Computer Science
Computing handbook

Student Computing Handbook

Introduction

In the computer science department there are two types of machines available in the student labs: Macs and Linux PCs. Room 1063 contains Macs, while rooms 1060 and 1059 contain Linux PCs. You may use either lab for your assignment work. Most first year pracs will be conducted on the Macs in room 1063. Details on all of the labs is available at http://www.cs.adelaide.edu.au/for/students/labs/

For most purposes, either type of machine should be fine to use for your work. For many tasks, you will use the UNIX shell (covered shortly) which is basically the same on both platforms. You may encounter a few differences in configuration and software availability between the two types of machines.

Logging in

When you first sit down at a machine, you will be prompted for your user name and password. Your user name is the letter 'a' followed by your student number, e.g. a1234567. You should have received an information sheet giving your your password; if not, please contact your prac demonstrator for assistance. This password is the same one you will use for all other university systems, including email. You should ensure that you keep this password to yourself and do not share it with others.

Once logged in, you will be presented with a graphical desktop environment. This will be different depending on whether you are using a Mac or Linux machine. If you are not already familiar with the desktop environment you should spend some time exploring the menus, available applications etc. so that you know your way around.

Navigating around the system

Mac OS X

On a Mac, you use an application called the Finder. This lets you browse through directories on the hard disk and in your home directory on the network file server. You can browse the file system by double clicking on Macintosh HD on the desktop, and then double clicking on different folders to view their contents.

On the left hand side of the Finder window you will see a home icon with your user name; clicking on this will take you to your home directory. Any files you save here will be accessible from other computers in the labs.

At the bottom of the screen you will see the dock. This contains icons for some of the applications installed on the computer, including any applications you are currently running. You can launch these just by clicking on the icons, e.g. the compass icon which will launch Safari, with which you can browse the web. You can access other applications by going to the Applications folder in the Finder (under Macintosh HD). If you use an application regularly, you can drag its icon from this folder to the dock, so that it can be launched with a single click.

Linux

Under Linux you can browse around the file system using the Nautilus file manager. Just double click on the home icon on the desktop, and you will see the contents of your home directory on the network. You can also look through the contents of the local file system on the computer's hard disk via the computer icon. When using the file manager, you may find it useful to switch to list mode (click on View -> View as List).

To see what applications are installed on the machine, click on the Applications menu at the top of the screen. You can easily launch programs like Firefox (for web browsing) or the terminal from here.

The UNIX shell

Both Linux and Mac OS X are based on UNIX, the platform of choice for many computer scientists and software developers. UNIX features a command-line interface with which you can perform tasks by typing in text-based commands and viewing responses printed out on the terminal by the computer. If you have previously only used Windows (or the graphical desktop on the Mac), this can take a bit of getting used to, but with a bit of practice you'll find it just as easy to use (if not more) than graphical tools. There are a number of important advantages to using the command line interface, which you'll learn more about as you go through your courses.

To bring up a terminal, do the following:

• Linux: Go to the menu and select Applications -> Accessories -> Terminal
• Mac OS X: Click on "Macintosh HD" and navigate to Applications -> Utilities, then double click on Terminal. You can also drag the Terminal icon to the dock (at the bottom of the screen) so you can launch it more easily in the future.

Go through lessons 1-4 of the tutorial at http://www.ee.surrey.ac.uk/Teaching/Unix/ to learn the basics. You may wish to look at the other lessons at some later point in time, but the first 4 will be enough to get you started. Note that in lesson 2 there is a reference to a file science.txt which does not exist on our system; you can use /etc/services instead when going through this lesson on the CS machines.

Editing text files

During your course work you will need to use a text editor to work with various types of files, such as program source code. While you can use any text editor you like, we recommend Emacs. You can access this as follows:

• Linux: Go to the menu and select Applications -> Programming -> Emacs Text Editor
• Mac OS X: Navigate to the Applications directory in the Finder and double click on Aquamacs Emacs. As with Terminal, it's a good idea to drag this to your dock so you can access it more easily.

Some of the keyboard shortcuts for emacs are as follows:

• Ctrl-x-f: Open file. Type the filename at the prompt at the bottom of the window. You can also use this to create new files.
• Ctrl-x-s: Save file
• Ctrl-h then t: Bring up tutorial. This will explain the basics of how to edit files in Emacs.
• Ctrl-a: Move to start of line
• Ctrl-e: Move to end of line
• Ctrl-x then u: Undo

Copying and pasting work as follows:

• Select text with the mouse, or by pressing Ctrl-space and then moving the cursor to set the region you want to copy
  (Note: Ctrl-space may not work properly on the Linux machines, in which case you can use Ctrl-Shift-@ instead)
• To copy text to the clipboard, press Alt-w
• To cut text (copy + remove), press Ctrl-w
• To paste text, move the cursor to the appropriate place, and press Ctrl-y

The Mac version of Emacs will, by default, open each file in a separate window. You may wish to disable this behaviour using the menu item "Options->Display Buffers in Separate Frames". This can be useful when editing many different files, e.g. source files of a program.

Accessing the Internet

Firefox is installed on the Linux machines, and Safari on the Macs. When you first try to access the Internet, you will be prompted for your user name and password to access the proxy server. These are the same as what you used to log in to the machines. On the Macs, you can select "Remember this password in my keychain" to avoid having to type it in every time.

Your student account has a limited quota for Internet access. In 2009, this is 1Gb per semester for undergraduate students. This quota only applies to external websites, not for websites hosted internally by the university. If you exceed your quota, you may purchase additional access from the student centre. More information on this is available at http://www.adelaide.edu.au/student/current/snap/howdoesitwork.html

Please be aware that your use of the Internet is subject to the University's acceptable use policies and guidelines. You can find more information on these at http://www.adelaide.edu.au/its/it_policies/ and http://www.adelaide.edu.au/policies/?565.

University email

The university provides a web-based email service which you can access at http://webmail.adelaide.edu.au/. Further information on this is available at http://webmail.adelaide.edu.au/userguide/

Your email user name and password is the same as what you use when logging in to the CS machines.

Changing your password

If you need to change your password, see the instructions here:

https://password.adelaide.edu.au/IDM/jsps/login/Login.jsf

Any changes you make to your password will apply to all university systems, including email and the CS machines.

Printing

Several printers are available for use in the student labs. The lab machines are configured to use these, and you can select the appropriate printer from the print dialog in most applications. The names of the printers are the same as the room numbers; you can select an appropriate one when you print a document from any application.

You are initially given a print quota of $30 per semester, which equates to around 300 pages. This quota applies to printers in all student computer labs throughout the university. If it runs out, you can purchase additional quota at the student centre. For more information, and to check your current quota, see http://www.adelaide.edu.au/student/current/printing/

Subversion

The computer science department uses a system called Subversion for managing and storing files. This enables you to keep a backup of your work, as well as store different versions that can later be retrieved and compared. You will use Subversion during some of your courses for storing files that you create.

A set of instructions on how to use Subversion is available at http://www.cs.adelaide.edu.au/docs/svn-instr.pdf

Forums

Where to get help

If you run into problems with the lab computers or need help using the installed software, contact your prac demonstrator for assistance. In many cases you can also go to the help menu within applications, or use the man command to learn how to use command-line applications in the UNIX shell.