/2 version 1.2 contain a bug in VioPopUp which results in a "Protection Violation" (Message SYS1943) if the program is removed (by selecting the Remove option). This occurs only if it has blanked the screen one or more times before being removed. This error arises a few seconds after the program has terminated and appears to be beyond my control. It is apparently harmless, and has been corrected in recent levels of OS/2 1.2.