🚀 go-pugleaf

Okay, here is a stumper for those who are experts with video
cards and with WordPerfect.  

Part of why people buy Pentium computers with 90 MHz processors
with lots of cache memory is so that everything will happen fast. 
The idea is that you would not have to wait very long for the
computer to do things.  My previous computer, a 386, was a bit
sluggish sometimes especially when I was doing something halfway
complicated in WordPerfect, like a print preview or scrolling
through a document.  Of course, it has always been well known
that WordPerfect 6.0b for DOS, with its rather inefficient code,
is a slow program.

So here is the super-duper Dell XPS P90 computer, with a Pentium
processor and a Number 9 Computer Corp. GXE64 Pro VESA video
display board.  Lots of things happen fast with this computer.  I
figured this processor would make up for anything that is
inefficient about WordPerfect.  And indeed it does make up for
some of the things that are inefficient about WordPerfect.  Print
previews are less slow.  Setting up to send a fax does not take
so long.  Opening a large file does not take as long.

So the next thing I figured was, why don't I take advantage of
the high resolution available with the video board?  The video
card and the monitor are both good for 1024 by 768 lines, so why
not use them, I figured.

It took a bit of work to figure out how to do this.  But
eventually I managed to determine that the display setup screen
is the way to do this.  With advice from the Number 9 people, I
selected a WordPerfect video driver called "VESA 1024x768 256
color".

The question is, why is my super-duper computer, when it runs
WordPerfect for DOS in 1024 by 768 mode, painfully slow to scroll
down the screen?  If I hit the downarrow repeatedly to reach the
bottom of the screen, and then hit downarrow again, the screen is
painfully slow to repaint the screen.  The whole screen gets
repainted from top to bottom, so slowly that I can actually watch
the cursor move line by line down the page until the screen has
been repainted.  If I hold down the downarrow key long enough to
make it repeat, there is a very painful repeated redrawing that
takes place repeatedly.  Scrolling down the length of a page can
take twenty seconds or more!

I would have hoped that the way a screen scroll takes place is
that the video memory contents are block-moved up or down in a
very efficient way, mostly in hardware and very little in
software.  But the impression one gets, watching the screen, is
that with this driver the contents of the video memory are
rewritten under processor control from the first pixel to the
last, whenever the cursor hits the top or bottom.

If I change back to a VGA driver the scrolling is just as fast as
always.  But if I select the VESA driver at 1024 x 768 (16 colors
or 256, makes no difference) the scrolling is painfully slow.

So can someone tell me who is to blame?  Is WordPerfect to blame
for writing a particularly inefficient VESA driver for its 6.0b
for DOS?  Is Number 9 to blame for designing particularly slow
video hardware?  Or is it something completely different?
-- 
Carl Oppedahl AA2KW  
Oppedahl & Larson (patent lawyers)
Yorktown Heights, NY  
oppedahl@patents.com