Getting Started

Introduction

The purpose of this lab is to familiarize you with our computer facilities. You will also learn how to use the web browser Netscape (if you don't already know) in order to access course materials.

The lab itself consists of a number of tasks which will help familiarize you with the computers we will be using in this course. All of the computers in the lab are Linux workstations with XWindows-based user interfaces.

Although we assume in the following that you have never logged into either type of computer, the machines have reasonably intuitive user interfaces. Therefore, rather than explaining how to do each task in gory detail, we will simply give you the tasks together with some optional explanations you can refer to if you find the tasks obscure or otherwise difficult. However, we encourage you to try to figure out how to do the tasks on your own. When that doesn't work, don't be shy: ask!

One important remark: In our introductory course, MC27, we encourage students to take advantage of the easy-to-learn user interfaces on the Linux workstations. Our tack in this course is quite different: your work will primarily be done through a Unix shell (also called a terminal), which is a program that allows you to issue system commands; and through emacs, which is a programming and editing environment especially well suited for our needs. In fact, we even encourage you to call up Netscape through the shell, although you are welcome to use any of the many GUI ways of calling it up, should you prefer.

Resources

The classrooms we will be using for the lab sessions (Olin 326 and 329) consists of about 28 Linux workstations which are part of the campus-wide computer network.

There is a printer in the small room adjoining the classroom/lab. Its name is mcs-lab, so if you need to select a printer to print to, that is the one you should use when in the third-floor Olin computer labs.

Each Gustavus student has been given a computer account; this handout assumes that you already have read your account letter and changed your password. If not, and you need help with this, let one of us know. It does not matter which workstation you log into; you will have access to all your files on all computers, since they are stored on a central file server.

The following instructions assume some familiarity with such terms as single-click, double-click, and drag, which refer to the use of the mouse (the small doohickey next to the keyboard). If you don't understand something or if the instructions seem impenetrable, don't worry. These are examples of things better shown than described in words. Ask your lab instructor or one of the tutors to explain it to you. Also, feel free to talk with your fellow students. Computers are unfortunately fraught with many arcane terms, and defining them all would unduly clutter these handouts. Fortunately, if you are not shy about asking someone when you have a question, you should get the hang of it fairly quickly.

Special instructions for check-off labs

A large number of the labs (including this one) are so-called check-off labs. By this we mean that you need to show that you have finished specific tasks, which will demonstrate to us a basic understanding of the material covered in the lab. When you have finished one of the designated tasks, you should show one of the lab instructors (David, Karl or Matt), each of whom has a class list, so that they can check you off on the given task.

Check-offs are worth one point each, and will be indicated in bold face in the labs.

Log in and use Netscape (1 point)

  1. Login to a Linux workstation and launch Netscape.
  2. We do not include instructions for these task because we figure that most of you already know how to do this. Furthermore, you can't even be reading this unless you are using a web browser such as Netscape, so these are basic boot-up tasks. We will briefly describe how to do this in the first class, and will help anyone who needs help during the first lab.

  3. Locate the Gustavus Adolphus College homepage by entering http://www.gustavus.edu/  in the Location box and pressing Enter. Since you may not want to remember this address for next time, select ``Add Bookmark'' under the Bookmarks menu. Next time you want to find the Gustavus homepage, select ``Gustavus Adolphus College'' under the Bookmark menu.

  4. Our personal homepages are located at

       http://www.gustavus.edu/~amos
       http://www.gustavus.edu/~wolfe
    
    The course home page is located at
      http://www.gustavus.edu/~mc38
    
    You may wish to bookmark these ask well.

  5. Check-off: Show one of the lab instructors that you have located the course homepage and added it to your bookmarks. (Feel free to leave netscape open, continue work, and get checked off for the this task and the next at the same time.)

The directory structure and Unix shell (1 point)

The Linux computers on campus share a tree-structured file system. This means that the files on the computers are located in directories, which may themselves include files and subdirectories, which may contain files and other subdirectories, ...

When your account was created, you were given a home directory in which you can store and create files and subdirectories. This home directory resides on a file server maintained by the Department of Information Technology (which is located on the first floor of Olin Hall). Since your home directory (as well as other user accounts) are automatically loaded onto the Linux, it really doesn't matter which specific computer you use. Whichever computer you use, you will have access to the files you created in your previous sessions.

For this course, we recommend you learn how to navigate the directory structure using a a shell or terminal window, which is less system dependent and graphically based than other methods. Click on the hyper-link below to go to the page that is appropriate for your system.

Following are some tasks which will help you learn how to view and manipulate the directory structure using a Unix shell on and SGI or Linux workstation.

  1. Open up a Shell or Terminal.
  2. A shell (also known as terminal) is a program that allows you to issue commands to the computer's operating system. Unfortunately, these commands are often somewhat arcane and difficult to remember. Fortunately, there aren't many commands that you need to remember.

    The easiest way to launch a shell is through the main menu for the Linux workstation. On a Linux workstation, get the main menu by holding down the left mouse button on the ``K'' in the lower left corner of the screen and select the ``Application'' menu and the ``Xterm'' submenu.

    The shell window will pop up, and you will be presented with a command line prompt from which you can issue commands. How it looks will vary from person to person, but will probably end with the % character.

  3. Find out your present work directory.
  4. As described before, each computer user at Gustavus has a home directory that is stored on the central file server. When you start up a shell, the present work directory is your home directory. To see what that is, type pwd. (You must press the ``Enter'' key to actually issue the command.) Do so. Your home directory should end with your username.

  5. View your home directory.
  6. You can view the present work directory by entering the command ls. This will list all files and directories in the present work directory.

    To get a more informative listing, type ls -l. This gives more information about the files and directories.

  7. Add some sub-directories (also known as folders) to your home directory.
  8. To add a directory called mc38 into your home directory, type mkdir mc38. Do so, and then type ls -l to see the newly created sub-directory.

  9. Check-off: Move to the mc38 subdirectory and do a pwd to show that you are there and a directory listing to show that it is currently empty.
  10. You can move to mc38 by typing cd mc38 (think of cd as Change Directory). Do so.

    Typing cd .. will cause you to move up one directory in the file system; typing cd will take you to your home directory.

Logout

After finishing work on your computer, be sure to always logout so that a future student won't (inadvertently, I would hope) change your files. On the Linux workstations, push the left mouse over the ``K'' again, and select the ``Logout'' menu item.

Follow-up

The Linux workstations are general purpose computers that have a wide range of applications, including word processors, electronic mail, mathematical applications (Maple), and programming tools, to name just a few. As long as you remain a responsible user, you are welcome to use these applications as you please for other academic purposes. However, if you are working on something other than a math or computer science project, and all the machines fill up, please give your machine up for a student working on math or computer science. That way, with a little common courtesy, we can get the maximum benefit out of these facilities and still respect the fact that they've been funded for use in mathematics and computer science.

One problem you will encounter is how to make yourself aware of all of the applications available to you. This is a rather daunting task, and one which we will not directly address in this course. Instead, we suggest that you make use of the main source of useful computer arcana and trivia we have found, namely your fellow computer users. We are always learning new things from our students. So don't be shy!