Networking:VNC on the Nokia 770

From Internet Tablet Talk

VNC copies a bitmap of a remote computer's display acrosss the network. It's a static display image, not one that is rendered by any data or algorithms. A VNC display is not the display portion of an application that is running remote to you as an X server display is. It is merely a static copy of the display on that remote computer at a given moment of time. You can interact with the image and you can make use of the remote computer but you wouldn't want to do this while anyone else anywhere were also using that computer.

Here are the steps to installing a VNC viewer on the 770.

- install xterm - copy vncviewer.bin onto the MMC - start xterm - type:

  cd ~ cp /media/mmc1/vncviewer.bin . ./vncviewer.bin 

  hostname:portnumber -passwd=yourpassword

The default port for VNC is 5900 but, like SSH, VNC installs can be run on other ports.

VNC does not render the graphical display remotely as X does but merely displays a bitmapped image from the remote display, copying it and sending it over the network. It therefore is an approach to remote display which is marked by noticeable delays, the time it takes to move the images over the network.

To alleviate some of the latency (i.e., delay) that accompanies the movement of a full screen bitmap acrosss the network for each screen refresh from the remote computer to your N770 the bitmap can be compressed. A FreeNX-client can provide the NX protocol (a compressed and secure forwarded X-session). FreeNX is a free alternative to NoMachine NX which is based on the NX core libraries.

X is a transparent network protocol so X sessions have advantages over VNC sessions but of course X sessions are restricted to situations where X is installed on the remote computer or device. Advantages include the ability of the display to handle rendered GUIs in native mode; refreshing rendered X GUIs incurs substantially less latency than does refreshing of compressed, bitmapped VNC GUIs.