Serial Networking: Using VNC Over The Network

If you do not have a fast serial port on both RISC OS and PC computers(115200 bps plus), then do not read any further. This is because VNC requires a lot of network bandwidth to function.

What is VNC?

VNC is a network protocol which allows full use of computer with a VNC server running, without the user sitting in front of that computer. The user simply sits at a machine with a VNC client running (in this case a RISC OS computer), and controls the remote computer through a window that contains a representation of the remote computers desktop or command line.

At the current state of play it is only practical to have the RISC OS machine as a VNC client, and a Windows or Linux box as a VNC server. This is due to the fact that the VNC server for RISC OS computers is slow and only functions if the computer is in a 256 colour mode.

Using a 115200 bps serial port with VNC, it is possible to word process at an acceptable speed on a PC from a RISC OS machine. In fact this webpage is being authored in such a manner as an experiment. However, any application that will require fast screen updates on the PC will not be suitable.I have also managed to operate Samba Server at the same time as a VNC client on my Risc PC, allowing me to transfer files to and from my Risc PC and PC hard drives. (NB. The file transfer rate was severly cut by VNC usage, however.)

What will you need?

A VNC server for your Windows computer: http://www.realvnc.com/

A VNC client for your RISC OS computer:

VNC by Simon Truss: http://www.bigblue.demon.co.uk/VNC.html
VNCViewer by Leo White: http://www.brighteyes.u-net.com/html/download.html

The functionality of the two RISC OS VNC clients are about the same, so I would suggest you try both of them, to see which one you prefer.

How do you set it up?

If you have the serial link already set up, then this should be a simple process.

1) Initialise the serial link.

2) On the PC run the VNC Server: Click on the Run VNCApp icon in the VNC directory, which is contained in the Programs Menu. The first time you run it, you will have to enter a password, which you will need to remember for connecting the RISC OS VNC clients.

3) Run the RISC OS VNC client:

(NB. I have deliberately set the Colour settings to 8bpp (256) colours, to reduce the VNC network bandwidth requirements)

	a) VNC: Run the application. Click the middle button over the icon bar VNC menu, and select the Connect... menu option. Fill out the resulting window as follows: Colours: 8bpp Fixed Hostname: novapc Password: <Enter the password you inputted for the Windows VNC server> Display: 0 Now click on the Start Session button. After an initial delay, the PC display should appear.
	b) VNCViewer: Run the application. Click the middle button over the icon bar VNCViewer menu, and select the Options... menu option. Fill out the resulting window as follows: Encoding Type: Tick all the options. BPP: 8 True Shared: Tick Always track mouse: No tick Disable Nagle Algorithm: Tick Poll time: 10 cs Mouse Update: 4 Click on the Save button.
	Now click the middle button over the VNCViewer icon, and select the Connect... option. Fill out the resulting window as follows: Server: novapc:0 Now click on the Connect button. VNCViewer will prompt you to input the VNC server password. If the password is correct, after an initial delay the PC display should appear.

4) You should now have a functional, if slow, VNC connection to your PC.