6.001 Spring 98: Transferring files between the
6.001 lab and an Athena locker
The 6.001 Lab does not support the Kerberos authentication system. If
you telnet or FTP to an Athena workstation, you will be asked to type
your password, and this password will be transmitted over the network
in the clear (i.e., the information will not be encrypted). Anyone
snooping on the network will be able to see your password. Since this
is MIT, we assume that sniffers are on the network as a matter of
course. If you are going to type your password in the clear on the
network, you may as well publish it in the Tech.
So don't use FTP to Athena. Instead, there are two programs, called
load-work and save-work, that move your 6.001
working files back and forth between lab machines and your Athena
locker. These programs use scp (secure copy) to set up an
encrypted tunnel to Athena, and all communication goes through the
tunnel.
In general, when you work in the 6.001 Lab, your work is saved in a
directory called work. All your work for the semester will
end up in this directory, in files named, e.g.,
work/ps1-ans.scm, work/ps2-ans.scm, and so on. When
you log in with a floppy disk to a machine in the 6.001 lab, the
work directory is restored from the floppy. When you log
out, the directory is copied from the lab machine's hard disk back to
the floppy.
load-work and save-work work much the same way,
except they use a directory named u6001 in your Athena locker
rather than a floppy disk. You copy from Athena to the lab machine
when you start work in the lab, and copy the work directory
back to Athena when you are done. Once your files are on Athena, you
can copy them to and from a personal machine. (But again, if you type
your password over an unencrypted connection on the MIT network you
are asking for trouble. Use SCP or Kerberized FTP.)
To copy your work from a lab machine to
your Athena directory
- Open an xterm by pressing the left mouse button down on the grey
background and choosing "xterm" from the menu that appears.
- Now in the xterm type
save-work {your-athena-login-name}
E.g., if your login name is Alyssa, you would type
save-work alyssa
- The program will prompt for your Athena password and transfer the
files from the work directory to your Athena directory. They will be
placed in a subdirectory of your home directory called
u6001.
To copy your work from Athena to a lab machine
- Open an xterm by pressing the left mouse button down on the grey
background and choosing "xterm" from the menu that appears.
- Now in the xterm type
load-work {your-athena-login-name}
E.g., if your login name is Alyssa, you would type
load-work alyssa
- The program will prompt for your Athena password and transfer the
files from your Athena directory to the work directory. The file are
assumed to be on Athena in placed in a subdirectory of your home
directory called u6001.
Problems Using these Programs
We've found that there is a problem that can crop up using these tools
if certain dotfiles (such as .cshrc.mine or .environment) output text
during the login process. This confuses scp and the transfer
will not take place. In this case, you should edit your dotfiles so
that anything which prints output is placed either in .startup.tty
(for text-only logins) or .startup.X (for X logins). See the LA on
duty or send mail to 6001-head-la@ai.mit.edu if you need help fixing
your dotfiles.
Logging in to Athena from the 6.001 lab
It's common for students working in the 6.001 lab to simultaneously
log in to Athena so they can read email or waste time with Zephyr.
Don't do this using telnet.
Instead, use ssh (secure shell), which sets up an encrypted
tunnel, by typing
ssh {machine-name} -l
{your-athena-login-name}
E.g., if your login
name is Alyssa and you want to connect to an Athena dialup (all of
which support SSH), you would type
ssh athena.dialup -l
alyssa
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Last modified: February 4 1998, 10:19 PM