Sorry, my mail got posted before completion.
1- So, as I said, rsh is for executing
a command on a remote computer. If you are on the machine X and have an account on computer Y where you want to execute the program Mathematica,
issue on your computer X :
The remote machine has to have its rshd (rsh daemon ) running.
Look at the web page on my preceding post for details.
2- ssh is to connect to a remote machine. It is a replacement for telnet. The problem with telnet is that the password you type can be read by any sniffer on the network. ssh use a public key algorithm to crypt the passwd, so what the sniffer reads is of no use to him.
> ssh myname@Y.mydo
> passwd ?
when your connection is accpted on the remote computer, you get whatever shell is your default on this computer.
The remote machine has to have its sshd running.