On Telnet and FTP

Telnet and FTP are network services (broadly similar to HTTP -- the Web -- or news, or email, etc.).  They allow you limited access to other machines on the Internet; depending on how these other machines are set up, you can perform a wide variety of actions using these services.  The Atrium lab is set up fairly restrictively; essentially you are allowed to use these services only to access your account -- and you must provide your username and password in order to do so.  Below I'll describe briefly what you might wish to use these services for and how to go about using them (I'll focus only on what you are most likely to want to do in the Atrium environment; there's quite a bit more to these services if you wish to explore them).  I'll also assume you're working from a PC; the same services are available on a Mac but with perhaps a little more effort.

Telnet

Use telnet to be able to execute UNIX commands (such as gcc, vi, pico, pine, etc....) from your home computer (or any other Internet-connected machine).  You can use the UNIX program development environment from your favorite physical surroundings.

Telnet allows you to set up a 'terminal' connection with another machine; that is, once you have create the connection, using it is like typing on the machine's own keyboard (except that you can't use any of the machine's graphics features).

There are two ways you can use telnet to access Atrium machines.

The easy way:  Here is a list of links that will open telnet connections to machines in the Atrium lab.  Clicking on one of these links will open a new window, and you will (perhaps after a brief wait) be asked for your username and password, exactly as if you were in the Atrium lab:

Once you login, you can use UNIX commands just as if you were actually at the machine.

The harder way:  from an MS-DOS window, or from the Run... option accessible from the Start button, type telnet.  This will open a similar window, but without making a connection to another machine.  From the Connect menu, pick the Remote System... option, which will bring up a dialog box like so:

You need only fill in the Host Name box with the name of a machine, then click the Connect button.  You can find out what names are available from the link above -- rather than clicking on a link, just move your mouse over the link to view the URL at the bottom of your browser window; they're of the form telnet://atrium65.its.brooklyn.cuny.edu.  The portion after the double-slash is the machine name; you may use any of these for your telnet connection (or your ftp connection, next).

To finish your telnet session, just logout as you would from the actual Atrium computer itself, and the telnet connection will automatically be closed.

FTP

Use FTP to move files back and forth from your home computer to your Atrium account.  You might want to upload source files that you've developed using Turbo on your PC, then, once you've transferred the source file, use telnet to execute the compilation commands (and actually execute the program itself).  You may also want to download source files from your Atrium account so you can print them on your printer at home.

FTP stands for File Transfer Protocol; it's a service that allows you to, er, transfer files from one machine to another (using the Internet).  Using ftp is very similar to using telnet, except that no-one has created a handy web page with automatic ftp links on it.  Instead, there's only the 'hard' way.  Again, from your MS-DOS window or from the Run... window, type ftp.  This will bring up a new prompt, probably something like

ftp>
Now you can begin giving ftp commands.  The first you'll probably want to give is open (or o for short):
ftp>  o atrium90.its.brooklyn.cuny.edu
Once you do this, a connection will be made to that machine, and you will be asked for your username and password.  After your successful authentication you may begin to transfer files.  At this point, your "working directory" on the Atrium machine is your home directory, so you may need to change to a subdirectory:  the UNIX cd command works for FTP, as does the ls command to show you the files in the working directory.  To move a file from the UNIX machine to your machine, use the get command, as
ftp>  get homework1.c
This will copy the file to your PC, most likely in the C: folder.  If you want the file to be put somewhere else, specify it like this:
ftp>  get homework1.c C:\Turbo\homework1.c
To transfer files from your PC to the Atrium machine, use the put command; you'll need to specify exactly what folder the file you're put-ting is in, as
ftp>  put C:\Turbo\CIS15\Homework1\homework1.c
This will put a file called homework1.c in the working directory on the UNIX machine.

If you forget a command, or want to learn about more commands, you can just type ? to get a list of commands, or (for example) ? ls to get a brief description of a command.  To exit ftp type bye.

One note of caution:  since you're probably only going to be transferring text files, you probably won't need to do anything special, but if you do decide (for whatever reason) to transfer a 'binary' file (an executable, an image file -- anything that's not human-readable), you must type the command binary before doing a get or a put -- this puts ftp into the 'binary transfer mode' which is necessary for working with binary files.