Using XDarwin on the Triangle Lab iMac

Accessing a Unix Lab Account from the iMac Using XDarwin

XDarwin is the Mac OS-X version of X windows, a rudimentary but fully functional graphical interface for Unix-based operating environments. Using the XDarwin interface, you can run graphical Unix programs, such as Netscape, ArcView and Imagine.

To start XDarwin, click on the XDarwin icon on the "dock" at the bottom of the screen: 

If XDarwin is not already running, a window should open that looks like this:

Select full screen by clicking on the "Full screen" button. ("Rootless" will keep the Mac desktop visible in the background, making it a little more confusing if you're not accustomed to it.)

You should then see another window that looks like this:
 

 
Remember these instructions. The "Command" keys are on each side of the spacebar on your keyboard, the ones with the picture of the trademark Apple. The "Option" keys are just next to those. Using the combination "Command-Option-A" will allow you to instantly switch back and forth between the iMac desktop and the XDarwin (X11) interface. (From the iMac desktop you can also click on the XDarwin icon on the "dock" to return to XDarwin.)

Click on the "Show X11" button to start the interface. The iMac desktop should disappear and be replaced by grey-patterned background, and the mouse arrow will change to an X-shape.
 

When you first enter the XDarwin graphical interface, you should have some terminal windows already open, all with the internal prompt of the iMac's Unix system. From any of these you can execute familiar Unix commands, such as ls to list files and cd to change directory.

Some basic points:

When first opening a program, XDarwin will not automatically place the program window on the desktop, but instead brings up a grid outline of the window that follows the mouse cursor movements. This allows you to select the location of the window on the desktop before it actually opens. When you have the window's outline where you want it, click the mouse button and the window will open.

To move a window, click-and-drag the titlebar. The window's grid outline will appear, allowing you to relocate the window. Once the outline is where you want it, release the mouse button.

To resize an open window, click-and-drag the box in the upper right-hand corner of the window. This will bring up the window's grid outline. Once the outline is the size you want it, release the mouse button. If you have a hard time getting the window to resize, try going larger before going smaller. For some reason, the window size doesn't "release" unless you do.

To bring an open window into the foreground, you need to actually click on the title bar of the desired window. Clicking anywhere else on a window will not do it. You may have to move a window already in front in order to access the title bar of a window in the background.

To open another terminal window, place the mouse cursor on the grey desktop and click. This brings up a pop-up menu. Click on the item "xterm" to bring up another terminal window.

To close an xterm terminal window, type exit at the prompt. (Note: This is true only for windows labeled "xterm". If you type exit in the window labeled "login" it will exit the XDarwin graphical interface.)

Mouse button emulation: You may have noticed, but the iMac mouse has only one button. Since most Unix-based programs are designed for three buttons, XDarwin uses a work-around called button emulation. To use the middle-button functionality, press the Command key (on either side of the space bar with Apple logo on it) and click the mouse button. To use the third-button functionality, press the Option key and click the mouse button.

Connecting and Logging In to the Remote Server

To access your Unix lab account and home directory, you need to connect to a remote server (in this case, elwood.nr.usu.edu) using ssh, the Secure Shell program.

To connect to your Unix lab account, type the following at the prompt:

ssh -l username elwood.nr.usu.edu

(Note: The character -l is a dash followed by a lowercase L.)

For example, if my username was gia14, I would type: ssh -l gia14 elwood.nr.usu.edu

After that, you should be asked to enter your password. (Note: You won't see your password on the screen as you type it.) Once you enter your password, you'll be at the familiar Unix prompt for your account:

username@elwood:/home/username>

Your directories and files can now be viewed and accessed. Also, unlike the iMac Terminal, you can run graphical programs (Netscape, Emacs, Imagine, etc.) on the Unix system. When you start a graphical program on the Unix system, the graphics will be displayed on the Imac through XDarwin.
 

Once you are finished accessing your Unix account, you need to logout of the remote server. To do this, simply type logout at the prompt and you'll be returned to the iMac's internal prompt.

Exiting the XDarwin Graphical Environment

You can exit XDarwin one of two ways:

- Type exit at the prompt in the window labeled "login" (Typing exit in the  other open terminal windows labeled "xterm" will only close those individual windows.)

- Use the key combination "Command-Option-A" to return to the iMac desktop and close the program from there.