/FHQ23: What is NOFF.SHP {NOFF.SHR}?/FB



NOFF.SHR is an older version of NOFF.SHP.  So what's NOFF.SHP?



DESQview is the child of an older IBM program called TopView.  Because
Quarterdeck wanted DESQview to run all the old TopView programs, they
made DESQview compatible to TopView, in much the same way you can run
programs written for DOS 3.3 in DOS 4.0.



If a program writes directly to the video memory, TopView (and DESQview)
cannot run it in a small window.  So IBM allowed programs to be TopView-
aware (similar to DESQview-aware /JB(see Q3)/q3.txt/) by giving them ``virtual''
video memory on request.  This memory looks like video memory, but
characters written into it do not get displayed on the screen.



Since DESQview is a much smarter program that TopView ever was, DESQview
can automatically update the window from the virtual video memory.  But
TopView did not have that ability.  The TopView-aware program had to
make another call which would manually update the window from the video
memory.



Quarterdeck wanted to make DESQview look as much like TopView as
possible, so they decided that if a TopView-aware program makes this
call to update the window, then the automatic updating of DESQview would
be turned off.



DESQview can do a better job of updating the window from the virtual
video buffer than *some* programs.  So the purpose of NOFF.SHP is to
capture the TopView update call before it gets to DESQview and not let
DESQview see the call.  That way, DESQview never turns off the automatic
updating, and your window output is less jerky.



Whether or not you should use NOFF.SHP depends on how the TopView-aware
program updates its screen.  If it changes only small parts of the
screen at a time but requests that the entire screen be updated, use
NOFF.SHP.  But if the program tells TopView (DESQview) exactly which
part of the screen changed, output may look smoother without NOFF.SHP
because an automatic update doesn't take place until the end of each
program's time slice /JB(see Q9)/q9.txt/.



Although NOFF.SHP is included in the Quarterdeck-supplied DVP for
Wordperfect, it is not required if you are using a 386 or better and
you turn on text virtualization.