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- ID:WS Writing Directly to the Screen
- Quarterdeck Technical Note
- by Dan Sallitt
-
- How can I tell if my program writes directly to the screen?
- Or how much memory it needs?
-
- To tell if an application is writing directly to the video
- hardware inside DESQview, make the following changes in the
- application's Change a Program menu:
-
- 1) Set "Writes Text Directly to Screen" to N;
-
- 2) Set "Virtualize Text/Graphics" to N;
-
- 3) On the Advanced Options screen, blank out the following four
- fields in the "Window Position" section: Starting Height,
- Starting Width, Starting Row, and Starting Column. Put blanks in
- these fields, not zeros.
-
- When these changes have been made, open the program. DESQview
- will place a small window border on the screen; if the program
- comes up and stays within the small window border, it does not
- write directly to the screen. If it blows away the window border
- and takes the full screen, it writes directly to the hardware.
-
- Without QEMM 5.0's and QRAM's Loadhi program, there is no reliable way
- to determine how much memory an application needs to run other than
- trial and error. You can make a reasonable guess by adding together the
- size of the .COM or .EXE file that starts the program and the size of
- its biggest overlay, but the program's data storage needs are difficult
- to predict. The time-honored method for determining the correct memory
- size for a window is to start by giving the window an excessive amount
- of memory, then reducing that figure a bit at a time until the program
- starts malfunctioning.
-
- With Loadhi/GS:filename, discussed in the QEMM and QRAM manuals, you can
- get an accurate estimate of how much memory a program takes. GS stands
- for Get Size, and filename stands for the name of the file (and the
- correct path, of course). After running the program with Loadhi, two
- numbers are returned: The first is how much memory the program took to
- load and initialize, the second is the amount of memory the program
- permanently retained.
-