winvncdrv new version available

James ''Wez'' Weatherall jnw22 "at"
Mon, 04 Mar 2002 15:27:00 +0000

The existing official version of WinVNC can only obtain hints as to changes
to the display, which it must then verify since they sometimes overestimate
what has changed.  Conversely, some updates (some scrolling, some console
windows) cannot be hooked for hints, so WinVNC polls them, chewing the CPU.

Using a display driver allows WinVNC to obtain accurate data on what has
changed, vastly improving performance (try moving the mouse pointer with the
two different versions and the difference can be very noticable - and that's
a relatively small graphical update!).

Essentially, the display driver is the way WinVNC should have operated from
the beginning, but since it works only on NT and could cause system
instability, we opted for the hint route instead, which is more portable (to
Win98, for example) and cannot crash the OS.  (Note that Rudi's version uses
a hook driver that I've never seen crash a system, so the instability point
is probably moot).


James "Wez" Weatherall
          "The path to enlightenment is /usr/bin/enlightenment"
Laboratory for Communications Engineering, Cambridge - Tel : 766513
AT&T Labs Cambridge, UK                              - Tel : 343000

Date: Sun, 3 Mar 2002 10:50:41 -0500
From: "John Roland Elliott" <John_Roland_Elliott "at">
Subject: Re: winvncdrv new version available

Considering the originator (R. De V.), I'm certain that this is a truly
innovative solution to a problem that I suffer, but I can't figure out which
one? Is there someone out there who can offer a succinct statement of what a
VNC video driver does for me and what limitations it imposes? Thanks.
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