On Friday, 4 December 1998,
     MARIO SEMO wrote to IVAN TODOROSKI about PM drawing priorities...

 IT>>   Well... I don't think it is stupid, since it also stops all the
 IT>> other   more important things on my machine! Infact, it totally
 IT>> freezes all   non-TimeCritical threads!

 MS> my point was just: WHO needs painting while dragging? turn it off
 MS> and the effect is gone? (or do you see the problem too when you
 MS> turn this feature off)?

   But this wasn't my point. The dragging problem was just an intense
   manifestation of the problem with the priorities of the threads that
   did the actual redrawing of windows. If I turn full-window dragging
   off, the applications won't freeze when I drag windows around, but
   that DOESN'T eliminate the real problem.

  What if an application decided to go crazy in a loop redrawing itself
  (like some FLC/AVI/etc viewer for instance)? Does this mean that
  everything else should stop while it's doing this? What if I have a
  BBS in the background, what if I run some server? Remember, the
  application is running at Regular-0 priority, and it STILL freezes all
  the other Regular-0 threads!

   This is a potential problem, a bottleneck. Other windowing systems
   (most notably X) don't have this problem. If there are background
   processes competing for time, drawing of windows DOESN'T take away
   all the cycles from them. The redrawing gets slowed down, so the
   background processes don't stop completely, even on my slow machine
   (which is what multitasking is all about).

  When a PM window gets redrawn intensively (no matter if it is caused
  by dragging it around, or the programmer made it to redraw intensively
  in a loop), background applications stop on slower machines.

  Full window dragging was just put out as an example, as an easy way
  of inducing and observing this effect.

                                                            - Ivan -

.!. Apathists of the world ... .. ahh, forget it!
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