Virtual Network Computing Software

Scott Delinger (scott.delinger@ualberta.ca)

The Olivetti and Oracle Research Lab (www.orl.co.uk) has created a new software set that allows a user to view and control a remote computer. Netopia's Timbuktu Pro, reviewed in the September 1998 HyperDispatch, does this as well and has a large set of additional features, but Virtual Network Computing (VNC) is only for remote viewing and control (i.e., file transferring is not supported). VNC's main attractions are that it costs nothing, which is favorable to academics on tight budgets, and that it operates across more platforms than its competitors.

Of course, the main question is "Do you get what you pay for?" Initial reviews of the software say no -- in fact, you get much more than one would expect from a free software package. For the uses that the ORL team designed the software for, it works admirably.

The software was first designed as a viewer for X (a Unix windowing system) to run under Windows 95 and Windows NT 4.0. A viewer for Unix has since been added and a server for Windows, so you can view your NT box from your Unix workstation. There is also a Macintosh viewer in beta, and an alpha-quality Macintosh server. Note that the Unix and Windows source code is available for both the viewer and server.

Differences from Commercial Software

Stateless:

This means that you can leave the office computer in mid-sentence, drive home, connect to the office desktop with VNC, and complete the sentence after dinner.

 

Platform independent:

Virtual Network Computing software compares favorably in this important area. Timbuktu Pro, for instance, runs under Mac OS and Windows only, while eXodus, eXceed, and PC Xware are available for Windows to view X running on Unix, but the reverse is not supported. Macs can run eXodus, but you can't control your office Mac from Windows or Unix with any of the commercial packages.

 

Small and simple:

The VNC viewer client for Windows fits easily on a floppy diskette.

 

Multiple clients:

You can have several clients connected to one server, for use in a computer lab for demonstration purposes. Timbuktu Pro can do this as well, but the X software packages generally do not support this functionality.

 

Available source code:

Source code is freely available, so users can fine-tune the application to suit their own needs (or fix bugs).

Examples of VNC Usage

• If four people with Windows boxes all want to run X-based applications on one Unix computer, they can do this at no cost. (Similar capabilities are available for a price with Hummingbird's eXceed, White Pine's eXodus, or PC Xware.)
• A user at home at night with a Mac, Windows or Linux computer can run software on their office Windows or lab Unix computer.
• An administrator of an NT or Unix server can add a user account on the server from their desktop Windows computer. This makes it unnecessary to install the NT Server administration applications on their Windows 95/98/NT Workstation desktop computer, or to run down the corridor to the server console to make changes.
• A Macintosh user can run a Windows-only application on a nearby Windows computer.
• An NT or Unix system administrator can use GUI tools from home at night for minor administration duties or just to monitor system behavior.

Performance Considerations

Installation and configuration of VNC is simpler than that of Timbuktu Pro, mainly due to the fact that the program is much simpler, and there are fewer options.

I began by running the server on a Linux computer, with the viewer on an NT Server. Performance was very good with a few simple graphically static X applications and X-based Netscape Navigator. To increase the challenge, I started xsnow. My VNC viewer on the NT Server ground to an intolerably slow rate of refresh. I killed the xsnow application, and VNC sprang back to life. Using VNC to run Netscape on the computer being viewed resulted in acceptable performance. Viewing streaming video with VNC is unlikely to be acceptable, but most business uses will be quite satisfactory.

I then installed the VNC server on my NT Server, and tried to run the vncviewer binary for Linux. I had to reinstall the vncviewer application on the Linux box to get it to run, but after that reinstallation I was successful. While performance was acceptable, my impression was that running the viewer on NT and the server on Linux was faster than the reverse. This subjective observation was supported by the documentation available from ORL.

Since I also have a Power Macintosh available, I installed the beta viewer there and connected to both the Linux and NT servers. I did not have any difficulties with the viewer that I would normally expect with a beta release of freeware. Everything worked as expected and the graphics refresh rate was sufficient to make the Mac viewer/Linux server a no-cost replacement for eXodus on my desktop. I did not test the alpha Mac server, which would allow running my Mac from another Mac, a PC, or Unix box.

To test the software on a slower connection, I installed the viewer on my Macintosh Performa 5260 PPC at home, which is connected to the Internet via cable modem. Although the documentation says that the viewer will run under either MacTCP or Open Transport, I was unable to get the client to run under MacTCP.

Conclusions

Virtual Network Computing is a useful set of free network applications, which offer remote control or viewing of Mac, Windows (95, 98, NT), and X applications running on remote computers. Running X-based applications remotely is one of VNC's strong points, but equally valuable is the ability to run your office PC from your home computer over a dialup connection to any ISP. Because the software is free, the price/performance ratio is near infinity! It is definitely worth a look for people who cannot finish their computer-based work within the eight-hour day.