Basic Usage of the Computer System

This document assumes you have some familiarity with graphical user interfaces and windowing systems, like MacOS or Windows.

 

Our system consists of one main server called theory (a Dell PowerEdge 2650), and a number of NCD terminals running as dumb terminals. We also have a number of Linux boxes.

Using a dumb terminal

You are using a dumb terminal if the computer on your desk is a thin gray box with the letter NCD. This box will allow you to run programs on theory, as if that were the computer sitting on your desktop. All your files and mail from theory should be accessible from the terminal

When you first login, you should see a blue Workspace with a clock at the upper right, a terminal window with "theory" printed on the title bar, and a Mail Tool icon at the bottom. You can start many other programs through the menu which pops up if you press the third (right) button while the pointer is anywhere on the blue background.

The terminal window operates as if you were working directly at the server; you can enter commands in response to the prompt. However, you cannot write in the window unless the mouse is located somewhere inside it. You can move the terminal window (or any window) by placing the mouse on the title bar at the top, pressing the first (left) button, and with the button held down, move the mouse until the window is in the desired location. Then release the button. (Moving the mouse with the button held down is called dragging.) You can resize the window by moving the mouse to the lower right corner. When the white circle appears, depress the first mouse button and drag the corner until the window has the desired size. If you want to view something in the window that has already scrolled past the top, you can drag the scroll bar at the left side of the window with the second (middle) mouse button to bring it back into view.

If you want to close the window, put the mouse on the title bar and depress the third (right) button. A pop-up menu will appear. To make a selection from this menu, drag the mouse until your selection is highlighted, then release the button. If you select "Close," your window will be saved, and an icon will appear at the bottom of the Workspace. You can reopen the window by placing the mouse on the icon and double-clicking with the first button. If you select "Quit," the application will be terminated, and the contents of the window will be lost. (There are other menus, with additional options, that come up if you hold down the Control key and click a mouse button.)

This isn't an issue when there is just one window in the Workspace, but sometimes you will have several windows open that overlap one another, and you will need to know how to bring the window that you want to work on to the top of the stack. You do this by placing the mouse on the title bar and clicking once with the first button. If you double click, the window goes to the bottom of the stack.

With overlapping windows it is possible to have many windows open at once. But this is not a good practice unless you are really using these windows. Open windows, even if inactive, consume memory, both in your terminal and in its host (theory). This has an adverse effect on the performance of the system, both for you and for other users. In fact, having too many open applications may cause your terminal to crash, so that you lose any unsaved work. In view of this danger, always remember to save your work frequently.

For many applications, it is possible to select text in one window and paste it into another window. You can select a single word by double clicking on it with the first button. To make a longer selection, click with the first button at the beginning of your selection and with the third button at the end; the selection will then become highlighted. You can extend the selection by clicking the third button again. To paste, place the cursor where you want your selection to go, and click the second button. Clear you selection by clicking anywhere with the first button. If you need to have more than one selection in the buffer at once, there is an application that allows you to do this; choose "Clipboard" from the Applications menu.

If your terminal hangs or crashes, you should know how to reboot it. On NCD terminals, press the Pause/Break key or the Setup key to bring up a menu where you can select Reboot under the Console menu. If neither of these succeeds in bring your terminal back, you can try turning the power on the machine off and then on (wait about 15 seconds before turning it back on). If this still doesn't solve the problem, there's probably a problem with the server - talk to the SysAdmin.

 

Using a Linux Box

If you have a PC on your desk, then you should be running RedHat Linux, a UNIX type operating system. When you first log in you should notice a bar at the bottom of the screen. On the leftmost side there is a footprint, which is the main menu (the equivalent of the start button in Windows). Next to it you should find other icons that when clicked will start different programs. The icon that looks like a television will start a standard terminal (which could be used for example to connect to theory). The icon with the big N launches Netscape, and the icon with the toolbox will allow you to configure your computer.

You should note that all your files will be stores on the hard drive of your Linux box. You have another set of files (plus mail) which is located on theory. To access your Linux files on theory, you will first have to copy them over using scp (see the remote access webpage for more details).

To access your theory files, or theory mail on the Linux box you will have to first ssh to theory. Just start a terminal by clicking on the television icon, then type "ssh theory" and hit return. All the commands you run in that window (like pine, to read mail) will then run on theory.

If the computer gets stuck, you should try rebooting it by pressing CTRL, ALT and F1 all at the same time, followed by CTRL, ALT and DELETE all at the same time. If the problems persist, you should contact your system administrator.