You can write your programs on your own machine (or any other machine), or if you want, you can use the UMD Glue/Grace machines.
To log into the Glue/Grace machines you should use an SSH client. (SSH client is a program that runs on your system. For most *NIX machines or a Mac just type ssh in the terminal. In windows you can use PuTTY). You should be able to log in to Glue/Grace using your university directory ID and password. Glue/Grace has both Solaris and Linux servers accessible but we strongly recommend that you only use Linux machines so for example you should type ssh yourname@linux.grace.umd.edu.
Some additional disk space has been reserved for you on Glue/Grace. The main class directory is /afs/glue.umd.edu/class/fall2010/cmsc/423/0101 . Within the student sub-directory, each of you should already have a directory set up. You can use this directory to store your work.
If you want, you can write your programs on your own computer and then upload them to the Glue/Grace servers (using scp or other SSH file transfer tool like WinSCP for Windows) or just simply edit and compile the programs directly on the servers. You need to make sure that your code compiles and runs on the servers, since this is where it will be tested.
You can write the programs with the editor of your choice but I recommend a simple *NIX editor like emacs, vim, nano etc.
GNU C and C++ (gcc and g++) compilers are installed on all these machines. Java is also available (see below for setting it up).
Some popular software is already available on these servers. type tap to see a list of available applications. For example you can type tap java6 to use Sun java compiler and runtime environment (javac and java) and tap R to use R statistical programming environment.