ID:WS Writing Directly to the Screen
Quarterdeck Technical Note #109
by Dan Sallitt

Q: 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's and QRAM's LOADHI program, there is no reliable way
to determine how much memory an application needs to run other than
by 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 a 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's /GS (get size) parameter, discussed in the QEMM and 
QRAM manuals, you can get an accurate estimate of how much memory 
a program takes. After you finish running the program with LOADHI, 
two numbers are returned: the first is how much memory the program 
took to load and initialize, and the second is the amount of 
memory the program permanently retained.