NIU Math Help

NIU Department of Mathematical Sciences
X-Windows

Our workstations use a graphical display system called X11, designed at MIT. If you don't have a strong preference for the alternative, Sun's OpenWindows, we urge you to use X11 which requires less memory.

All software which uses graphics (Netscape, PostScript and DVI previewers, image viewers) must run under such a graphical user interface; moreover many ordinary non-graphics programs run better under X-Windows. That's why it is important to learn using it.

Starting X11

You can only start X-Windows on the computer you are in front of, i.e. when you are physically sitting at the workstation. Do not try any of what follows if you are logged on remotely by modem or over the network.

Just after you log in type the command xinit and press Return. The screen should become gray, and some windows will start popping up. On the slower machines the whole process can take half a minute or so.

From now on you'll be doing many things with a mouse. Most of the time the left mouse button is used. The interface is somewhat similar to Microsoft Windows or the Macintosh Finder, but there are several differences and it will be confusing at first.

Carrying on

You should now see a clock and a few windows and icons. Let's start with the icons. Move the mouse pointer on top of a small icon labeled "home3" and click the left mouse button. The icon should change into a window with a Unix prompt in it. Type some command in it, like ls. You should see the listing of your files. Each window is a separate environment, as if you were logged in several times simultaneously.

Now click the box with a circle inside, in the top left corner of the window. The window goes away, but not entirely - it just shrinks and becomes an icon again.

Open a window again; press and hold the left mouse button in the middle of the title bar, the shaded bar at the top of the window. When you "grab" the title bar like this, the window will move about along with the mouse until you release the button. That's how you can rearrange most of the windows on the screen.

To resize a window, do the same - click and hold the button - but this time inside the box in the top right corner. When you move the mouse and it hits any edge of the window, that edge will start moving. This lets you make a window smaller or larger. But it's not a good idea to do that while the window shows some application (like elm or an editor) which displays things depending on the original size of the window - such programs will get confused and you may see bizarre results.

If one window is partially covered by others, you can bring it to the front of the display by clicking it once on the title bar. This is fine when the title bar is visible - but what if the window you want to get at is completely covered up? You can tell the window in front to jump all the way to the back by clicking the title bar with the middle mouse button. It is somewhat difficult to describe this with words, so you should now spend some time playing with the windows.

Running programs

You can start various programs by typing a command in a window. In some cases, when the program does not use graphics, it will simply run inside that window as if it were the computer's screen. Try the pico editor or elm to see how that works.

Other programs, such as netscape or nedit will open their own window - when a "wireframe" outline shows up, move it with the mouse where you want it to be, and click the left button to place it on the screen.

The computer can run several processes at once. To take advantage of that try saying nedit &. The ampersand will make the program "run in the background", so you can continue doing other things in that window. But be careful about starting up too many programs - some, especially Netscape, eat up quite a bit of memory. This may slow the computer down to a crawl, or make it stop responding altogether. In that case use another workstation to send mail to the system manager who will try to clear things up.

Getting out

First quit all applications you started - mail, Web browser, etc. Then type exit in all or at least most of the windows. Finally, move the mouse anywhere over the gray background, press and hold the left button. A menu will pop up. Holding the button down slide the mouse all the way to the item "Exit" and let go of the button. After a while the screen will clear and you'll be back where you started. Type exit one more time to log out all the way.

Customizing your setup

Positions of windows, font sizes, menu items etc. can be changed by modifying a few configuration files - .xinitrc, .twmrc and .Xdefaults. However, doing this the right way is not trivial. Please do not attempt to do so until you learn much more about the way X11 works. For now just mail your requests to admin@math.niu.edu and the system manager will try to adjust the settings to your liking.