VNC logo

Virtual Network Computing

[getting started]
[keep in touch]
Others' ports and add-ons etc
Project ideas
VNC people
[AT&T Laboratories Cambridge]
Some recent changes: 
Windows packages updated to 3.3.3r9 - 19/3/01
No virus in WinVNC! - 8/3/01
A list of all known encoding numbers in use - 8/11/00
Unix packages updated to 3.3.3r2 - 26/10/00
Note: The FAQ and some other bits of the documentation are
constantly being updated. We only record major changes here.

What is VNC? - A practical introduction

VNC stands for Virtual Network Computing. It is, in essence, a remote display system which allows you to view a computing 'desktop' environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures. 

Example screenshots using X desktops

The VNC system allows you to access the same desktop from a wide variety of platforms.
Many of us, for example, use a VNC viewer running on a PC on our desks to display our Unix environments which are running on a large server in the machine room downstairs. 

What makes it different from other systems?

For this simple mode of operation, you could achieve a similar effect by installing an X server on your PC. The important factors which distinguish VNC from other remote display systems such as X are as follows: 
  • No state is stored at the viewer. This means you can leave your desk, go to another machine, whether next door or several hundred miles away, reconnect to your desktop from there and finish the sentence you were typing. Even the cursor will be in the same place.   With a PC X server, if your PC crashes or is restarted, all the remote applications will die.  With VNC they go on running.
  • It is small and simple. The Win32 viewer, for example, is about 150K in size and can be run directly from a floppy. There is no installation needed.
  • It is truly platform-independent. A desktop running on a Linux machine may be displayed on a PC. Or a Solaris machine. Or any number of other architectures. The simplicity of the protocol makes it easy to port to new platforms. We have a Java viewer, which will run in any Java-capable browser. We have a Windows NT server, allowing you to view the desktop of a remote NT machine on any of these platforms using exactly the same viewer.  (The NT server is not multi-user - see the documentation). And other people have ported VNC to a wide variety of other platforms. Click the 'Contributed' button on the left for details.
  • It is sharable. One desktop can be displayed and used by several viewers at once, allowing CSCW-style applications.
  • It is free! You can download it, use it, and redistribute it under the terms of the GNU Public License. Both binaries and source code are available from the download page, along with a complete copy of this documentation.

Where does the name come from?

The name originates from our development of very-thin-client ATM network computers. The Videotile was essentially an LCD display with a pen input and a fast ATM connection. Because the VNC viewer is a software-only version of this 'ATM Network Computer', and so provides 'workstations' which can be created or deleted at will, we named the system Virtual Network Computing. 

Can I see what VNC looks like?

We have some screenshots of very simple VNC desktops running and being displayed on a variety of platforms. 
Follow the links on the left to find out more...
For comments, feedback, etc, please see the 'Keeping in touch' page.
Copyright 1999 - AT&T Laboratories Cambridge