Screen Blanker V1.2 A Screen Saver Program for OS/2 Alan Ballard June 12, 1990 Notice: Screen Blanker is (c) copyright 1990 Alan Ballard. It may be used without charge and may be freely distributed as long as it is not modified in any way. It may not be sold, traded, or otherwise disposed of for profit without permission from the author. Disclaimer: This program is offered on an "as-is" basis __________A A __________A A without any guarantee as to correct functioning or fitness for any specific purpose. The author believes this program to work as described, but you use the program entirely at your own risk. The author will not be responsible for any hardware or software damage, loss of data, or incidental or consequential damage that may result from use of the program, whether or not such use is in accordance with the instructions. 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. Hardware and software required: Screen Blanker Version 1.2 requires OS/2 Version 1.1 or 1.2. It should work with either Standard Edition or Extended Edition and with any computer and monitor that are supported by OS/2. The current version (1.2c) has only been tested with OS/2 1.2 SE syslevel XR04020 (the "November Update" version of 1.2 SE). Installation: Copy the file SCRNBLNK.EXE to a directory that is part of your normal OS/2 search path. \OS2 or \OS2\PBIN are good candidates. Copy the file SCRNBLNK.DLL to any directory that is specified in your OS/2 LIBPATH. \OS2\DLL is normally used for DLL's, but any other directory in the LIBPATH is OK. Then, modify your STARTUP.CMD file to activate Screen Blanker each time you reboot your system. The command to do this is: SCRNBLNK /INSTALL Page 2 You may also wish to add an entry for Screen Blanker to the OS/2 1.1 Start Programs menu or a (version 1.2) Desktop Manager program group so you can easily start it at other times. 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. 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. Screen Blanker will not blank the screen while the Dos Compatibility mode session is in control of the screen. A separate Dos screen blanker may be used in the Dos compatibility session. Options The Screen Blanker dialog box allows selecting the time interval at which blanking should occur. The default is five minutes. The "PM Sessions" and "Non-PM Sessions" checkboxes allow you to control when Screen Page 3 Blanker is active. By default it is active in all OS/2 sessions. If you remove the check from "PM Sessions", blanking will not be active in the PM session. This allows you to install one of the fancier Presentation Manager screen blankers that are available, while still using Screen Blanker for non-PM sessions. 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) OS/2 version 1.2 contains 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 errors arises a few seconds after the program has terminated and appears to be beyond my control. It is apparently harmless. Author: Alan Ballard, 3452 West 11th Avenue, Vancouver, Canada, V6R 2J9 Compuserve: 70446,44 Internet: ballard@staff.ucs.ubc.ca