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- This is the documentation for SCRUTIL.EXE and SCRBLANK.DLL, an
- OS/2 Presentation Manager screen saver for OS/2 1.3 and 2.0.
-
- Kai Uwe Rommel,
-
- Zennerstrasse 1
- D-8000 Muenchen 70
- Germany
-
- Phone: +49 89 723 4101
- Fax: +49 89 723 7889
- email: rommel@informatik.tu-muenchen.de
-
- March 21 1992
-
- ---------------------
-
- 0. Overview
-
- This small program is a screen saver for OS/2 Presentation Manager
- and in addition shows a small window with the current date and
- time and amount of free memory.
-
-
- 1. Installation
-
- Put SCRUTIL.EXE somewhere in your PATH or where you keep your
- utility programs and SCRBLANK.DLL somewhere in your LIBPATH.
-
-
- 2. Start
-
- You can start the program by entering the command "START SCRUTIL"
- but you better put in in some program group (1.3) or folder (2.0).
- You can mark it as "Open when system is started" (1.3) or put a
- shadow of it in the startup folder (2.0).
-
-
- 3. Usage
-
- Initially, the program puts it's window in the upper right screen
- corner, but you can move it whereever you want it. Under 1.3, you
- can then choose "Save" from the desktop manager's "Desktop" menu
- to let it save it's screen position. Under 2.0, the position is
- saved, when the screen saver is terminated or the system is shut
- down.
-
- The window shows the current time and date in the format defined
- in the PM control panel (1.3) or country settings box in the
- system setup folder (2.0) in the first line.
-
- In the second line, the current amount of free memory is shown.
- Under 2.0, this value always shows the total amount of all
- currently unused memory pages.
-
- Under 1.3 it usually shows the largest contiguous segment of
- memory currently available. This does not always represent the
- total amount of free memory, especially not after some time of
- system usage when memory became fragmented (which is not a bad
- thing at all, because the system compacts memory as needed, but
- only when it is needed, not for the free memory display by this
- program). However, there exists an option to let it more precisely
- display available memory, called "bean count" (see below). But use
- this option with care because it can seriously degrade system
- performance and should only be used when really needed (for
- example, whe you want to debug a program and you don't trust it's
- memory usage).
-
- After some period of user inactivity (no keyboard or mouse input)
- the screen is blanked. You can blank the screen immediately by
- moving the mouse pointer into the upper right screen corner and
- you can prevent the screen from beeing blanked by moving the mouse
- pointer into the lower right screen corner.
-
- You can bring up the screen saver's configuration box by double
- clicking on the window.
-
-
- 4. Configuration
-
- The configuration box is different under 1.3 and 2.0. Under both
- systems, it shows a title and copyright and version number and
- three buttons, "Ok", "Cancel", and "Terminate". You of course know
- what the purpose of these buttons is.
-
- Under 2.0, a group of controls are showed to adjust the screen
- saver. You can specify the saver delay time, if it should blank
- your screen at all and which display cards are in your computer.
-
- The possible cards are 8514/A, VGA, EGA and Monochrome. This screen
- saver does not use and Presentation Manager functions to perform
- the screen blanking but rather uses hardware capabilities of the
- display cards to blank the screen. This has the advantage, that no
- screen redraw has to be done when the screen is switched back on.
- In addition, it cannot interfere with running programs (as long as
- they do not change the current screen palette).
-
- But for the screen saver to function properly, you must correctly
- set what kind of display adaptor(s) you have. You can check more
- than one adaptor, if you have a secondary screen attached to your
- computer, for debugging programs, for example. In such cases, the
- screen saver can blank the debug screen too. Possible combinations
- are VGA and Monochrome, 8514/A and VGA or even 8514/A, VGA and
- Monochrome all together.
-
- If you should have problems that your VGA does not get blanked
- properly although you have choosen VGA in the configuration box,
- you can try to choose EGA instead, which should work with all VGA
- cards too.
-
- Under 1.3 the configuration box shows another group of controls
- to let you adjust the free memory display. You can choose bean
- count if you need to (see warning above) and if you enable the
- bean count, you can adjust the minimum size of the segments which
- should be counted for the total free memory and the interval at
- which the total free memory amount should be recalculated.
-
-
- 5. Future enhancements
-
- Perhaps newer display cards can be supported as they become
- available and if I get access to one. For example, I would like
- to hear from XGA users, if the screen saver works with it and
- with which setting (8514/A or VGA).
-