nelson_p@apollo.HP.COM (Peter Nelson) (02/26/90)
Your roving troubleshooter (or is that troublemaker?) recently
installed Desqview 386 (i.e., Desqview 2.2, QEMM 386, and Manifest
on his 386SX machine (2M, ATI VGAWonder).
So far, everything runs properly under Desqview except for
several graphics applications written in Zortech C using their
Flash Graphics library. The Zortech programs run fine outside
of Desqview. But they behave unreliably under Desqview, some-
times crashing during initialization, sometimes crashing later
on, sometimes not crashing at all. This occurs even when there
are no other apps running under Desqview and no TSR's except
Logitech's mouse.com. Running with protection set to [3] may
no difference and results in no error messages. By "crash" I
mean that the whole machine hangs and has to be rebooted.
The programs in question are small (~35K) and allocate no
global memory. All they do is init graphics (640X480 X 16
colors), draw two colored rectangles on the screen and allow
the user to change the colors of one of them via the LUTs
(palette) using the R,G,B keys of the keyboard.
I've tried various suggestions in the manual to no avail. Of course
there's a lot of material there, between the 2.2 manual, the 386
addendum, and the QEMM material. I haven't got time to become an
"expert" in their product; I just want to be able to run my
programs.
Desqview's troubleshooting guide was no help. They have a section
for developers which talks about writing "Desqview oblivious"
programs. There they provide a list of "don'ts" which basically
amount to "don't write your program as though it owns the machine"
and which consists of specifics about buffer and stack sizes and
interrupt handling and not 'going around' DOS, etc.
I don't like this for three reasons:
Both advertising literature I have from them and conversations
I had with them before buying indicate that Desqview can create
an environment in which a program can "think" it owns the machine.
I had extensive conversations with their tech support staff before
buying the product in which I tried to poke holes in this but was
assured that there was very little likelihood of a problem.
I chose Desqview over Windows 386 because I didn't want to
have to rewrite my applications in order to use them under
Desqview.
If you are writing in a high-level language like C or Pascal
you are not likely to *know* whether the conditions for their
"Desqview oblivious" programs are met. How do I know what
Zortech's run-time code and graphics library do internally?!
And more to the point, Zortech is written for DOS, which is
a single-use operating system, so why shouldn't Zortech think
it owns the machine? This is not a realistic requirement for
Quarterdeck, Desqview's manufacturer, to make.
I'll call Quarterdeck's tech support on Monday and see what they
have to suggest.
BTW, if all else fails, I am happy to report that Quarterdeck
DOES have a 90 day money-back guarantee on their product. I
just hope I don't have to use it.
---Peter