[K12OSN] Cygwin X for windows - run from CD

Les Mikesell les at futuresource.com
Thu Dec 16 13:52:26 UTC 2004

0On Thu, 2004-12-16 at 02:31, Robert Arkiletian wrote:

> What's the technical difference between forwarding X with cygwin and 
> just using TightVNC? Pros/Cons of each.

X is a complicated, layered protocol with a lot of primative drawing
and graphic operations that can be used to display an entire desktop
or a single application window to a different machine over the network.
VNC uses simple bitmap compare/copy operations to duplicate the way
a display looks without knowing much about the operations that created
it.  On a fast network, using X directly will be faster.  However X
has to wait and complete each operation while VNC can allow the remote
display to get behind during fast activity and can skip some
intermediate changes if bandwidth is low without making the application
wait.  Then it will update the display to match when it stops changing
so it may be faster to use over a slow connection.  VNC was designed to
be simple and portable but extra features like scaling and different
compression techniques have been added to some versions.  There are
windows/X/Mac/palm and many other versions, both client and server.

> Also, how does FreeNX compare 
> with these two solutions?

FreeNX works as a compressing proxy for X.  That is, it can only work
with X on the server side where it tries to optimize what it sends to
the remote.  It knows more about the X protocol than VNC, so font
display and some other operations are handled directly by the client and
can be more efficient.  There will be some tradeoff between RAM and CPU
use on the server to run the freeNX proxy vs. the bandwidth saved by
the optimizations but I haven't seen real tests to show how this plays
out with a large number of users on a 100M LAN.

  Les Mikesell
   les at futuresource.com

More information about the K12OSN mailing list