From: gt8741b AT prism DOT gatech DOT edu
Subject: Re: Want vbl interrupts
To: djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp mailing list)
Date: Fri, 4 Jun 1993 09:34:18 -0400 (EDT)

> 	I need to arrange to have an arbitrary C function of mine called 60  
> 	times a second.  setitimer() doesn't seem to be supported.  I've  
> 	noticed that the PC has the appropriate VBL interrupt, but I do not  
> 
> Try reading the rec.games.programmer news group.  There you would probably
> hear that PCs (of the IBM compatable sort), do NOT have a vertical blank
> because you are looking for something to automatically execute a routine

I think that if you are not doing sound, you can somehow tie the output of
that timer to an interrupt.  I am not sure, I am just suggesting something
that you might look for.  If you are trying to tie something to the VBL, be
aware that it probably isn't 60 Hz.  The monitors and graphics cards can do
pretty much whatever rate they want.

> on interrupt.  Coming from the Atari ST platform, I find this to be quite
> a step in the non-forward direction.

Coming from the Atari 8-bit platform, I find this to be a large backword step.
Atari had 4 voice sound and 256 colors (ok, low resolution, but what do you
expect on a TV set?) in 1979.  When I stepped "up" to a PC clone, I was quite
suprised at the lack of things such as the vertical blank interrupt and decent
sound support.
-- 
Chris Adams                       | "Don't touch that!  That's the history
Georgia Tech                      |  eraser button!" - R&S
Internet: gt8741b AT prism DOT gatech DOT edu| "I chortle at thee, thou pathetic
----------------------------------+  chucklehead!" - the Wizard