Article by Kevin Savetz

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Copyright © by Kevin Savetz

This issue, we take a look at Virtual Network Computing, an amazing tool that will let you access your computer from any other computer on the Internet.

-.-.- Virtual Network Computing -.-.-

I walked into my office and was flabbergasted. My buddy Mitch, visiting from out of town, had been working at my Mac for a few minutes. When I saw the screen, I did a double-take. On my Macintosh's screen was a window that showed not the familiar Mac icons, but a Windows NT desktop. It was, in fact, the desktop of Mitch's computer some 350 miles away. Mitch was able to control his computer, running programs, switching between them, mousing around and typing DOS commands from my Mac. A minute later, he logged onto another computer running Linux.

The magic, I soon learned, was a tool called Virtual Network Computing, or VNC. VNC is a free program that allows you to control a computer that is connected to the Internet from any other Net-connected computer. Your local keyboard and mouse control the remote computer, and what its screen shows, your screen shows.

There are two parts to VNC: the server, which must be running on the computer that you want to access remotely; and the client, the software that provides your window to the remote computer. The server and client computers can be across the room or across an ocean, as long as both have a Net connection.

The server and client computers don't need to be running the same operating system -- you can access a Windows NT machine from a Macintosh laptop, for instance. Server and client software are available for Windows 95 and NT, Linux Solaris, and DEC Alphas. Clients are also available Macintosh, Java, Windows CE and PalmPilot(!). So while you can't access your desktop Mac while on the road, you can mix and match in many other combinations.

VNC makes it easy to pick up work on your computer from just about any other computer with a Net connection. You can be typing a sentence at your office computer, hop on a plane to Rio, log in with your laptop and type the rest of the sentence on the office machine. Assuming, that is, that you've installed the VNC server on your office computer and it is connected to the Internet. (To be accessible when you need it, you need either a permanent Internet connection for your server or a helpful co-worker who can walk over and dial in its modem.)

Using VNC isn't quite as good as being there. The chief difference is speed. Every time something on the remote computer's screen changes, such as cursor movement or a new window appearing, that information must be sent to the client computer. When lots of screen changes are sent, especially over a slow connection, it results in a sluggish interface. VNC works well with programs that display windows that don't change quickly -- like word processors, command line windows, even web browsers work well. VNC can't keep up with fast-changing screens like games and screensavers.

The trick to getting the speediest screen updates is to set things up so VNC has to send as little information as possible. This means foregoing that beautiful desktop picture for a plain color background and setting your display to 256 colors rather than millions. With a pretty picture in the background, it takes several minutes to transfer the desktop initially, and it is almost unusably slow over a 28.8 modem.

The speed of the Internet connection of both computers is the biggest factor that affect's VNC's usability.

My friend Mitch has been using VNC for months to telecommute. He uses a computer running the Linux operating system at home to communicate with his Windows NT machine at work. Over a 28.8 KBPS modem and with a solid desktop, Mitch calls the system slow, but usable. "It would be painful to work on all the time, but it is great for those times when there is some utility on my computer at work that I just don't have at home. It's certainly better than a one- or two-hour commute."

Over a high bandwidth link like ISDN, accessing a computer with VNC is sluggish but bearable. If both computers are on the same local LAN, access is swift. My home office are two computers, a PC and a Mac, that share one monitor. Rather than switching cables or messing with a fussy monitor switch, I now run the VNC server on the PC so I can access it from the Mac.

If you print something with VNC, it will indeed print -- on the remote machine's printer, not your local printer. Also, if you copy something to the clipboard in the VNC window, it doesn't affect the local machine's clipboard. So VNC doesn't make it easy to move information from one computer to another. The best solution I've found is to use VNC to access the e-mail program on the remote computer then mail files to myself at the local one.

Occasional video glitches do occur, and rarely certain events like mouse clicks aren't registered the first time. Nonetheless, VNC is an extremely convenient tool that can give you access to an otherwise inaccessible computer.


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Articles by Kevin Savetz