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blank screen when doing graphics in tp for dos 7

Hi there.

My students are using Turbo Pascal for DOS 7. One of them has trouble
running programs that deal with graphics. Whenever she runs such a
program she just gets a blank screen. If she changes the background
colour, she's able to see that--but she can't see anything else. When
I run the program on my computer it works fine, though. She's using
Windows XP, which I don't have, but she says a friend of hers who also
has Windows XP is able to run the programs. Any ideas?

Dave
-------------------
Dave Switzer
CS 112 DE Instructor
School of Computer Science, University of Waterloo

 

Re:blank screen when doing graphics in tp for dos 7


Quote
"default user" <defa...@math.uwaterloo.ca> wrote in message...

> My students are using Turbo Pascal for DOS 7. One of them has
trouble
> running programs that deal with graphics. Whenever she runs such a
> program she just gets a blank screen. If she changes the background
> colour, she's able to see that--but she can't see anything else.
When
> I run the program on my computer it works fine, though. She's using
> Windows XP, which I don't have, but she says a friend of hers who
also
> has Windows XP is able to run the programs. Any ideas?

My first instinct was Windoze XP is at fault ('cause I've been hearing
things about less DOS compatability in Windoze XP). But since you
mentioned that her friend uses the same OS & the program works for her
then it could be something else.

My second instinct is maybe she has a lot more memory than her friend.
I've seen some people (with other programming languages) have problems
with DOS programs when their computer exceeds certain memory compactly
(>64Mb), I thought this is due to the DOS program can't work that far
ahead.

Might be worth trying to go into the programs file properties (if you
can in Windoze XP) & clicking on memory & disable the auto's in the
different memory columns. Set conventional memory to 640Kb & any
extended memory just set to a small amount.

Hope this helps.

Regards,
Ross.

Re:blank screen when doing graphics in tp for dos 7


"Ross Simpson" <rosssimpson@my_spammers_address(optusnet).com.au> schreef
in bericht news:3d083b7b$0$21001$afc38c87@news.optusnet.com.au...

Quote
> "default user" <defa...@math.uwaterloo.ca> wrote in message...

> > My students are using Turbo Pascal for DOS 7. One of them has
> trouble
> > running programs that deal with graphics. Whenever she runs such a
> > program she just gets a blank screen. If she changes the background
> > colour, she's able to see that--but she can't see anything else.
> When
> > I run the program on my computer it works fine, though. She's using
> > Windows XP, which I don't have, but she says a friend of hers who
> also
> > has Windows XP is able to run the programs. Any ideas?

> My first instinct was Windoze XP is at fault ('cause I've been hearing
> things about less DOS compatability in Windoze XP). But since you
> mentioned that her friend uses the same OS & the program works for her
> then it could be something else.

> My second instinct is maybe she has a lot more memory than her friend.
> I've seen some people (with other programming languages) have problems
> with DOS programs when their computer exceeds certain memory compactly
> (>64Mb), I thought this is due to the DOS program can't work that far
> ahead.

> Might be worth trying to go into the programs file properties (if you
> can in Windoze XP) & clicking on memory & disable the auto's in the
> different memory columns. Set conventional memory to 640Kb & any
> extended memory just set to a small amount.

My guess is that there is something wrong with the palette settings or
with the RGB settings. Normally at computer start up these have some
initial settings, but it may be Windooze that mingles up the settings,
giving them all a nice value of zero. The BGI drivers do not initialise
these settings upon invoking graphic mode. If neither the hardware does,
you'll have a blank screen.
This explains the changing screen color when you change the background
color.

 Look in the TP help function (shift F1) for Setpalette and all the
related items.

Using a better BGI driver might solve your problem.
E.g. SVGABG55.ZIP is one that usually works fine in TP real mode.

A very good one, but not for free is the Ryle driver set
www.ryledesign.com
They are still supporting their drivers up to today, so all problems like
this is thougt of.

Femme

Re:blank screen when doing graphics in tp for dos 7


Quote
default user wrote:
> I run the program on my computer it works fine, though. She's using
> Windows XP, which I don't have, but she says a friend of hers who also
> has Windows XP is able to run the programs. Any ideas?

Maybe it's a bug in the device driver for the graphics card. Do they
different cards/driver versions?

Robert Riebisch
--
 "Kennen Sie das auch? Alle anderen Postings sehen sch?ner aus?
Und sind viel besser zu lesen? Das mu? nicht sein! Ein Blick auf
             *** http://quoting.is-easy.de/ ***
  und fr nullkommanuffzich haben auch Sie sch?ne Postings."

Re:blank screen when doing graphics in tp for dos 7


Quote

> Maybe it's a bug in the device driver for the graphics card. Do they
> different cards/driver versions?

I think that to, since under W2K all my graphics DOS Apps didn't work.
Now with an updated driver they work!

Greetings

Markus

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