Vnc (Virtual network computing)

Vnc is a free program, very easy to install, and very small. You can run it off of a floppy, so, if you carry the floppy, you can use it from anywhere.

It is not a good idea to use it over a phone modem, although it works fine over dsl or any other high-speed connection.

Here is how to use it. I will give examples for both Cattell and Finzi. Finzi is my own (SAS allocation) computer, and it runs Linux. You can ask me for an account on it if you want one, and if you're nice I may give you one.

1. install vnc on whatever computer you are using, your "pc". Information about where to get it is in http://realvnc.com
2. log into finzi or cattell
3. say
   vncserver -ac
   if you are on finzi, or just
   vncserver
   if you are on cattell to start the server.

   It will ask you for a password. It is a good idea to make up a new password just for this.

   Look at what it says. In particular, look for something like New X desktop is cattell.psych.upenn.edu:1 Let's assume it is :1 at the end. That is important.

4. On your pc, say (at a dos command prompt)
   vncviewer cattell.psych.upenn.edu:1
   or
   vncviewer finzi.psych.upenn.edu:1
   and type your new password when asked. (If you are running from a floppy a:, you might say a:\vncviewer finzi.psych.upenn.edu:1.)
5. When you are done, you can end on your pc with F8. It is probably also a good idea to kill the server:
   vncserver -kill :1

What you get when you log in will be a window manager and an "xterm" window. In the xterm window you can type commands, as you usually do when you log in with telnet or ssh (SecureCRT, for example). But now you can use graphics commands too. Her are some useful (and not so useful) programs to try:

R and SPlus

languages for statistics and graphics

in R try the commands demo(graphics) and demo(image)

xfig

great program for making drawings, easy, with menus

nedit

A text editor (like Emacs and Pico) but behaves more like Word

netscape

the browser, mailer, etc. - use for getting past Penn's firewall

acroread

for reading pdf without downloading first

ghostview

for viewing PostScript

soffice

Sun's (free) answer to Microsoft Office

slow to load but very complete

handles PowerPoint, Excel, Word, rtf (but not Word Perfect)

xv

displays pictures quickly (gif, jpg, etc.)

xpaint

another drawing program

xdaliclock, oclock, clock

clocks

xeyes

supposed to help you keep track of the mouse pointer

maze

basically a screensaver (nothing compared to xscreensaver for Linux)

Hints:

1. The mouse pointer must be in the xterm window for you to type.
2. You can move windows by using the right mouse button on the top bar.
3. When you start a program, often you will get just a grid, with the mouse pointer in the upper left. Move the mouse to get the grid where you want it. Then click.

A window manager manages the windows in the X Window system. The default window manager is twm, which is roughly what you get when you use the X terminals in B3.

You can change your window manager in your .vnc/xstartup file, which is automatically created when you use vncserver. On Cattell, you might want to replace twm with olwm. Olwm is simpler, faster, less unintelligent, and less flexible than twm. It does not require you to decide where you want each window. It decides for you.

Many window managers are available on most Linux computers. For example, replace twm with gnome-session or startkde, to see the two most popular ones.

For more than you want to know about X and window managers, see the two things at the bottom of http://www.redhat.com/mirrors/LDP/HOWTO/HOWTO-INDEX/howtos.html

Jon Baron, 7/6/01